From patchwork Fri Apr 22 21:05:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824148 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C91F5C433F5 for ; Fri, 22 Apr 2022 22:12:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232130AbiDVWPo (ORCPT ); Fri, 22 Apr 2022 18:15:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231949AbiDVWP1 (ORCPT ); Fri, 22 Apr 2022 18:15:27 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A09E190088 for ; Fri, 22 Apr 2022 14:05:51 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id l16-20020a25cc10000000b006456cb3d1deso6823091ybf.14 for ; Fri, 22 Apr 2022 14:05:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ktDpzPoEdSrcrUnITrmIICEFHz35bcwHx2m+itC59DQ=; b=NuUyT27h7C++sSsmxph7YDVnlVq9JEo2qNd/NHlqu/pFwe1ZaK/DqFkIUFejxWDZ+L HCFTyNkmdUQQpAdlAE2EkZPO7+NrKCh3q/AAd7bXPDPhOya7e3i6fTvDCMG8t6hQE5Nd LlAD1nOHAruz6us2mg92VCm+qVkIiLQazVDQ+39JAk9pvNX4s290hmOx785CWQUF5t8l A5vwsOA/rpOEPfHSx7Z1ShpIwVYbjqEzdgZPGBXOf3vJFRbopVHdJd29zqqqJTdtpec3 qba+yk3xoqB4ftlQhK5uXzW3eBe511TeE4WQjoUUhYWhQBZEwMZ0EgCcCM4XOXGcpVi/ 6mZw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ktDpzPoEdSrcrUnITrmIICEFHz35bcwHx2m+itC59DQ=; b=J5xyf7CLf2KnNlzD+peSoUBgDWJBCSv3t8F4hZhcmOSYGrTDNZXU6twLFs9qzdnOFn LJJgk98oHSyxUcOlQJPzZ3vHkZQQBPkDH88zUdfCJkDHEkAIcUPqfQ0CMYSpoYgVEYnN wTbrXcFGfMAUthDQcFKjFZP+Xsu/vflfto3c4SKjK/5Jh7OvbKAWoyo19OuE+Idm24N9 v5TKgcEhcu4xA4qlR33YjamYd6NjEIOuepx+cMRQBmHzLPjHqA6hhmUwudFwk/RxAMvT ZbtQXlT2PNYlN+hNWArCyN/q2Icmd6oYh2zazDW2GGNWbAfsBY/1EX+VbVsp7XOUstug T60A== X-Gm-Message-State: AOAM531cLb5sc8/E7Sbosfn68BnN/TY4Ga1SSlYy7R45PJ7+33Vjq1GP ZML9FIUfKSmzUqKvGBJho+/dfyJkTZgrtA== X-Google-Smtp-Source: ABdhPJznlbTfpPgBcQWgSKtg2XkP7301qyrPyti3UXIeeQDW4BgY3Xl7oEU2Sfv4r0Q1kAkWzLGJ5G98i8gXew== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a25:bb4a:0:b0:633:92a6:c35 with SMTP id b10-20020a25bb4a000000b0063392a60c35mr6239899ybk.121.1650661550035; Fri, 22 Apr 2022 14:05:50 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:27 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-2-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 01/20] KVM: x86/mmu: Optimize MMU page cache lookup for all direct SPs From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Commit fb58a9c345f6 ("KVM: x86/mmu: Optimize MMU page cache lookup for fully direct MMUs") skipped the unsync checks and write flood clearing for full direct MMUs. We can extend this further to skip the checks for all direct shadow pages. Direct shadow pages in indirect MMUs (i.e. shadow paging) are used when shadowing a guest huge page with smaller pages. Such direct shadow pages, like their counterparts in fully direct MMUs, are never marked unsynced or have a non-zero write-flooding count. Checking sp->role.direct also generates better code than checking direct_map because, due to register pressure, direct_map has to get shoved onto the stack and then pulled back off. No functional change intended. Reviewed-by: Sean Christopherson Reviewed-by: Peter Xu Signed-off-by: David Matlack Reviewed-by: Lai Jiangshan --- arch/x86/kvm/mmu/mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) base-commit: 150866cd0ec871c765181d145aa0912628289c8a diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 69a30d6d1e2b..3de4cce317e4 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2028,7 +2028,6 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, int direct, unsigned int access) { - bool direct_mmu = vcpu->arch.mmu->root_role.direct; union kvm_mmu_page_role role; struct hlist_head *sp_list; unsigned quadrant; @@ -2070,7 +2069,8 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, continue; } - if (direct_mmu) + /* unsync and write-flooding only apply to indirect SPs. */ + if (sp->role.direct) goto trace_get_page; if (sp->unsync) { From patchwork Fri Apr 22 21:05:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824155 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3127BC433EF for ; Fri, 22 Apr 2022 22:13:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232096AbiDVWQJ (ORCPT ); Fri, 22 Apr 2022 18:16:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232027AbiDVWP1 (ORCPT ); Fri, 22 Apr 2022 18:15:27 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3E9403165C2 for ; Fri, 22 Apr 2022 14:05:52 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id f6-20020a170902ab8600b0015895212d23so5390019plr.6 for ; Fri, 22 Apr 2022 14:05:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=zNWYQ7iy7Yr89sIEde3cCb/Lt3WEldLKJ8vXDlDeSiQ=; b=Ppu58rFHVoI6iW5s1gyFZJw/q+6CTvIq3bwkrX6Bfha1v9ELmxlhB6kBdaxuhU8ALA oZJOS2zzPK79Cbz2PaFtDvWjGOXqa3Vag3MWGfOPw2XmGt9fNogG4PyBnIzfzwu0Cr2Z Z9Yd3xVeeD1MsLLmQbE33yT6gDJNnLmzjIhiqgCNEusUBTkk2ljA7jNZeivTms/fsolS 8ruvMsny7ijFMPJnejhTGx2b5qhO8OcB3N+OLEFjJPIKmS4RB11u8nQzg8mef19nDz4C hY7FnXWyO5/aoBz1LUQ06kXu09Mes4okVgaK01vet3BEhu0IBB9fZXiQPVzHWDrd/mUO dnWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=zNWYQ7iy7Yr89sIEde3cCb/Lt3WEldLKJ8vXDlDeSiQ=; b=uanpurC2naGxEx3nteTLzXbf3y20OpWKASq+koizF5yDRkOYXE2s1FtnbzaPhm20Ku Rf3m1ZF6aUF9NMcwR9p+XoIOsxHARCj9kg+YblJ8ampZEpcIP3A0PdXQapt6S29ptksQ hIepUeaDdF0igh0YIwr86kz5lI0HJTMsqTGyGEQHf+DytPhExpJrLqhD0zO51e/GXAhq 8RPV9CE3KOnuntpBvtK9llmNNt16JQVUO3S9DHfu9Vyg+fajepZBtunB92fMLV1JQ41Z wg9FGiok/8AqInWq8a6SDilhqI5E7PdciN8CYW9fCE6tJJVR85Y41z5u4Hhsva/uOowL StOA== X-Gm-Message-State: AOAM531L5qB2XNonXD0bEpDSO9BR9ohflgMnJoVgBNyKXte98jF7pYXc MaeZstsgEDXsb+xZFATz6shBN8ZMD6kL6w== X-Google-Smtp-Source: ABdhPJyWKXLx2/uwe0ElKVg7hOGiMwOVxhtzWi1NrbfYjD0XJGhsQ6VUWZmhsGO7iXcdNSRimP+xg/0T9I02hg== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:903:18f:b0:15a:d3e:1e47 with SMTP id z15-20020a170903018f00b0015a0d3e1e47mr6631600plg.54.1650661551615; Fri, 22 Apr 2022 14:05:51 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:28 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-3-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 02/20] KVM: x86/mmu: Use a bool for direct From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The parameter "direct" can either be true or false, and all of the callers pass in a bool variable or true/false literal, so just use the type bool. No functional change intended. Reviewed-by: Sean Christopherson Signed-off-by: David Matlack Reviewed-by: Lai Jiangshan --- arch/x86/kvm/mmu/mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 3de4cce317e4..dc20eccd6a77 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1703,7 +1703,7 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, int direct) +static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, bool direct) { struct kvm_mmu_page *sp; @@ -2025,7 +2025,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gaddr, unsigned level, - int direct, + bool direct, unsigned int access) { union kvm_mmu_page_role role; From patchwork Fri Apr 22 21:05:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824150 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44947C4332F for ; Fri, 22 Apr 2022 22:12:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231560AbiDVWPu (ORCPT ); Fri, 22 Apr 2022 18:15:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232274AbiDVWPb (ORCPT ); Fri, 22 Apr 2022 18:15:31 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 698BF3180C8 for ; Fri, 22 Apr 2022 14:05:54 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id w18-20020aa79552000000b0050ce4b883a1so3048004pfq.22 for ; Fri, 22 Apr 2022 14:05:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ydpkYBJyUQ0Pemf8xKE/Mq2pmxsnqz5SB827w848vds=; b=OdYoDK3Z7oncUrjt1o2sOXVEDhlYdm84kPLHDZ+vdWB42HFakWmY/wC05muXTVQD1g re1cYnVuTJJ1X1iqWM1Pig3Jl8DeWE1Hv7ROCjS53FY4jbSR0d4OTFdAnrzSKdBovcH6 h17J4qnOpXS6zsXDMzkuhnTVKYTsFAgVq2PTGyXZlZZZsuHU6X6VzOgXXoBh8mhQ1AkJ 92vts37W9f+wZxyZylfrqVg8ksGuVuvG8WtYzfkL7/tW2R1z4Jn5JLYxgSgOb12uLglb fqnjWn5i0PT75MFTaEvxcb/Oo9iBsq4KylETA06UsrvfPb/U8OZZir1svtW6S1tVylaD 6eSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ydpkYBJyUQ0Pemf8xKE/Mq2pmxsnqz5SB827w848vds=; b=A7zx0d15i+3YlS8ch5uf2gwBQlCF7hMShK2LtFcXC+gvQvfkGOrfcjW3ewuDX7B8ok BQSrFdzLq59OYflAFeFOqI+uPUKGBbEfZq/LUOHrsezAAHRD4KQ//58+7Jh888dPM0+W /SFhpwsiJuouan1jsD+oCWxR0n51mpiBcbhqSQxJrbNap2Cz07r3NPDSsDxthD2+zLqR z1LKyh9vF+7fuv7tDt71gfMtAUjG1SzQg5GtljDQf/vHJ2RNfpYarNHOu8buHHA62JtA 8oZNe1RSBnTVUomb+XZsXxvKDQndOLxb8TirqiL+nO3H8jz1ViDIZi41MeOPXGsZbyDD rnhQ== X-Gm-Message-State: AOAM530jnINaTr6V5aOo/lLCuBtNC23r2MwnxSaV+A0G41mQZ+ijwUQF qhpI7o8j9VOyqTiqDZadH/JuM7HmBHe7Fw== X-Google-Smtp-Source: ABdhPJwB54tgPDTSqKhBpGVcJcnTXrHs0usS6zL3MbUtwUQvqibR9Idj0lf9CfH/har6Ld5TSlyg9fqA83OgDA== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:90a:9105:b0:1d2:9e98:7e1e with SMTP id k5-20020a17090a910500b001d29e987e1emr620382pjo.0.1650661553286; Fri, 22 Apr 2022 14:05:53 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:29 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-4-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 03/20] KVM: x86/mmu: Derive shadow MMU page role from parent From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Instead of computing the shadow page role from scratch for every new page, derive most of the information from the parent shadow page. This avoids redundant calculations and reduces the number of parameters to kvm_mmu_get_page(). Preemptively split out the role calculation to a separate function for use in a following commit. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 96 +++++++++++++++++++++++----------- arch/x86/kvm/mmu/paging_tmpl.h | 9 ++-- 2 files changed, 71 insertions(+), 34 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index dc20eccd6a77..4249a771818b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2021,31 +2021,15 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sptep_to_sp(spte)); } -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, - gfn_t gfn, - gva_t gaddr, - unsigned level, - bool direct, - unsigned int access) +static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, + union kvm_mmu_page_role role) { - union kvm_mmu_page_role role; struct hlist_head *sp_list; - unsigned quadrant; struct kvm_mmu_page *sp; int ret; int collisions = 0; LIST_HEAD(invalid_list); - role = vcpu->arch.mmu->root_role; - role.level = level; - role.direct = direct; - role.access = access; - if (role.has_4_byte_gpte) { - quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level)); - quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1; - role.quadrant = quadrant; - } - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; for_each_valid_sp(vcpu->kvm, sp, sp_list) { if (sp->gfn != gfn) { @@ -2063,7 +2047,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, * Unsync pages must not be left as is, because the new * upper-level page will be write-protected. */ - if (level > PG_LEVEL_4K && sp->unsync) + if (role.level > PG_LEVEL_4K && sp->unsync) kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list); continue; @@ -2104,14 +2088,14 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, ++vcpu->kvm->stat.mmu_cache_miss; - sp = kvm_mmu_alloc_page(vcpu, direct); + sp = kvm_mmu_alloc_page(vcpu, role.direct); sp->gfn = gfn; sp->role = role; hlist_add_head(&sp->hash_link, sp_list); - if (!direct) { + if (!role.direct) { account_shadowed(vcpu->kvm, sp); - if (level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) + if (role.level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1); } trace_kvm_mmu_get_page(sp, true); @@ -2123,6 +2107,51 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, return sp; } +static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct, u32 access) +{ + struct kvm_mmu_page *parent_sp = sptep_to_sp(sptep); + union kvm_mmu_page_role role; + + role = parent_sp->role; + role.level--; + role.access = access; + role.direct = direct; + + /* + * If the guest has 4-byte PTEs then that means it's using 32-bit, + * 2-level, non-PAE paging. KVM shadows such guests using 4 PAE page + * directories, each mapping 1/4 of the guest's linear address space + * (1GiB). The shadow pages for those 4 page directories are + * pre-allocated and assigned a separate quadrant in their role. + * + * Since this role is for a child shadow page and there are only 2 + * levels, this must be a PG_LEVEL_4K shadow page. Here the quadrant + * will either be 0 or 1 because it maps 1/2 of the address space mapped + * by the guest's PG_LEVEL_4K page table (or 4MiB huge page) that it is + * shadowing. In this case, the quadrant can be derived by the index of + * the SPTE that points to the new child shadow page in the page + * directory (parent_sp). Specifically, every 2 SPTEs in parent_sp + * shadow one half of a guest's page table (or 4MiB huge page) so the + * quadrant is just the parity of the index of the SPTE. + */ + if (role.has_4_byte_gpte) { + WARN_ON_ONCE(role.level != PG_LEVEL_4K); + role.quadrant = (sptep - parent_sp->spt) % 2; + } + + return role; +} + +static struct kvm_mmu_page *kvm_mmu_get_child_sp(struct kvm_vcpu *vcpu, + u64 *sptep, gfn_t gfn, + bool direct, u32 access) +{ + union kvm_mmu_page_role role; + + role = kvm_mmu_child_role(sptep, direct, access); + return kvm_mmu_get_page(vcpu, gfn, role); +} + static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterator, struct kvm_vcpu *vcpu, hpa_t root, u64 addr) @@ -2927,8 +2956,7 @@ static int __direct_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) if (is_shadow_present_pte(*it.sptep)) continue; - sp = kvm_mmu_get_page(vcpu, base_gfn, it.addr, - it.level - 1, true, ACC_ALL); + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, true, ACC_ALL); link_shadow_page(vcpu, it.sptep, sp); if (fault->is_tdp && fault->huge_page_disallowed && @@ -3310,12 +3338,21 @@ static int mmu_check_root(struct kvm_vcpu *vcpu, gfn_t root_gfn) return ret; } -static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gva, +static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, int quadrant, u8 level, bool direct) { + union kvm_mmu_page_role role; struct kvm_mmu_page *sp; - sp = kvm_mmu_get_page(vcpu, gfn, gva, level, direct, ACC_ALL); + role = vcpu->arch.mmu->root_role; + role.level = level; + role.direct = direct; + role.access = ACC_ALL; + + if (role.has_4_byte_gpte) + role.quadrant = quadrant; + + sp = kvm_mmu_get_page(vcpu, gfn, role); ++sp->root_count; return __pa(sp->spt); @@ -3349,8 +3386,8 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) for (i = 0; i < 4; ++i) { WARN_ON_ONCE(IS_VALID_PAE_ROOT(mmu->pae_root[i])); - root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), - i << 30, PT32_ROOT_LEVEL, true); + root = mmu_alloc_root(vcpu, i << (30 - PAGE_SHIFT), i, + PT32_ROOT_LEVEL, true); mmu->pae_root[i] = root | PT_PRESENT_MASK | shadow_me_mask; } @@ -3519,8 +3556,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu) root_gfn = pdptrs[i] >> PAGE_SHIFT; } - root = mmu_alloc_root(vcpu, root_gfn, i << 30, - PT32_ROOT_LEVEL, false); + root = mmu_alloc_root(vcpu, root_gfn, i, PT32_ROOT_LEVEL, false); mmu->pae_root[i] = root | pm_mask; } diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index 66f1acf153c4..a8a755e1561d 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -648,8 +648,9 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, if (!is_shadow_present_pte(*it.sptep)) { table_gfn = gw->table_gfn[it.level - 2]; access = gw->pt_access[it.level - 2]; - sp = kvm_mmu_get_page(vcpu, table_gfn, fault->addr, - it.level-1, false, access); + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, table_gfn, + false, access); + /* * We must synchronize the pagetable before linking it * because the guest doesn't need to flush tlb when @@ -705,8 +706,8 @@ static int FNAME(fetch)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, drop_large_spte(vcpu, it.sptep); if (!is_shadow_present_pte(*it.sptep)) { - sp = kvm_mmu_get_page(vcpu, base_gfn, fault->addr, - it.level - 1, true, direct_access); + sp = kvm_mmu_get_child_sp(vcpu, it.sptep, base_gfn, + true, direct_access); link_shadow_page(vcpu, it.sptep, sp); if (fault->huge_page_disallowed && fault->req_level >= it.level) From patchwork Fri Apr 22 21:05:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824146 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B871DC433EF for ; Fri, 22 Apr 2022 22:12:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232469AbiDVWPi (ORCPT ); Fri, 22 Apr 2022 18:15:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232155AbiDVWPZ (ORCPT ); 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d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=qj35gLZCMYjMIw6N9BxxV9K4UpqK4GN2xsPfew8h1po=; b=X0DPK1l0TPUaV7pwvRvU/1jt6QRSYiJxAdHNJjoDPS5HdIcXig9ST9hF2ZmsP7YCb2 kG6xiHblWM6++wwVTmWiyLBVImp3oaezkYjerBIFC7Krw7GhcRmF/Or5sOR+8O0W0Pup mpHMFb2j0Zvqs1aSpOD5ViVQEGbQLpA1HRcSn+7H1wA5dTQqqfjQ5j/AyuRQbwmLyPy+ 6i4Hl6cD8PwosqLiz2gM9FitqXjUGUIh4CtSITpBA1hTHXAP47VEWF9NlFRIqDsdBUaf f/IY3OksxADc64GOAc4K/WkDawRqGRYa9IR8qFNB8S8j83nelq+DIiP+XCNdf0iSD4OG tx+Q== X-Gm-Message-State: AOAM531vskfU+UqXcF1UOFNfUqRp5NjjOF9HoO6+cwa4o8owVu2rDYYI S1oXi0fV7nrG/I/cmobYVqVpN0R7muKKgA== X-Google-Smtp-Source: ABdhPJz9+I2RcqkgbBc37x1EPNWRxfFKvB0IAHvRY78mXJGJY+nNWbIdU+DbOHi9vy5UgEQ9XRpwIo7McSbuHQ== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:902:aa4b:b0:15a:44e6:4efb with SMTP id c11-20020a170902aa4b00b0015a44e64efbmr6443542plr.64.1650661555076; Fri, 22 Apr 2022 14:05:55 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:30 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-5-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 04/20] KVM: x86/mmu: Decompose kvm_mmu_get_page() into separate functions From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Decompose kvm_mmu_get_page() into separate helper functions to increase readability and prepare for allocating shadow pages without a vcpu pointer. Specifically, pull the guts of kvm_mmu_get_page() into 2 helper functions: kvm_mmu_find_shadow_page() - Walks the page hash checking for any existing mmu pages that match the given gfn and role. kvm_mmu_alloc_shadow_page() Allocates and initializes an entirely new kvm_mmu_page. This currently requries a vcpu pointer for allocation and looking up the memslot but that will be removed in a future commit. No functional change intended. Signed-off-by: David Matlack Reviewed-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 52 +++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4249a771818b..5582badf4947 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2021,16 +2021,16 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sptep_to_sp(spte)); } -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, - union kvm_mmu_page_role role) +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + struct hlist_head *sp_list, + union kvm_mmu_page_role role) { - struct hlist_head *sp_list; struct kvm_mmu_page *sp; int ret; int collisions = 0; LIST_HEAD(invalid_list); - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; for_each_valid_sp(vcpu->kvm, sp, sp_list) { if (sp->gfn != gfn) { collisions++; @@ -2055,7 +2055,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, /* unsync and write-flooding only apply to indirect SPs. */ if (sp->role.direct) - goto trace_get_page; + goto out; if (sp->unsync) { /* @@ -2081,14 +2081,26 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, __clear_sp_write_flooding_count(sp); -trace_get_page: - trace_kvm_mmu_get_page(sp, false); goto out; } + sp = NULL; ++vcpu->kvm->stat.mmu_cache_miss; - sp = kvm_mmu_alloc_page(vcpu, role.direct); +out: + kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); + + if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) + vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; + return sp; +} + +static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + struct hlist_head *sp_list, + union kvm_mmu_page_role role) +{ + struct kvm_mmu_page *sp = kvm_mmu_alloc_page(vcpu, role.direct); sp->gfn = gfn; sp->role = role; @@ -2098,12 +2110,26 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, if (role.level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1); } - trace_kvm_mmu_get_page(sp, true); -out: - kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); - if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) - vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; + return sp; +} + +static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct hlist_head *sp_list; + struct kvm_mmu_page *sp; + bool created = false; + + sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; + + sp = kvm_mmu_find_shadow_page(vcpu, gfn, sp_list, role); + if (!sp) { + created = true; + sp = kvm_mmu_alloc_shadow_page(vcpu, gfn, sp_list, role); + } + + trace_kvm_mmu_get_page(sp, created); return sp; } From patchwork Fri Apr 22 21:05:31 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824154 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95C87C433EF for ; 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Fri, 22 Apr 2022 14:05:56 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:31 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-6-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 05/20] KVM: x86/mmu: Consolidate shadow page allocation and initialization From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Consolidate kvm_mmu_alloc_page() and kvm_mmu_alloc_shadow_page() under the latter so that all shadow page allocation and initialization happens in one place. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 5582badf4947..7d03320f6e08 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1703,27 +1703,6 @@ static void drop_parent_pte(struct kvm_mmu_page *sp, mmu_spte_clear_no_track(parent_pte); } -static struct kvm_mmu_page *kvm_mmu_alloc_page(struct kvm_vcpu *vcpu, bool direct) -{ - struct kvm_mmu_page *sp; - - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); - if (!direct) - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); - set_page_private(virt_to_page(sp->spt), (unsigned long)sp); - - /* - * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() - * depends on valid pages being added to the head of the list. See - * comments in kvm_zap_obsolete_pages(). - */ - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); - kvm_mod_used_mmu_pages(vcpu->kvm, +1); - return sp; -} - static void mark_unsync(u64 *spte); static void kvm_mmu_mark_parents_unsync(struct kvm_mmu_page *sp) { @@ -2100,7 +2079,23 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, struct hlist_head *sp_list, union kvm_mmu_page_role role) { - struct kvm_mmu_page *sp = kvm_mmu_alloc_page(vcpu, role.direct); + struct kvm_mmu_page *sp; + + sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); + sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); + if (!role.direct) + sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); + + set_page_private(virt_to_page(sp->spt), (unsigned long)sp); + + /* + * active_mmu_pages must be a FIFO list, as kvm_zap_obsolete_pages() + * depends on valid pages being added to the head of the list. See + * comments in kvm_zap_obsolete_pages(). + */ + sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; + list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); + kvm_mod_used_mmu_pages(vcpu->kvm, +1); sp->gfn = gfn; sp->role = role; From patchwork Fri Apr 22 21:05:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824151 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFA41C433FE for ; Fri, 22 Apr 2022 22:13:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232206AbiDVWPx (ORCPT ); Fri, 22 Apr 2022 18:15:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232329AbiDVWPe (ORCPT ); Fri, 22 Apr 2022 18:15:34 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0CCB31830B for ; Fri, 22 Apr 2022 14:05:58 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id d6-20020aa78686000000b0050adc2b200cso4222786pfo.21 for ; Fri, 22 Apr 2022 14:05:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=G+IdVJXdYDhurbFroRPmjGDa1DIMEsmyq4Ddc1Azx9o=; b=EeyUWY2A4YUtjFoIIod7jT45VsiREZstTaA42bdkZqFNKhVo2SMK/fMIxUhW4DH1tp M2aI2Xj1/z4SM30Fmts5NZSRb/yoSP93dC/g5wuByUiwqviCCQZMHJd8+awIag9yc0aG N/ppv0ovSpjzHUSA4IrZNIOQK1lRLQIAbn4qQVfPHn+gEeo7QsmjPUzlemhWbjQtgcBz FSAj1Hs6lPvHcFyL8Ojoy+4pfj0q+QMsO3hDv221SOACAhNlSJ4zDYZxCZIPdsIjhE7L j7xzpZWeRlNkkq3GimoL+K1SHkhvKTMVcYFOO4Mnu7lrezdT7tjUjU6LkPdPgUwbjy0Q M9NQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=G+IdVJXdYDhurbFroRPmjGDa1DIMEsmyq4Ddc1Azx9o=; b=Slk/DTbbL4Dr8xr93HxJ///BlGg0lHZLmwTcsu95T1xGNTZnr4S5GvujWJkHcwjnp9 BeayjYC7b1qlbUlf8qTTitfTmgHsXUsbe9AvkFe/D+mU8lD1e3PcRP5rc70vXsfpXLz8 CoDLRzFxNR3+acHJDMdV7BJsaJ5Or2EARyQuoLFmMvIV8B/O91hQEl1rNvL0EJd41cFN 2+s6UTz7TrmBG4fsxhQuiR79a7hiNwA0w3lss36qAd00obOXsNA4nAsCwK1sTeDCjf2/ Z+Vxdvvm5VKE1U1Y+qBY3HmFrISM9F751R2aCYw21EziAD8aZxVHZo5Vev8Th7ILCWll 4b9g== X-Gm-Message-State: AOAM530ph2xSQBYjodSQyWN3RGiTbXhPW+xhTxP7zjDcoo0yZzYg2bLZ hBh1PkMBZeBYtraLpnixcyjSYdOUmc+L0A== X-Google-Smtp-Source: ABdhPJwwvXSyIvHO4DIC1Zg0E+/dsC/+AVEA3dqe0F5WNIeQzUllDkrwU+ob9coEjnUqWO2CMgBhrQNjgYpxUQ== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a62:170b:0:b0:50a:6901:b633 with SMTP id 11-20020a62170b000000b0050a6901b633mr6951474pfx.34.1650661558373; Fri, 22 Apr 2022 14:05:58 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:32 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-7-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 06/20] KVM: x86/mmu: Rename shadow MMU functions that deal with shadow pages From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Rename 2 functions: kvm_mmu_get_page() -> kvm_mmu_get_shadow_page() kvm_mmu_free_page() -> kvm_mmu_free_shadow_page() This change makes it clear that these functions deal with shadow pages rather than struct pages. It also aligns these functions with the naming scheme for kvm_mmu_find_shadow_page() and kvm_mmu_alloc_shadow_page(). Prefer "shadow_page" over the shorter "sp" since these are core functions and the line lengths aren't terrible. No functional change intended. Signed-off-by: David Matlack Reviewed-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 7d03320f6e08..fa7846760887 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1665,7 +1665,7 @@ static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, long nr) percpu_counter_add(&kvm_total_used_mmu_pages, nr); } -static void kvm_mmu_free_page(struct kvm_mmu_page *sp) +static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp) { MMU_WARN_ON(!is_empty_shadow_page(sp->spt)); hlist_del(&sp->hash_link); @@ -2109,8 +2109,9 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, return sp; } -static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, - union kvm_mmu_page_role role) +static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + union kvm_mmu_page_role role) { struct hlist_head *sp_list; struct kvm_mmu_page *sp; @@ -2170,7 +2171,7 @@ static struct kvm_mmu_page *kvm_mmu_get_child_sp(struct kvm_vcpu *vcpu, union kvm_mmu_page_role role; role = kvm_mmu_child_role(sptep, direct, access); - return kvm_mmu_get_page(vcpu, gfn, role); + return kvm_mmu_get_shadow_page(vcpu, gfn, role); } static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterator, @@ -2446,7 +2447,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, list_for_each_entry_safe(sp, nsp, invalid_list, link) { WARN_ON(!sp->role.invalid || sp->root_count); - kvm_mmu_free_page(sp); + kvm_mmu_free_shadow_page(sp); } } @@ -3373,7 +3374,7 @@ static hpa_t mmu_alloc_root(struct kvm_vcpu *vcpu, gfn_t gfn, int quadrant, if (role.has_4_byte_gpte) role.quadrant = quadrant; - sp = kvm_mmu_get_page(vcpu, gfn, role); + sp = kvm_mmu_get_shadow_page(vcpu, gfn, role); ++sp->root_count; return __pa(sp->spt); From patchwork Fri Apr 22 21:05:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824152 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D25DCC43217 for ; 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Fri, 22 Apr 2022 14:05:59 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:33 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-8-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 07/20] KVM: x86/mmu: Move guest PT write-protection to account_shadowed() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Move the code that write-protects newly-shadowed guest page tables into account_shadowed(). This avoids a extra gfn-to-memslot lookup and is a more logical place for this code to live. But most importantly, this reduces kvm_mmu_alloc_shadow_page()'s reliance on having a struct kvm_vcpu pointer, which will be necessary when creating new shadow pages during VM ioctls for eager page splitting. Note, it is safe to drop the role.level == PG_LEVEL_4K check since account_shadowed() returns early if role.level > PG_LEVEL_4K. No functional change intended. Signed-off-by: David Matlack Reviewed-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index fa7846760887..4f894db88bbf 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -807,6 +807,9 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp) KVM_PAGE_TRACK_WRITE); kvm_mmu_gfn_disallow_lpage(slot, gfn); + + if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K)) + kvm_flush_remote_tlbs_with_address(kvm, gfn, 1); } void account_huge_nx_page(struct kvm *kvm, struct kvm_mmu_page *sp) @@ -2100,11 +2103,9 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, sp->gfn = gfn; sp->role = role; hlist_add_head(&sp->hash_link, sp_list); - if (!role.direct) { + + if (!role.direct) account_shadowed(vcpu->kvm, sp); - if (role.level == PG_LEVEL_4K && kvm_vcpu_write_protect_gfn(vcpu, gfn)) - kvm_flush_remote_tlbs_with_address(vcpu->kvm, gfn, 1); - } return sp; } From patchwork Fri Apr 22 21:05:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824153 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C738BC433F5 for ; Fri, 22 Apr 2022 22:13:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232508AbiDVWP6 (ORCPT ); Fri, 22 Apr 2022 18:15:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232348AbiDVWPe (ORCPT ); Fri, 22 Apr 2022 18:15:34 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4F4D318316 for ; 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Fri, 22 Apr 2022 14:06:01 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:34 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-9-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 08/20] KVM: x86/mmu: Pass memory caches to allocate SPs separately From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Refactor kvm_mmu_alloc_shadow_page() to receive the caches from which it will allocate the various pieces of memory for shadow pages as a parameter, rather than deriving them from the vcpu pointer. This will be useful in a future commit where shadow pages are allocated during VM ioctls for eager page splitting, and thus will use a different set of caches. Preemptively pull the caches out all the way to kvm_mmu_get_shadow_page() since eager page splitting will not be calling kvm_mmu_alloc_shadow_page() directly. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4f894db88bbf..943595ed0ba1 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2077,17 +2077,25 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, return sp; } +/* Caches used when allocating a new shadow page. */ +struct shadow_page_caches { + struct kvm_mmu_memory_cache *page_header_cache; + struct kvm_mmu_memory_cache *shadow_page_cache; + struct kvm_mmu_memory_cache *gfn_array_cache; +}; + static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, + struct shadow_page_caches *caches, gfn_t gfn, struct hlist_head *sp_list, union kvm_mmu_page_role role) { struct kvm_mmu_page *sp; - sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); - sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); + sp = kvm_mmu_memory_cache_alloc(caches->page_header_cache); + sp->spt = kvm_mmu_memory_cache_alloc(caches->shadow_page_cache); if (!role.direct) - sp->gfns = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_gfn_array_cache); + sp->gfns = kvm_mmu_memory_cache_alloc(caches->gfn_array_cache); set_page_private(virt_to_page(sp->spt), (unsigned long)sp); @@ -2110,9 +2118,10 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, return sp; } -static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, - gfn_t gfn, - union kvm_mmu_page_role role) +static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, + struct shadow_page_caches *caches, + gfn_t gfn, + union kvm_mmu_page_role role) { struct hlist_head *sp_list; struct kvm_mmu_page *sp; @@ -2123,13 +2132,26 @@ static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, sp = kvm_mmu_find_shadow_page(vcpu, gfn, sp_list, role); if (!sp) { created = true; - sp = kvm_mmu_alloc_shadow_page(vcpu, gfn, sp_list, role); + sp = kvm_mmu_alloc_shadow_page(vcpu, caches, gfn, sp_list, role); } trace_kvm_mmu_get_page(sp, created); return sp; } +static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, + gfn_t gfn, + union kvm_mmu_page_role role) +{ + struct shadow_page_caches caches = { + .page_header_cache = &vcpu->arch.mmu_page_header_cache, + .shadow_page_cache = &vcpu->arch.mmu_shadow_page_cache, + .gfn_array_cache = &vcpu->arch.mmu_gfn_array_cache, + }; + + return __kvm_mmu_get_shadow_page(vcpu, &caches, gfn, role); +} + static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct, u32 access) { struct kvm_mmu_page *parent_sp = sptep_to_sp(sptep); From patchwork Fri Apr 22 21:05:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824166 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3EC4BC433F5 for ; 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Fri, 22 Apr 2022 14:06:02 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:35 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-10-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 09/20] KVM: x86/mmu: Replace vcpu with kvm in kvm_mmu_alloc_shadow_page() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The vcpu pointer in kvm_mmu_alloc_shadow_page() is only used to get the kvm pointer. So drop the vcpu pointer and just pass in the kvm pointer. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 943595ed0ba1..df110e0d57cf 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2084,7 +2084,7 @@ struct shadow_page_caches { struct kvm_mmu_memory_cache *gfn_array_cache; }; -static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, +static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, struct shadow_page_caches *caches, gfn_t gfn, struct hlist_head *sp_list, @@ -2104,16 +2104,16 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm_vcpu *vcpu, * depends on valid pages being added to the head of the list. See * comments in kvm_zap_obsolete_pages(). */ - sp->mmu_valid_gen = vcpu->kvm->arch.mmu_valid_gen; - list_add(&sp->link, &vcpu->kvm->arch.active_mmu_pages); - kvm_mod_used_mmu_pages(vcpu->kvm, +1); + sp->mmu_valid_gen = kvm->arch.mmu_valid_gen; + list_add(&sp->link, &kvm->arch.active_mmu_pages); + kvm_mod_used_mmu_pages(kvm, +1); sp->gfn = gfn; sp->role = role; hlist_add_head(&sp->hash_link, sp_list); if (!role.direct) - account_shadowed(vcpu->kvm, sp); + account_shadowed(kvm, sp); return sp; } @@ -2132,7 +2132,7 @@ static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, sp = kvm_mmu_find_shadow_page(vcpu, gfn, sp_list, role); if (!sp) { created = true; - sp = kvm_mmu_alloc_shadow_page(vcpu, caches, gfn, sp_list, role); + sp = kvm_mmu_alloc_shadow_page(vcpu->kvm, caches, gfn, sp_list, role); } trace_kvm_mmu_get_page(sp, created); From patchwork Fri Apr 22 21:05:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824165 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 95C52C433EF for ; Fri, 22 Apr 2022 22:13:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232388AbiDVWQs (ORCPT ); Fri, 22 Apr 2022 18:16:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232057AbiDVWPh (ORCPT ); Fri, 22 Apr 2022 18:15:37 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EE21731A152 for ; Fri, 22 Apr 2022 14:06:04 -0700 (PDT) Received: by mail-pl1-x64a.google.com with SMTP id z5-20020a170902ccc500b0015716eaec65so5386835ple.14 for ; Fri, 22 Apr 2022 14:06:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=eu8VJbJguY6ZXLXdguLoPmTx5E277sRGDrrNJcFdDls=; b=mm+KqjDQ8J0VSRw/QbSRolONpDUykCEYi89d8db8fl+iMViZR8v5A2X+QebpfJFc6B C8OURrG9LEQ4a3Wytvf4Ke9Q4CLrkDEndf5ycAdjvcdDkpbRxN0Yl+KrHS7izEFDlTwz c60cSQk5zb2UrX23tjZkqU3oH6gqEVS09yNyvaqqAH1hcARFFV1SltSJ/hCHEk8urLQl aRxdC99NmJrI6wfB5XGr20cRyUEx0oF3aql6vDmSs5mcnQ4VKFMevlqhMefHONh7+Oxk PfA3mhq70dtJJldDxC9vfyjDn822V20AWlkPT4ytIG7T7bQaaHlOPvaTeK89XHUFktN4 Evtw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=eu8VJbJguY6ZXLXdguLoPmTx5E277sRGDrrNJcFdDls=; b=rvYUxNuGtf5E4U7ujtG5LvNArlekUMMIi4coaanZKkQfcy8iAuuuagWG9WYQ6vvn8/ L5ieUrUAzIX8qmZAKr6QSksXWJw+GnNum/ItzjZC2D4wm9IeoUOZWeT//oiOahGNFbYo 74gJmYsWq266F6sEsp7eu8mLhTSnEvIQ5YxvicUFqmDx+00Vw00hRK0vW431FSKF9r6T 8Kdgo2aJI3GXTbf2aKkyzDhTHc8dofzHzz9L030KMMq67GPCd3/r3XlyWuHgimSucJAp oIA7DkzfqrbZ4pS7snavMS59i4d9ZQwAaAterhp9bTM83Qu0F3OUWKVPEdr2c1wX7NK5 XvGA== X-Gm-Message-State: AOAM531XKE+lpqyAmttTMDhgYug7/93je/wnZj4FdlzAHpPtcHEkoFtr 3W0fjIraSlu0Mdvx1GLjUq2Niq1g2FubsA== X-Google-Smtp-Source: ABdhPJzGn8bnFbc/Hfs0LpuWfl2EI/jAUqlaxIL7OMkYkvAkhScJ3fiquDkJMS7/S7081qV96um484xUT08c2g== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:902:e803:b0:15c:e281:de8f with SMTP id u3-20020a170902e80300b0015ce281de8fmr838250plg.13.1650661564401; Fri, 22 Apr 2022 14:06:04 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:36 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-11-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 10/20] KVM: x86/mmu: Pass kvm pointer separately from vcpu to kvm_mmu_find_shadow_page() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Get the kvm pointer from the caller, rather than deriving it from vcpu->kvm, and plumb the kvm pointer all the way from kvm_mmu_get_shadow_page(). With this change in place, the vcpu pointer is only needed to sync indirect shadow pages. In other words, __kvm_mmu_get_shadow_page() can now be used to get *direct* shadow pages without a vcpu pointer. This enables eager page splitting, which needs to allocate direct shadow pages during VM ioctls. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index df110e0d57cf..04029c01aebd 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2003,7 +2003,8 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sptep_to_sp(spte)); } -static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, +static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm, + struct kvm_vcpu *vcpu, gfn_t gfn, struct hlist_head *sp_list, union kvm_mmu_page_role role) @@ -2013,7 +2014,7 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, int collisions = 0; LIST_HEAD(invalid_list); - for_each_valid_sp(vcpu->kvm, sp, sp_list) { + for_each_valid_sp(kvm, sp, sp_list) { if (sp->gfn != gfn) { collisions++; continue; @@ -2030,7 +2031,7 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, * upper-level page will be write-protected. */ if (role.level > PG_LEVEL_4K && sp->unsync) - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, + kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); continue; } @@ -2058,7 +2059,7 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, WARN_ON(!list_empty(&invalid_list)); if (ret > 0) - kvm_flush_remote_tlbs(vcpu->kvm); + kvm_flush_remote_tlbs(kvm); } __clear_sp_write_flooding_count(sp); @@ -2067,13 +2068,13 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm_vcpu *vcpu, } sp = NULL; - ++vcpu->kvm->stat.mmu_cache_miss; + ++kvm->stat.mmu_cache_miss; out: - kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list); + kvm_mmu_commit_zap_page(kvm, &invalid_list); - if (collisions > vcpu->kvm->stat.max_mmu_page_hash_collisions) - vcpu->kvm->stat.max_mmu_page_hash_collisions = collisions; + if (collisions > kvm->stat.max_mmu_page_hash_collisions) + kvm->stat.max_mmu_page_hash_collisions = collisions; return sp; } @@ -2118,7 +2119,8 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, return sp; } -static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, +static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm, + struct kvm_vcpu *vcpu, struct shadow_page_caches *caches, gfn_t gfn, union kvm_mmu_page_role role) @@ -2127,12 +2129,12 @@ static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp; bool created = false; - sp_list = &vcpu->kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; - sp = kvm_mmu_find_shadow_page(vcpu, gfn, sp_list, role); + sp = kvm_mmu_find_shadow_page(kvm, vcpu, gfn, sp_list, role); if (!sp) { created = true; - sp = kvm_mmu_alloc_shadow_page(vcpu->kvm, caches, gfn, sp_list, role); + sp = kvm_mmu_alloc_shadow_page(kvm, caches, gfn, sp_list, role); } trace_kvm_mmu_get_page(sp, created); @@ -2149,7 +2151,7 @@ static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, .gfn_array_cache = &vcpu->arch.mmu_gfn_array_cache, }; - return __kvm_mmu_get_shadow_page(vcpu, &caches, gfn, role); + return __kvm_mmu_get_shadow_page(vcpu->kvm, vcpu, &caches, gfn, role); } static union kvm_mmu_page_role kvm_mmu_child_role(u64 *sptep, bool direct, u32 access) From patchwork Fri Apr 22 21:05:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824149 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D22ABC433EF for ; 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Fri, 22 Apr 2022 14:06:06 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:37 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-12-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 11/20] KVM: x86/mmu: Allow for NULL vcpu pointer in __kvm_mmu_get_shadow_page() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Allow the vcpu pointer in __kvm_mmu_get_shadow_page() to be NULL. Rename it to vcpu_or_null to prevent future commits from accidentally taking dependency on it without first considering the NULL case. The vcpu pointer is only used for syncing indirect shadow pages in kvm_mmu_find_shadow_page(). A vcpu pointer it not required for correctness since unsync pages can simply be zapped. But this should never occur in practice, since the only use-case for passing a NULL vCPU pointer is eager page splitting which will only request direct shadow pages (which can never be unsync). Even though __kvm_mmu_get_shadow_page() can gracefully handle a NULL vcpu, add a WARN() that will fire if __kvm_mmu_get_shadow_page() is ever called to get an indirect shadow page with a NULL vCPU pointer, since zapping unsync SPs is a performance overhead that should be considered. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 40 ++++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 04029c01aebd..21407bd4435a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1845,16 +1845,27 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)]) \ if ((_sp)->gfn != (_gfn) || (_sp)->role.direct) {} else -static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, - struct list_head *invalid_list) +static int __kvm_sync_page(struct kvm *kvm, struct kvm_vcpu *vcpu_or_null, + struct kvm_mmu_page *sp, + struct list_head *invalid_list) { - int ret = vcpu->arch.mmu->sync_page(vcpu, sp); + int ret = -1; + + if (vcpu_or_null) + ret = vcpu_or_null->arch.mmu->sync_page(vcpu_or_null, sp); if (ret < 0) - kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list); + kvm_mmu_prepare_zap_page(kvm, sp, invalid_list); + return ret; } +static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, + struct list_head *invalid_list) +{ + return __kvm_sync_page(vcpu->kvm, vcpu, sp, invalid_list); +} + static bool kvm_mmu_remote_flush_or_zap(struct kvm *kvm, struct list_head *invalid_list, bool remote_flush) @@ -2004,7 +2015,7 @@ static void clear_sp_write_flooding_count(u64 *spte) } static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm, - struct kvm_vcpu *vcpu, + struct kvm_vcpu *vcpu_or_null, gfn_t gfn, struct hlist_head *sp_list, union kvm_mmu_page_role role) @@ -2053,7 +2064,7 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm, * If the sync fails, the page is zapped. If so, break * in order to rebuild it. */ - ret = kvm_sync_page(vcpu, sp, &invalid_list); + ret = __kvm_sync_page(kvm, vcpu_or_null, sp, &invalid_list); if (ret < 0) break; @@ -2120,7 +2131,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, } static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm, - struct kvm_vcpu *vcpu, + struct kvm_vcpu *vcpu_or_null, struct shadow_page_caches *caches, gfn_t gfn, union kvm_mmu_page_role role) @@ -2129,9 +2140,22 @@ static struct kvm_mmu_page *__kvm_mmu_get_shadow_page(struct kvm *kvm, struct kvm_mmu_page *sp; bool created = false; + /* + * A vCPU pointer should always be provided when getting indirect + * shadow pages, as that shadow page may already exist and need to be + * synced using the vCPU pointer (see __kvm_sync_page()). Direct shadow + * pages are never unsync and thus do not require a vCPU pointer. + * + * No need to panic here as __kvm_sync_page() falls back to zapping an + * unsync page if the vCPU pointer is NULL. But still WARN() since + * such zapping will impact performance and this situation is never + * expected to occur in practice. + */ + WARN_ON(!vcpu_or_null && !role.direct); + sp_list = &kvm->arch.mmu_page_hash[kvm_page_table_hashfn(gfn)]; - sp = kvm_mmu_find_shadow_page(kvm, vcpu, gfn, sp_list, role); + sp = kvm_mmu_find_shadow_page(kvm, vcpu_or_null, gfn, sp_list, role); if (!sp) { created = true; sp = kvm_mmu_alloc_shadow_page(kvm, caches, gfn, sp_list, role); From patchwork Fri Apr 22 21:05:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824164 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F231C433F5 for ; Fri, 22 Apr 2022 22:13:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232544AbiDVWQr (ORCPT ); Fri, 22 Apr 2022 18:16:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232447AbiDVWPh (ORCPT ); Fri, 22 Apr 2022 18:15:37 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD05F31A163 for ; Fri, 22 Apr 2022 14:06:08 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id q13-20020a638c4d000000b003821725ad66so5625461pgn.23 for ; Fri, 22 Apr 2022 14:06:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=K3CLnYXYtvwizIx0k/SHLSP8rSxb5Vb9/+Ons8DtsNg=; b=l2jbmncxyjqZKtjNxBwQjGGI5g04tJzYsGlUZdx53H4OmCl7Mb8VVw6NQr06/u5sIm t7o9fZY1KQubggYso4Hk8sVINmzelJOkDXmo4A3b0OvzrgMUHpJfM5GxpywlO8GiaglK boESpTsBCImRP9pHIN6HhIgSF8AVf860FSrJpiJk5cCfpoMa8Uutbu1v1IJjbjHKip5P OmoUnN2F8FYsQ9FiQJc5WB5DzQ4wQW5qYVEoc2/ebZ6AAXM7SCjgglwzsMQFgp/GNklH 4O8m1AQ4dX5M6yymiWkhpE5eycUOVcGs06KWM6JBv7y+h9hHVc2cO/wykNVd1YFzJahw gK3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=K3CLnYXYtvwizIx0k/SHLSP8rSxb5Vb9/+Ons8DtsNg=; b=Ri9disfRjbiZf5a6mveaGet5o2gq/SvOMY51u2qSFUGNF0ZuFRTtAspR93qYACpiH8 PrFxJQ0m5OuZ+OEzn2QlSSbIO+duudOar+CjzABO06/ciMEqh8CoTDV+ALN7fb7fXn24 NUSqKxXKZZMf+9IKzkaWo9zgkrMLA4qkcexUfoRgzuDShlmZkhutMa6lbqss0m5L4yw3 vkniOXCX3McDFpZlzariUD91rOPc49iD/VmDYOKLdFgQ6AmImJuQ9qPx0p0+XSa7BUB7 vaa4vXI0RedIzHF7SURhKhnCqox205+l3DXmxuITDPM31+fcQSNl64QjSoAPfm9+3bdO oPeg== X-Gm-Message-State: AOAM531cFD+eZmrR+ueA21PGKM1Y40iKCdiKNjC1AGnVbOBHkoocG3IH ERkJqlLDKJjlN7VfzY7pOPhGi+KKaCzmeA== X-Google-Smtp-Source: ABdhPJxo16FW5saOeBbKmUkcRSzAGnKKyvc+JzAJ2fwc+QXYy7JIR3KSk+h5wZyUpeyuzG8nBdVfN7Odw8S7VQ== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:90a:9105:b0:1d2:9e98:7e1e with SMTP id k5-20020a17090a910500b001d29e987e1emr620451pjo.0.1650661567820; Fri, 22 Apr 2022 14:06:07 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:38 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-13-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 12/20] KVM: x86/mmu: Pass const memslot to rmap_add() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org rmap_add() only uses the slot to call gfn_to_rmap() which takes a const memslot. No functional change intended. Reviewed-by: Ben Gardon Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 21407bd4435a..142c2f357f1b 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1595,7 +1595,7 @@ static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, #define RMAP_RECYCLE_THRESHOLD 1000 -static void rmap_add(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, +static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, u64 *spte, gfn_t gfn) { struct kvm_mmu_page *sp; From patchwork Fri Apr 22 21:05:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824163 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33C84C433EF for ; Fri, 22 Apr 2022 22:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232605AbiDVWQp (ORCPT ); Fri, 22 Apr 2022 18:16:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45546 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232444AbiDVWPh (ORCPT ); Fri, 22 Apr 2022 18:15:37 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD5E331A16E for ; Fri, 22 Apr 2022 14:06:10 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id d5-20020a62f805000000b0050566b4f4c0so6108016pfh.11 for ; Fri, 22 Apr 2022 14:06:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=fDlC1IpGHWaDDqsCJTKlfaJK8Ikyh2hh3RLE6Uw8w48=; b=GAf3oRX3uCpKdZWEkPoWsjY0kJA7tYFdV61LT9rz8Tc2ihn/1UymnNmVQ/OzWL9Rpa cq+rgMB0eXbebaWU2Be08WmLGF6idAHBwkSmh/29aur5BSnC3EuOslmT3vitL7hbnb9S gT4TU7EqjnSEZlDfOgiTObDdpOYIe2MsVUCGqV1pqk9i0TcSO5wcF6OMY9BKBGCiTlY3 CRF7SyfhROGBudmslOSIkdb60P5MbwMG7jur1YwUrtBsRjhhw8Oj2NcEagP1rtHwujAt mJqIZLfQvhJBMtNBKxFDHolSfbhZT9pfT2xKOJ5qaDTOradCYv8qwFPXIDVLvUYSW+/C Uvtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fDlC1IpGHWaDDqsCJTKlfaJK8Ikyh2hh3RLE6Uw8w48=; b=0WQ4dFAPxRrYu7JYSPueWTZWDgLsx7kCdHjhsEZBzPyqD4np+dBodzLUk+C0kkgGfW tIDCa4ZNmUNgXpNQz7IysJFO6MMJ3AjeO8VPADgjhqRisGjgMtAAm0+sGndDgAIy+0zC 2/5IfF2LS+hHG2AOnIUxKThjYrE4OuGPNJK5N4UmWOynudZkW3dtyD/FSxM+5j81VRyY /6NtU9DQNf8+sBStMSLnnfFA6FOFtX8J18D1FqkqaTQyJgYpV0htiUQ+5GydAS+GVh0K udB2PnnWqj68LU2xJ4/DSLnWz+yy3W9wR4uNLRyvG020EgKOhzZ0Gaui0oGr4fPmPeEU 3DiQ== X-Gm-Message-State: AOAM532VTIQ235ZezaXnWIGYSbxv2jsufkwwXTeqgwhNhXXvi0X/b6MR U4gqVekvo4l4v3H0w0LgToaYFyCdcKgmOA== X-Google-Smtp-Source: ABdhPJyQk4t75EKl4QuajygSUJHNhIl7lEQ70BarQVctsEKaG3ASWLqcJ0dezwzSCbcJLM2yaXgIlPVEs67dRA== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:90b:2384:b0:1cb:5223:9dc4 with SMTP id mr4-20020a17090b238400b001cb52239dc4mr620746pjb.1.1650661569546; Fri, 22 Apr 2022 14:06:09 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:39 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-14-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 13/20] KVM: x86/mmu: Decouple rmap_add() and link_shadow_page() from kvm_vcpu From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Allow adding new entries to the rmap and linking shadow pages without a struct kvm_vcpu pointer by moving the implementation of rmap_add() and link_shadow_page() into inner helper functions. No functional change intended. Reviewed-by: Ben Gardon Reviewed-by: Peter Xu Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 44 +++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 18 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 142c2f357f1b..ed23782eef8a 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -722,11 +722,6 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache); } -static struct pte_list_desc *mmu_alloc_pte_list_desc(struct kvm_vcpu *vcpu) -{ - return kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_pte_list_desc_cache); -} - static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc) { kmem_cache_free(pte_list_desc_cache, pte_list_desc); @@ -873,7 +868,7 @@ gfn_to_memslot_dirty_bitmap(struct kvm_vcpu *vcpu, gfn_t gfn, /* * Returns the number of pointers in the rmap chain, not counting the new one. */ -static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, +static int pte_list_add(struct kvm_mmu_memory_cache *cache, u64 *spte, struct kvm_rmap_head *rmap_head) { struct pte_list_desc *desc; @@ -884,7 +879,7 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, rmap_head->val = (unsigned long)spte; } else if (!(rmap_head->val & 1)) { rmap_printk("%p %llx 1->many\n", spte, *spte); - desc = mmu_alloc_pte_list_desc(vcpu); + desc = kvm_mmu_memory_cache_alloc(cache); desc->sptes[0] = (u64 *)rmap_head->val; desc->sptes[1] = spte; desc->spte_count = 2; @@ -896,7 +891,7 @@ static int pte_list_add(struct kvm_vcpu *vcpu, u64 *spte, while (desc->spte_count == PTE_LIST_EXT) { count += PTE_LIST_EXT; if (!desc->more) { - desc->more = mmu_alloc_pte_list_desc(vcpu); + desc->more = kvm_mmu_memory_cache_alloc(cache); desc = desc->more; desc->spte_count = 0; break; @@ -1595,8 +1590,10 @@ static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, #define RMAP_RECYCLE_THRESHOLD 1000 -static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, - u64 *spte, gfn_t gfn) +static void __rmap_add(struct kvm *kvm, + struct kvm_mmu_memory_cache *cache, + const struct kvm_memory_slot *slot, + u64 *spte, gfn_t gfn) { struct kvm_mmu_page *sp; struct kvm_rmap_head *rmap_head; @@ -1605,15 +1602,21 @@ static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, sp = sptep_to_sp(spte); kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); rmap_head = gfn_to_rmap(gfn, sp->role.level, slot); - rmap_count = pte_list_add(vcpu, spte, rmap_head); + rmap_count = pte_list_add(cache, spte, rmap_head); if (rmap_count > RMAP_RECYCLE_THRESHOLD) { - kvm_unmap_rmapp(vcpu->kvm, rmap_head, NULL, gfn, sp->role.level, __pte(0)); + kvm_unmap_rmapp(kvm, rmap_head, NULL, gfn, sp->role.level, __pte(0)); kvm_flush_remote_tlbs_with_address( - vcpu->kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); + kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); } } +static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, + u64 *spte, gfn_t gfn) +{ + __rmap_add(vcpu->kvm, &vcpu->arch.mmu_pte_list_desc_cache, slot, spte, gfn); +} + bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) { bool young = false; @@ -1684,13 +1687,13 @@ static unsigned kvm_page_table_hashfn(gfn_t gfn) return hash_64(gfn, KVM_MMU_HASH_SHIFT); } -static void mmu_page_add_parent_pte(struct kvm_vcpu *vcpu, +static void mmu_page_add_parent_pte(struct kvm_mmu_memory_cache *cache, struct kvm_mmu_page *sp, u64 *parent_pte) { if (!parent_pte) return; - pte_list_add(vcpu, parent_pte, &sp->parent_ptes); + pte_list_add(cache, parent_pte, &sp->parent_ptes); } static void mmu_page_remove_parent_pte(struct kvm_mmu_page *sp, @@ -2286,8 +2289,8 @@ static void shadow_walk_next(struct kvm_shadow_walk_iterator *iterator) __shadow_walk_next(iterator, *iterator->sptep); } -static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, - struct kvm_mmu_page *sp) +static void __link_shadow_page(struct kvm_mmu_memory_cache *cache, u64 *sptep, + struct kvm_mmu_page *sp) { u64 spte; @@ -2297,12 +2300,17 @@ static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, mmu_spte_set(sptep, spte); - mmu_page_add_parent_pte(vcpu, sp, sptep); + mmu_page_add_parent_pte(cache, sp, sptep); if (sp->unsync_children || sp->unsync) mark_unsync(sptep); } +static void link_shadow_page(struct kvm_vcpu *vcpu, u64 *sptep, struct kvm_mmu_page *sp) +{ + __link_shadow_page(&vcpu->arch.mmu_pte_list_desc_cache, sptep, sp); +} + static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned direct_access) { From patchwork Fri Apr 22 21:05:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824156 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81CA7C4332F for ; Fri, 22 Apr 2022 22:13:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232541AbiDVWQP (ORCPT ); Fri, 22 Apr 2022 18:16:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232301AbiDVWPi (ORCPT ); Fri, 22 Apr 2022 18:15:38 -0400 Received: from mail-oo1-xc49.google.com (mail-oo1-xc49.google.com [IPv6:2607:f8b0:4864:20::c49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D48D226096 for ; 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Fri, 22 Apr 2022 14:06:11 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:40 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-15-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 14/20] KVM: x86/mmu: Update page stats in __rmap_add() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Update the page stats in __rmap_add() rather than at the call site. This will avoid having to manually update page stats when splitting huge pages in a subsequent commit. No functional change intended. Reviewed-by: Ben Gardon Reviewed-by: Peter Xu Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index ed23782eef8a..6a190fe6c9dc 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1601,6 +1601,8 @@ static void __rmap_add(struct kvm *kvm, sp = sptep_to_sp(spte); kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); + kvm_update_page_stats(kvm, sp->role.level, 1); + rmap_head = gfn_to_rmap(gfn, sp->role.level, slot); rmap_count = pte_list_add(cache, spte, rmap_head); @@ -2818,7 +2820,6 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, if (!was_rmapped) { WARN_ON_ONCE(ret == RET_PF_SPURIOUS); - kvm_update_page_stats(vcpu->kvm, level, 1); rmap_add(vcpu, slot, sptep, gfn); } From patchwork Fri Apr 22 21:05:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824157 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B13B4C433EF for ; Fri, 22 Apr 2022 22:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232223AbiDVWQT (ORCPT ); Fri, 22 Apr 2022 18:16:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232475AbiDVWPj (ORCPT ); Fri, 22 Apr 2022 18:15:39 -0400 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD4BB23E816 for ; Fri, 22 Apr 2022 14:06:13 -0700 (PDT) Received: by mail-pf1-x44a.google.com with SMTP id 15-20020aa7920f000000b0050cf449957fso1434264pfo.9 for ; Fri, 22 Apr 2022 14:06:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=KFu74/1LFhYChFVRV8yYV2rmiovnNzZUI5NGAy6n7ps=; b=RelD8PTSw3o9B+IoxLY+GZlM1L3aDBoAxfWyQxrK6eB/hGlLL6YDQP4zVqB3oR2jC3 zYW3kf5P8SmI74uAlY4hIalp9MWjko5koBnoTHfbUvkXU8b1JSjqpp+Q7dsHnPf3cBJQ JiB8+wUE+3p41u3CenAbQmuoILBTCx/SNr0eR8LtQKjoLgJftlodn091mcWNYMDXj8bi R8/TEJ6lLShd6JnI/2q8AHVSARwJGFKFb6//E5iBlylUdX0vZ3m5n2JJcXf/fCM/ULFx PeRjRHxLjADVDw9ZwSEmyBsvOvGKz5FtMlA4MWqNxy5FhgiE2JiAWYaQlY3tr3hvGb1f e3kQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=KFu74/1LFhYChFVRV8yYV2rmiovnNzZUI5NGAy6n7ps=; b=bItVpjtDHnPwLvK9b6QWJnswJtNmOwuDO0XLoNUBIKUbucnuuT32/EXc0QvKSOUAqS Hki3ASfMQSuXbc6UOb+Suc/Q8gni5UPHCDes33DbGzb7FLWiYEu8x8+p6XozDjThKkbk xjgYrOJObWRaAbOY5gSrNey4s8FbKYdep/B5FjiT1Z67PbytIC6vyFRr39g79tyGrmHx Y7a1yUk0mLMfFEiqzfgkNPbbFBppa7D5GNS08nHbh9NQHYy4IDOJaanflkMZitTwGdMx Zt9HtBe24O8lJgizHG1eIk93p/ksRa0C36fHPI0ADcmJ6ZzcHrKC2AV5ANBJGtuIx8Pt PmyA== X-Gm-Message-State: AOAM531PZOzbm0gdQ1vDm0Otbhb+5b7nrsof/qRE9s8j0j1TxJeyfUED DSErGYAJvoYkFnis0pJg6hia2h2okRuX4Q== X-Google-Smtp-Source: ABdhPJxdUvTORycpTm6+ENI526zs84Kfta+yDMJOj54qZB8CfK2s6LN0IRAw4LqFKnALMmjXx9sPpUvh+Cx2DA== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a63:591c:0:b0:3aa:506c:b50b with SMTP id n28-20020a63591c000000b003aa506cb50bmr5494405pgb.77.1650661573164; Fri, 22 Apr 2022 14:06:13 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:41 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-16-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 15/20] KVM: x86/mmu: Cache the access bits of shadowed translations From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Splitting huge pages requires allocating/finding shadow pages to replace the huge page. Shadow pages are keyed, in part, off the guest access permissions they are shadowing. For fully direct MMUs, there is no shadowing so the access bits in the shadow page role are always ACC_ALL. But during shadow paging, the guest can enforce whatever access permissions it wants. When KVM is resolving a fault, it walks the guest pages tables to determine the guest access permissions. But that is difficult to plumb when splitting huge pages outside of a fault context, e.g. for eager page splitting. To enable eager page splitting, KVM can cache the shadowed (guest) access permissions whenever it updates the shadow page tables (e.g. during fault, or FNAME(sync_page)). In fact KVM already does this to cache the shadowed GFN using the gfns array in the shadow page. The access bits only take up 3 bits, which leaves 61 bits left over for gfns, which is more than enough. So this change does not require any additional memory. Now that the gfns array caches more information than just GFNs, rename it to shadowed_translation. While here, preemptively fix up the WARN_ON() that detects gfn mismatches in direct SPs. The WARN_ON() was paired with a pr_err_ratelimited(), which means that users could sometimes see the WARN without the accompanying error message. Fix this by outputting the error message as part of the WARN splat. Signed-off-by: David Matlack --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/mmu/mmu.c | 82 +++++++++++++++++++++++++-------- arch/x86/kvm/mmu/mmu_internal.h | 17 ++++++- arch/x86/kvm/mmu/paging_tmpl.h | 8 +++- 4 files changed, 85 insertions(+), 24 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 2c20f715f009..15131aa05701 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -691,7 +691,7 @@ struct kvm_vcpu_arch { struct kvm_mmu_memory_cache mmu_pte_list_desc_cache; struct kvm_mmu_memory_cache mmu_shadow_page_cache; - struct kvm_mmu_memory_cache mmu_gfn_array_cache; + struct kvm_mmu_memory_cache mmu_shadowed_info_cache; struct kvm_mmu_memory_cache mmu_page_header_cache; /* diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 6a190fe6c9dc..ed65899d15a2 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -705,7 +705,7 @@ static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu, bool maybe_indirect) if (r) return r; if (maybe_indirect) { - r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_gfn_array_cache, + r = kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_shadowed_info_cache, PT64_ROOT_MAX_LEVEL); if (r) return r; @@ -718,7 +718,7 @@ static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) { kvm_mmu_free_memory_cache(&vcpu->arch.mmu_pte_list_desc_cache); kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadow_page_cache); - kvm_mmu_free_memory_cache(&vcpu->arch.mmu_gfn_array_cache); + kvm_mmu_free_memory_cache(&vcpu->arch.mmu_shadowed_info_cache); kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_header_cache); } @@ -730,23 +730,64 @@ static void mmu_free_pte_list_desc(struct pte_list_desc *pte_list_desc) static gfn_t kvm_mmu_page_get_gfn(struct kvm_mmu_page *sp, int index) { if (!sp->role.direct) - return sp->gfns[index]; + return sp->shadowed_translation[index] >> PAGE_SHIFT; return sp->gfn + (index << ((sp->role.level - 1) * PT64_LEVEL_BITS)); } -static void kvm_mmu_page_set_gfn(struct kvm_mmu_page *sp, int index, gfn_t gfn) +static void kvm_mmu_page_set_access(struct kvm_mmu_page *sp, int index, u32 access) { if (!sp->role.direct) { - sp->gfns[index] = gfn; + sp->shadowed_translation[index] &= PAGE_MASK; + sp->shadowed_translation[index] |= access; return; } - if (WARN_ON(gfn != kvm_mmu_page_get_gfn(sp, index))) - pr_err_ratelimited("gfn mismatch under direct page %llx " - "(expected %llx, got %llx)\n", - sp->gfn, - kvm_mmu_page_get_gfn(sp, index), gfn); + WARN(access != sp->role.access, + "access mismatch under direct page %llx (expected %u, got %u)\n", + sp->gfn, sp->role.access, access); +} + +static void kvm_mmu_page_set_translation(struct kvm_mmu_page *sp, int index, gfn_t gfn, u32 access) +{ + if (!sp->role.direct) { + sp->shadowed_translation[index] = (gfn << PAGE_SHIFT) | access; + return; + } + + WARN(access != sp->role.access, + "access mismatch under direct page %llx (expected %u, got %u)\n", + sp->gfn, sp->role.access, access); + + WARN(gfn != kvm_mmu_page_get_gfn(sp, index), + "gfn mismatch under direct page %llx (expected %llx, got %llx)\n", + sp->gfn, kvm_mmu_page_get_gfn(sp, index), gfn); +} + +/* + * For leaf SPTEs, fetch the *guest* access permissions being shadowed. Note + * that the SPTE itself may have a more constrained access permissions that + * what the guest enforces. For example, a guest may create an executable + * huge PTE but KVM may disallow execution to mitigate iTLB multihit. + */ +static u32 kvm_mmu_page_get_access(struct kvm_mmu_page *sp, int index) +{ + if (!sp->role.direct) + return sp->shadowed_translation[index] & ACC_ALL; + + /* + * For direct MMUs (e.g. TDP or non-paging guests) there are no *guest* + * access permissions being shadowed, which is equivalent to ACC_ALL. + * + * For indirect MMUs (shadow paging), direct shadow pages exist when KVM + * is shadowing a guest huge page with smaller pages, since the guest + * huge page is being directly mapped. In this case the guest access + * permissions being shadowed are the access permissions of the huge + * page. + * + * In both cases, sp->role.access contains the correct access bits. + */ + return sp->role.access; } /* @@ -1593,14 +1634,14 @@ static bool kvm_test_age_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head, static void __rmap_add(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, const struct kvm_memory_slot *slot, - u64 *spte, gfn_t gfn) + u64 *spte, gfn_t gfn, u32 access) { struct kvm_mmu_page *sp; struct kvm_rmap_head *rmap_head; int rmap_count; sp = sptep_to_sp(spte); - kvm_mmu_page_set_gfn(sp, spte - sp->spt, gfn); + kvm_mmu_page_set_translation(sp, spte - sp->spt, gfn, access); kvm_update_page_stats(kvm, sp->role.level, 1); rmap_head = gfn_to_rmap(gfn, sp->role.level, slot); @@ -1614,9 +1655,9 @@ static void __rmap_add(struct kvm *kvm, } static void rmap_add(struct kvm_vcpu *vcpu, const struct kvm_memory_slot *slot, - u64 *spte, gfn_t gfn) + u64 *spte, gfn_t gfn, u32 access) { - __rmap_add(vcpu->kvm, &vcpu->arch.mmu_pte_list_desc_cache, slot, spte, gfn); + __rmap_add(vcpu->kvm, &vcpu->arch.mmu_pte_list_desc_cache, slot, spte, gfn, access); } bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) @@ -1680,7 +1721,7 @@ static void kvm_mmu_free_shadow_page(struct kvm_mmu_page *sp) list_del(&sp->link); free_page((unsigned long)sp->spt); if (!sp->role.direct) - free_page((unsigned long)sp->gfns); + free_page((unsigned long)sp->shadowed_translation); kmem_cache_free(mmu_page_header_cache, sp); } @@ -2098,7 +2139,7 @@ static struct kvm_mmu_page *kvm_mmu_find_shadow_page(struct kvm *kvm, struct shadow_page_caches { struct kvm_mmu_memory_cache *page_header_cache; struct kvm_mmu_memory_cache *shadow_page_cache; - struct kvm_mmu_memory_cache *gfn_array_cache; + struct kvm_mmu_memory_cache *shadowed_info_cache; }; static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, @@ -2112,7 +2153,7 @@ static struct kvm_mmu_page *kvm_mmu_alloc_shadow_page(struct kvm *kvm, sp = kvm_mmu_memory_cache_alloc(caches->page_header_cache); sp->spt = kvm_mmu_memory_cache_alloc(caches->shadow_page_cache); if (!role.direct) - sp->gfns = kvm_mmu_memory_cache_alloc(caches->gfn_array_cache); + sp->shadowed_translation = kvm_mmu_memory_cache_alloc(caches->shadowed_info_cache); set_page_private(virt_to_page(sp->spt), (unsigned long)sp); @@ -2177,7 +2218,7 @@ static struct kvm_mmu_page *kvm_mmu_get_shadow_page(struct kvm_vcpu *vcpu, struct shadow_page_caches caches = { .page_header_cache = &vcpu->arch.mmu_page_header_cache, .shadow_page_cache = &vcpu->arch.mmu_shadow_page_cache, - .gfn_array_cache = &vcpu->arch.mmu_gfn_array_cache, + .shadowed_info_cache = &vcpu->arch.mmu_shadowed_info_cache, }; return __kvm_mmu_get_shadow_page(vcpu->kvm, vcpu, &caches, gfn, role); @@ -2820,7 +2861,10 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot, if (!was_rmapped) { WARN_ON_ONCE(ret == RET_PF_SPURIOUS); - rmap_add(vcpu, slot, sptep, gfn); + rmap_add(vcpu, slot, sptep, gfn, pte_access); + } else { + /* Already rmapped but the pte_access bits may have changed. */ + kvm_mmu_page_set_access(sp, sptep - sp->spt, pte_access); } return ret; diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h index 1bff453f7cbe..1614a577a1cb 100644 --- a/arch/x86/kvm/mmu/mmu_internal.h +++ b/arch/x86/kvm/mmu/mmu_internal.h @@ -53,8 +53,21 @@ struct kvm_mmu_page { gfn_t gfn; u64 *spt; - /* hold the gfn of each spte inside spt */ - gfn_t *gfns; + + /* + * Stores the result of the guest translation being shadowed by each + * SPTE. KVM shadows two types of guest translations: nGPA -> GPA + * (shadow EPT/NPT) and GVA -> GPA (traditional shadow paging). In both + * cases the result of the translation is a GPA and a set of access + * constraints. + * + * The GFN is stored in the upper bits (PAGE_SHIFT) and the shadowed + * access permissions are stored in the lower bits. Note, for + * convenience and uniformity across guests, the access permissions are + * stored in KVM format (e.g. ACC_EXEC_MASK) not the raw guest format. + */ + u64 *shadowed_translation; + /* Currently serving as active root */ union { int root_count; diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h index a8a755e1561d..97bf53b29b88 100644 --- a/arch/x86/kvm/mmu/paging_tmpl.h +++ b/arch/x86/kvm/mmu/paging_tmpl.h @@ -978,7 +978,8 @@ static gpa_t FNAME(gva_to_gpa)(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, } /* - * Using the cached information from sp->gfns is safe because: + * Using the information in sp->shadowed_translation (kvm_mmu_page_get_gfn() + * and kvm_mmu_page_get_access()) is safe because: * - The spte has a reference to the struct page, so the pfn for a given gfn * can't change unless all sptes pointing to it are nuked first. * @@ -1052,12 +1053,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp) if (sync_mmio_spte(vcpu, &sp->spt[i], gfn, pte_access)) continue; - if (gfn != sp->gfns[i]) { + if (gfn != kvm_mmu_page_get_gfn(sp, i)) { drop_spte(vcpu->kvm, &sp->spt[i]); flush = true; continue; } + if (pte_access != kvm_mmu_page_get_access(sp, i)) + kvm_mmu_page_set_access(sp, i, pte_access); + sptep = &sp->spt[i]; spte = *sptep; host_writable = spte & shadow_host_writable_mask; From patchwork Fri Apr 22 21:05:42 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824162 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABE83C433F5 for ; Fri, 22 Apr 2022 22:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232055AbiDVWQl (ORCPT ); Fri, 22 Apr 2022 18:16:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232480AbiDVWPj (ORCPT ); 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d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=z0XSCH07in75tEpUNZM8MYk8qU4dimko+wjHO05t1Es=; b=ptHd1aI75w1spoUVEuzHyPE476X3KU7fDCoaJ+QJnS5M4Mus68KmjPUCz3RcWqPp5g SZNZ97IEVccv20x+0pao8sceecYsM676AAb9Adzwo3rqi6CCU0M3hJnwNZq+FPekrfI/ Il5wxfKejpHJk3nHPWoomHeSZP7Tw3VTdlEF48R4UVlTJmQQ5KaS7kPrXiWXGD3nBUnE g63I76jM4cNh1BXljzbWxPCYubziAjeFAKpmBC6FBkrvxp3HHmcVqdpkjwfr/u61rcVB VpLPxKotbV0EDEN2WKVy8n/NlIppmzRQRzZS7FaXXMWVpwcBwn72Q/cyGwAZ8BeXiF3G lmcg== X-Gm-Message-State: AOAM532R+1kxcPRHT+4SIRfbzl/+7+hDcl86FRZtQUTtaDtwfpotFc/O sNyx7njIKUSgXbw/VeLGsUgh/Hc7e5u9xA== X-Google-Smtp-Source: ABdhPJxZKsBJ5rApfD6PzIxQyIWIsTbPHIisq+LTRCOt+rp7dIyugbvbwuSo/cZL8dyJFY11MYP1ozI/a3x51Q== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a05:6a00:21c8:b0:4fd:f89f:ec0e with SMTP id t8-20020a056a0021c800b004fdf89fec0emr6710829pfj.83.1650661574708; Fri, 22 Apr 2022 14:06:14 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:42 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-17-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 16/20] KVM: x86/mmu: Extend make_huge_page_split_spte() for the shadow MMU From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently make_huge_page_split_spte() assumes execute permissions can be granted to any 4K SPTE when splitting huge pages. This is true for the TDP MMU but is not necessarily true for the shadow MMU, since KVM may be shadowing a non-executable huge page. To fix this, pass in the child shadow page where the huge page will be split and derive the execution permission from the shadow page's role. This is correct because huge pages are always split with direct shadow page and thus the shadow page role contains the correct access permissions. No functional change intended. Signed-off-by: David Matlack --- arch/x86/kvm/mmu/spte.c | 13 +++++++------ arch/x86/kvm/mmu/spte.h | 2 +- arch/x86/kvm/mmu/tdp_mmu.c | 2 +- 3 files changed, 9 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 4739b53c9734..9db98fbeee61 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -215,10 +215,11 @@ static u64 make_spte_executable(u64 spte) * This is used during huge page splitting to build the SPTEs that make up the * new page table. */ -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) +u64 make_huge_page_split_spte(u64 huge_spte, struct kvm_mmu_page *sp, int index) { + bool exec_allowed = sp->role.access & ACC_EXEC_MASK; + int child_level = sp->role.level; u64 child_spte; - int child_level; if (WARN_ON_ONCE(!is_shadow_present_pte(huge_spte))) return 0; @@ -227,7 +228,6 @@ u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) return 0; child_spte = huge_spte; - child_level = huge_level - 1; /* * The child_spte already has the base address of the huge page being @@ -240,10 +240,11 @@ u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) child_spte &= ~PT_PAGE_SIZE_MASK; /* - * When splitting to a 4K page, mark the page executable as the - * NX hugepage mitigation no longer applies. + * When splitting to a 4K page where execution is allowed, mark + * the page executable as the NX hugepage mitigation no longer + * applies. */ - if (is_nx_huge_page_enabled()) + if (exec_allowed && is_nx_huge_page_enabled()) child_spte = make_spte_executable(child_spte); } diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h index 73f12615416f..921ea77f1b5e 100644 --- a/arch/x86/kvm/mmu/spte.h +++ b/arch/x86/kvm/mmu/spte.h @@ -415,7 +415,7 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, unsigned int pte_access, gfn_t gfn, kvm_pfn_t pfn, u64 old_spte, bool prefetch, bool can_unsync, bool host_writable, u64 *new_spte); -u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index); +u64 make_huge_page_split_spte(u64 huge_spte, struct kvm_mmu_page *sp, int index); u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled); u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access); u64 mark_spte_for_access_track(u64 spte); diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 566548a3efa7..110a34ca41c2 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1469,7 +1469,7 @@ static int tdp_mmu_split_huge_page(struct kvm *kvm, struct tdp_iter *iter, * not been linked in yet and thus is not reachable from any other CPU. */ for (i = 0; i < PT64_ENT_PER_PAGE; i++) - sp->spt[i] = make_huge_page_split_spte(huge_spte, level, i); + sp->spt[i] = make_huge_page_split_spte(huge_spte, sp, i); /* * Replace the huge spte with a pointer to the populated lower level From patchwork Fri Apr 22 21:05:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824158 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CDBFC433F5 for ; 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Fri, 22 Apr 2022 14:06:16 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:43 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-18-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 17/20] KVM: x86/mmu: Zap collapsible SPTEs at all levels in the shadow MMU From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently KVM only zaps collapsible 4KiB SPTEs in the shadow MMU (i.e. in the rmap). This is fine for now KVM never creates intermediate huge pages during dirty logging, i.e. a 1GiB page is never partially split to a 2MiB page. However, this will stop being true once the shadow MMU participates in eager page splitting, which can in fact leave behind partially split huge pages. In preparation for that change, change the shadow MMU to iterate over all necessary levels when zapping collapsible SPTEs. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index ed65899d15a2..479c581e8a96 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6098,18 +6098,25 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, return need_tlb_flush; } +static void kvm_rmap_zap_collapsible_sptes(struct kvm *kvm, + const struct kvm_memory_slot *slot) +{ + /* + * Note, use KVM_MAX_HUGEPAGE_LEVEL - 1 since there's no need to zap + * pages that are already mapped at the maximum possible level. + */ + if (slot_handle_level(kvm, slot, kvm_mmu_zap_collapsible_spte, + PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL - 1, + true)) + kvm_arch_flush_remote_tlbs_memslot(kvm, slot); +} + void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, const struct kvm_memory_slot *slot) { if (kvm_memslots_have_rmaps(kvm)) { write_lock(&kvm->mmu_lock); - /* - * Zap only 4k SPTEs since the legacy MMU only supports dirty - * logging at a 4k granularity and never creates collapsible - * 2m SPTEs during dirty logging. - */ - if (slot_handle_level_4k(kvm, slot, kvm_mmu_zap_collapsible_spte, true)) - kvm_arch_flush_remote_tlbs_memslot(kvm, slot); + kvm_rmap_zap_collapsible_sptes(kvm, slot); write_unlock(&kvm->mmu_lock); } From patchwork Fri Apr 22 21:05:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824161 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 364EBC433EF for ; Fri, 22 Apr 2022 22:13:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232515AbiDVWQg (ORCPT ); Fri, 22 Apr 2022 18:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232513AbiDVWPj (ORCPT ); Fri, 22 Apr 2022 18:15:39 -0400 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BC6423E82B for ; 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Fri, 22 Apr 2022 14:06:17 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:44 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-19-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 18/20] KVM: x86/mmu: Refactor drop_large_spte() From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org drop_large_spte() drops a large SPTE if it exists and then flushes TLBs. Its helper function, __drop_large_spte(), does the drop without the flush. In preparation for eager page splitting, which will need to sometimes flush when dropping large SPTEs (and sometimes not), push the flushing logic down into __drop_large_spte() and add a bool parameter to control it. No functional change intended. Reviewed-by: Peter Xu Signed-off-by: David Matlack --- arch/x86/kvm/mmu/mmu.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 479c581e8a96..a5961c17eb36 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1183,28 +1183,29 @@ static void drop_spte(struct kvm *kvm, u64 *sptep) rmap_remove(kvm, sptep); } - -static bool __drop_large_spte(struct kvm *kvm, u64 *sptep) +static void __drop_large_spte(struct kvm *kvm, u64 *sptep, bool flush) { - if (is_large_pte(*sptep)) { - WARN_ON(sptep_to_sp(sptep)->role.level == PG_LEVEL_4K); - drop_spte(kvm, sptep); - return true; - } + struct kvm_mmu_page *sp; - return false; -} + if (!is_large_pte(*sptep)) + return; -static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) -{ - if (__drop_large_spte(vcpu->kvm, sptep)) { - struct kvm_mmu_page *sp = sptep_to_sp(sptep); + sp = sptep_to_sp(sptep); + WARN_ON(sp->role.level == PG_LEVEL_4K); - kvm_flush_remote_tlbs_with_address(vcpu->kvm, sp->gfn, + drop_spte(kvm, sptep); + + if (flush) { + kvm_flush_remote_tlbs_with_address(kvm, sp->gfn, KVM_PAGES_PER_HPAGE(sp->role.level)); } } +static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) +{ + return __drop_large_spte(vcpu->kvm, sptep, true); +} + /* * Write-protect on the specified @sptep, @pt_protect indicates whether * spte write-protection is caused by protecting shadow page table. From patchwork Fri Apr 22 21:05:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824160 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BC43C433EF for ; Fri, 22 Apr 2022 22:13:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232235AbiDVWQe (ORCPT ); Fri, 22 Apr 2022 18:16:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60448 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232528AbiDVWPk (ORCPT ); Fri, 22 Apr 2022 18:15:40 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD05931AA8D for ; Fri, 22 Apr 2022 14:06:19 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id i69-20020a636d48000000b003aa4ae583bcso5644197pgc.14 for ; Fri, 22 Apr 2022 14:06:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=AokhUPI0w8x0YtojIWxDMCet7uQDG5b+eiidLmmEvGw=; b=LhtF+x5GT2s+QDOONs7fKAv3klJirfq1E+v9o0whKKGLAbQq1FM3tOZBTdaIvvK7+L TzIQqqo1+sUXr7JMRYt48OzS5nc57m+foZQJ4+tWk6n0ghhE5vbbzvlQtshHIvnC6B21 71FG+NJEuVyObMrdlcGXMpNRdY52UEqJNJKVcJNqrxmYDakOYXjMZLONxo6IXQ8BaYQQ S26vPuFCFSNjvTbFxh3fzJt6BM1vtEwSchoRN/WM4JlWMUurXqyT7unrHIaMm9oosAu8 jNtTkaR9TqwkcD7OwIDvUeWGCHL8ZB+QAZ5mdwzIArWYtR/XPKgG2NBnEry2tlN/sx4K ZpeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=AokhUPI0w8x0YtojIWxDMCet7uQDG5b+eiidLmmEvGw=; b=P4ra260NzU2UCt16fnwvKOInmvblRTJEUabso7WR74DIEnfHtA3hrBQeHgHmke3lUr L8tlV7tEofVMudXCO3rOBWZsW9rt2Egk2vCBjtSAHvbgBOhr2ACdhRgA+uWnYGmoYTCI EQNSKu/pWtDj72OrD3jUvwsc1hB67+Cqcb0VzOigrivT25XRwPMUMgt4xO/8rR+OaAFS ErLDuTFG/YIcSYbnJh1EkJCLv+fKutMKLAxpv1Gzle3r0dMhs8eztLJMv09DGwd6aUt3 rSFQRqT81C85J6+TzLX2LVqsYRd4HAOswnKE+GtFF2+fHaqY8P6fzZpU+os5UaZuedbe rc5g== X-Gm-Message-State: AOAM532MO3Bu6ixvMYUdD79a4aAEsvIuieZx2qC0zxPtRB138irfjfGP p8MKrohdRRcv7TrMFM7FjwgW5TV7sw0jsA== X-Google-Smtp-Source: ABdhPJxHVFmIWyEEslp8lfnPYbT/7EtrSdKmonQmeUAkEv1kyEMdkBMNSlhDn9mjvTBGmUngHH899Dm8lUOMxA== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a17:902:edc5:b0:156:68e4:416 with SMTP id q5-20020a170902edc500b0015668e40416mr6461850plk.87.1650661579256; Fri, 22 Apr 2022 14:06:19 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:45 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-20-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 19/20] KVM: Allow for different capacities in kvm_mmu_memory_cache structs From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at declaration time rather than being fixed for all declarations. This will be used in a follow-up commit to declare an cache in x86 with a capacity of 512+ objects without having to increase the capacity of all caches in KVM. This change requires each cache now specify its capacity at runtime, since the cache struct itself no longer has a fixed capacity known at compile time. To protect against someone accidentally defining a kvm_mmu_memory_cache struct directly (without the extra storage), this commit includes a WARN_ON() in kvm_mmu_topup_memory_cache(). In order to support different capacities, this commit changes the objects pointer array to be dynamically allocated the first time the cache is topped-up. An alternative would be to lay out the objects array after the kvm_mmu_memory_cache struct, which can be done at compile time. But that change, unfortunately, adds some grottiness to arm64 and riscv, which uses a function-local (i.e. stack-allocated) kvm_mmu_memory_cache struct. Since C does not allow anonymous structs in functions, the new wrapper struct that contains kvm_mmu_memory_cache and the objects pointer array, must be named, which means dealing with an outer and inner struct. The outer struct can't be dropped since then there would be no guarantee the kvm_mmu_memory_cache struct and objects array would be laid out consecutively on the stack. No functional change intended. Signed-off-by: David Matlack --- arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/mmu.c | 5 ++++- arch/mips/kvm/mips.c | 2 ++ arch/riscv/kvm/mmu.c | 14 +++++++------- arch/riscv/kvm/vcpu.c | 1 + arch/x86/kvm/mmu/mmu.c | 9 +++++++++ include/linux/kvm_types.h | 9 +++++++-- virt/kvm/kvm_main.c | 20 ++++++++++++++++++-- 8 files changed, 49 insertions(+), 12 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 523bc934fe2f..66f6706a1037 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -320,6 +320,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) vcpu->arch.target = -1; bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; /* Set up the timer */ diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 53ae2c0640bc..2f2ef6b60ff4 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -764,7 +764,10 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, { phys_addr_t addr; int ret = 0; - struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, NULL, }; + struct kvm_mmu_memory_cache cache = { + .capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, + .gfp_zero = __GFP_ZERO, + }; struct kvm_pgtable *pgt = kvm->arch.mmu.pgt; enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_R | diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index a25e0b73ee70..45c7179144dc 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -387,6 +387,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (err) goto out_free_gebase; + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + return 0; out_free_gebase: diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index f80a34fbf102..0e042f40d737 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -347,10 +347,10 @@ static int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa, int ret = 0; unsigned long pfn; phys_addr_t addr, end; - struct kvm_mmu_memory_cache pcache; - - memset(&pcache, 0, sizeof(pcache)); - pcache.gfp_zero = __GFP_ZERO; + struct kvm_mmu_memory_cache cache = { + .capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, + .gfp_zero = __GFP_ZERO, + }; end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK; pfn = __phys_to_pfn(hpa); @@ -361,12 +361,12 @@ static int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa, if (!writable) pte = pte_wrprotect(pte); - ret = kvm_mmu_topup_memory_cache(&pcache, stage2_pgd_levels); + ret = kvm_mmu_topup_memory_cache(&cache.cache, stage2_pgd_levels); if (ret) goto out; spin_lock(&kvm->mmu_lock); - ret = stage2_set_pte(kvm, 0, &pcache, addr, &pte); + ret = stage2_set_pte(kvm, 0, &cache.cache, addr, &pte); spin_unlock(&kvm->mmu_lock); if (ret) goto out; @@ -375,7 +375,7 @@ static int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa, } out: - kvm_mmu_free_memory_cache(&pcache); + kvm_mmu_free_memory_cache(&cache.cache); return ret; } diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 6785aef4cbd4..bbcb9d4a04fb 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -94,6 +94,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) /* Mark this VCPU never ran */ vcpu->arch.ran_atleast_once = false; + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; /* Setup ISA features available to VCPU */ diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index a5961c17eb36..5b1458b911ab 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5719,12 +5719,21 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) { int ret; + vcpu->arch.mmu_pte_list_desc_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache; vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_page_header_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_shadowed_info_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + + vcpu->arch.mmu_shadow_page_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; vcpu->arch.mmu = &vcpu->arch.root_mmu; diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h index ac1ebb37a0ff..549103a4f7bc 100644 --- a/include/linux/kvm_types.h +++ b/include/linux/kvm_types.h @@ -83,14 +83,19 @@ struct gfn_to_pfn_cache { * MMU flows is problematic, as is triggering reclaim, I/O, etc... while * holding MMU locks. Note, these caches act more like prefetch buffers than * classical caches, i.e. objects are not returned to the cache on being freed. + * + * The storage for the cache object pointers is allocated dynamically when the + * cache is topped-up. The capacity field defines the number of object pointers + * available after the struct. */ struct kvm_mmu_memory_cache { int nobjs; + int capacity; gfp_t gfp_zero; struct kmem_cache *kmem_cache; - void *objects[KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE]; + void **objects; }; -#endif +#endif /* KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE */ #define HALT_POLL_HIST_COUNT 32 diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index dfb7dabdbc63..29f84d7c1950 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -371,12 +371,23 @@ static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc, int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min) { + gfp_t gfp = GFP_KERNEL_ACCOUNT; void *obj; if (mc->nobjs >= min) return 0; - while (mc->nobjs < ARRAY_SIZE(mc->objects)) { - obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT); + + if (WARN_ON(mc->capacity == 0)) + return -EINVAL; + + if (!mc->objects) { + mc->objects = kvmalloc_array(sizeof(void *), mc->capacity, gfp); + if (!mc->objects) + return -ENOMEM; + } + + while (mc->nobjs < mc->capacity) { + obj = mmu_memory_cache_alloc_obj(mc, gfp); if (!obj) return mc->nobjs >= min ? 0 : -ENOMEM; mc->objects[mc->nobjs++] = obj; @@ -397,6 +408,11 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) else free_page((unsigned long)mc->objects[--mc->nobjs]); } + + kvfree(mc->objects); + + /* Note, must set to NULL to avoid use-after-free in the next top-up. */ + mc->objects = NULL; } void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc) From patchwork Fri Apr 22 21:05:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12824159 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D3D0C433F5 for ; Fri, 22 Apr 2022 22:13:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232252AbiDVWQb (ORCPT ); Fri, 22 Apr 2022 18:16:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232524AbiDVWPk (ORCPT ); Fri, 22 Apr 2022 18:15:40 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A10831AA9E for ; Fri, 22 Apr 2022 14:06:21 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id i69-20020a636d48000000b003aa4ae583bcso5644231pgc.14 for ; Fri, 22 Apr 2022 14:06:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=qNafRzYSxajZcD5Mb7G7HwgtsT9tx7k/FBBt0jG1f+0=; b=gqbc3uOkLP/e9O9i10UZ3Vk6hwl/aQe7I/s77XD9XyL5XYVrzQEYV68Jqod5bYUl0L q+gYahYOIn96sXYYvjTMU6t0BOKzzqzxqIAFtYvgvNp7hXLvm5bnUdYj2s5JHWBlOscQ 1ADwC5GBoF/14EzT8KKh2MM+5Tw4r62oSr2X01YxxojTIZHjBdhX8TEUkma8jZz6IuMo /dGG0Tt7HnkGmT7Ank1K/tMzZf7Qi1NNGnpI8AQVwnZIfzsI6+vzKYwE2UloSVq9rKEc 0Q118WO3rFhjgKjuTsi8UN7N52XVuAmJGT7JGAoD0S9vO57doQnadpECPZsXRLlaniAv hP7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=qNafRzYSxajZcD5Mb7G7HwgtsT9tx7k/FBBt0jG1f+0=; b=XQTYw4ayTVy8ulDlhZOXdykMXFWdQIjJrlipzvYE6cAvRGhriftlIXpXuGqwBd0IJH UiadXrvCwd+N3ahraW9iqcTtJjQVgUJ2kkvKaq2QHMNMS7LR1DkeiQENV5N+NsV1aUko uKOrxLG+jZCZnkuiuNo9XYZVQHECirmytNxeasXDC6KVqsuVZw1vk9pSMPE4DW1Q6Ync 1Eb7N6jr1WvujqgR7mp30SjVN4M3lue09vQ4sjDe4w5/S6alaGL1/mNHQyViZBNu48HA os7HV5B9+doxGO9ipP8UsDRyimOpPUtCTtWa/yDjrXhzAsonXSfVhsyfLeGNrAO8tUea I7Vw== X-Gm-Message-State: AOAM530tf1ApTM4+0d5PWw09HD8cBe3cGLSz/wvB70WgJRRU2Y8zmcEn 9QMFWeLvPg9Yp/VbhDONDzIf1p2sWsHrVw== X-Google-Smtp-Source: ABdhPJwrUfgV11nRSDBwHOtcD13yNpJbzIJyIWwUuk5MB+4+IpX0/DyBgGZEFv0WSXiPMJ+gf/ImPMjruaCU5Q== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a05:6a00:16c7:b0:4f7:e497:69c7 with SMTP id l7-20020a056a0016c700b004f7e49769c7mr6793716pfc.7.1650661580864; Fri, 22 Apr 2022 14:06:20 -0700 (PDT) Date: Fri, 22 Apr 2022 21:05:46 +0000 In-Reply-To: <20220422210546.458943-1-dmatlack@google.com> Message-Id: <20220422210546.458943-21-dmatlack@google.com> Mime-Version: 1.0 References: <20220422210546.458943-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.rc2.479.g8af0fa9b8e-goog Subject: [PATCH v4 20/20] KVM: x86/mmu: Extend Eager Page Splitting to nested MMUs From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add support for Eager Page Splitting pages that are mapped by nested MMUs. Walk through the rmap first splitting all 1GiB pages to 2MiB pages, and then splitting all 2MiB pages to 4KiB pages. Note, Eager Page Splitting is limited to nested MMUs as a policy rather than due to any technical reason (the sp->role.guest_mode check could just be deleted and Eager Page Splitting would work correctly for all shadow MMU pages). There is really no reason to support Eager Page Splitting for tdp_mmu=N, since such support will eventually be phased out, and there is no current use case supporting Eager Page Splitting on hosts where TDP is either disabled or unavailable in hardware. Furthermore, future improvements to nested MMU scalability may diverge the code from the legacy shadow paging implementation. These improvements will be simpler to make if Eager Page Splitting does not have to worry about legacy shadow paging. Splitting huge pages mapped by nested MMUs requires dealing with some extra complexity beyond that of the TDP MMU: (1) The shadow MMU has a limit on the number of shadow pages that are allowed to be allocated. So, as a policy, Eager Page Splitting refuses to split if there are KVM_MIN_FREE_MMU_PAGES or fewer pages available. (2) Splitting a huge page may end up re-using an existing lower level shadow page tables. This is unlike the TDP MMU which always allocates new shadow page tables when splitting. (3) When installing the lower level SPTEs, they must be added to the rmap which may require allocating additional pte_list_desc structs. Case (2) is especially interesting since it may require a TLB flush, unlike the TDP MMU which can fully split huge pages without any TLB flushes. Specifically, an existing lower level page table may point to even lower level page tables that are not fully populated, effectively unmapping a portion of the huge page, which requires a flush. This commit performs such flushes after dropping the huge page and before installing the lower level page table. This TLB flush could instead be delayed until the MMU lock is about to be dropped, which would batch flushes for multiple splits. However these flushes should be rare in practice (a huge page must be aliased in multiple SPTEs and have been split for NX Huge Pages in only some of them). Flushing immediately is simpler to plumb and also reduces the chances of tripping over a CPU bug (e.g. see iTLB multihit). Suggested-by: Peter Feiner [ This commit is based off of the original implementation of Eager Page Splitting from Peter in Google's kernel from 2016. ] Signed-off-by: David Matlack --- .../admin-guide/kernel-parameters.txt | 3 +- arch/x86/include/asm/kvm_host.h | 20 ++ arch/x86/kvm/mmu/mmu.c | 276 +++++++++++++++++- arch/x86/kvm/x86.c | 6 + 4 files changed, 296 insertions(+), 9 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3f1cc5e317ed..bc3ad3d4df0b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2387,8 +2387,7 @@ the KVM_CLEAR_DIRTY ioctl, and only for the pages being cleared. - Eager page splitting currently only supports splitting - huge pages mapped by the TDP MMU. + Eager page splitting is only supported when kvm.tdp_mmu=Y. Default is Y (on). diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 15131aa05701..5df4dff385a1 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1240,6 +1240,24 @@ struct kvm_arch { hpa_t hv_root_tdp; spinlock_t hv_root_tdp_lock; #endif + + /* + * Memory caches used to allocate shadow pages when performing eager + * page splitting. No need for a shadowed_info_cache since eager page + * splitting only allocates direct shadow pages. + */ + struct kvm_mmu_memory_cache split_shadow_page_cache; + struct kvm_mmu_memory_cache split_page_header_cache; + + /* + * Memory cache used to allocate pte_list_desc structs while splitting + * huge pages. In the worst case, to split one huge page, 512 + * pte_list_desc structs are needed to add each lower level leaf sptep + * to the rmap plus 1 to extend the parent_ptes rmap of the lower level + * page table. + */ +#define SPLIT_DESC_CACHE_CAPACITY 513 + struct kvm_mmu_memory_cache split_desc_cache; }; struct kvm_vm_stat { @@ -1608,6 +1626,8 @@ void kvm_mmu_zap_all(struct kvm *kvm); void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen); void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages); +void free_split_caches(struct kvm *kvm); + int load_pdptrs(struct kvm_vcpu *vcpu, unsigned long cr3); int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa, diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 5b1458b911ab..9a59ec9b78fb 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5897,6 +5897,18 @@ int kvm_mmu_init_vm(struct kvm *kvm) node->track_write = kvm_mmu_pte_write; node->track_flush_slot = kvm_mmu_invalidate_zap_pages_in_memslot; kvm_page_track_register_notifier(kvm, node); + + kvm->arch.split_page_header_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + kvm->arch.split_page_header_cache.kmem_cache = mmu_page_header_cache; + kvm->arch.split_page_header_cache.gfp_zero = __GFP_ZERO; + + kvm->arch.split_shadow_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + kvm->arch.split_shadow_page_cache.gfp_zero = __GFP_ZERO; + + kvm->arch.split_desc_cache.capacity = SPLIT_DESC_CACHE_CAPACITY; + kvm->arch.split_desc_cache.kmem_cache = pte_list_desc_cache; + kvm->arch.split_desc_cache.gfp_zero = __GFP_ZERO; + return 0; } @@ -6028,15 +6040,256 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, kvm_arch_flush_remote_tlbs_memslot(kvm, memslot); } +void free_split_caches(struct kvm *kvm) +{ + kvm_mmu_free_memory_cache(&kvm->arch.split_desc_cache); + kvm_mmu_free_memory_cache(&kvm->arch.split_page_header_cache); + kvm_mmu_free_memory_cache(&kvm->arch.split_shadow_page_cache); +} + +static inline bool need_topup(struct kvm_mmu_memory_cache *cache, int min) +{ + return kvm_mmu_memory_cache_nr_free_objects(cache) < min; +} + +static bool need_topup_split_caches_or_resched(struct kvm *kvm) +{ + if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) + return true; + + /* + * In the worst case, SPLIT_DESC_CACHE_CAPACITY descriptors are needed + * to split a single huge page. Calculating how many are actually needed + * is possible but not worth the complexity. + */ + return need_topup(&kvm->arch.split_desc_cache, SPLIT_DESC_CACHE_CAPACITY) || + need_topup(&kvm->arch.split_page_header_cache, 1) || + need_topup(&kvm->arch.split_shadow_page_cache, 1); +} + +static int topup_split_caches(struct kvm *kvm) +{ + int r; + + r = kvm_mmu_topup_memory_cache(&kvm->arch.split_desc_cache, + SPLIT_DESC_CACHE_CAPACITY); + if (r) + return r; + + r = kvm_mmu_topup_memory_cache(&kvm->arch.split_page_header_cache, 1); + if (r) + return r; + + return kvm_mmu_topup_memory_cache(&kvm->arch.split_shadow_page_cache, 1); +} + +static struct kvm_mmu_page *nested_mmu_get_sp_for_split(struct kvm *kvm, u64 *huge_sptep) +{ + struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep); + struct shadow_page_caches caches = {}; + union kvm_mmu_page_role role; + unsigned int access; + gfn_t gfn; + + gfn = kvm_mmu_page_get_gfn(huge_sp, huge_sptep - huge_sp->spt); + access = kvm_mmu_page_get_access(huge_sp, huge_sptep - huge_sp->spt); + + /* + * Note, huge page splitting always uses direct shadow pages, regardless + * of whether the huge page itself is mapped by a direct or indirect + * shadow page, since the huge page region itself is being directly + * mapped with smaller pages. + */ + role = kvm_mmu_child_role(huge_sptep, /*direct=*/true, access); + + /* Direct SPs do not require a shadowed_info_cache. */ + caches.page_header_cache = &kvm->arch.split_page_header_cache; + caches.shadow_page_cache = &kvm->arch.split_shadow_page_cache; + + /* Safe to pass NULL for vCPU since requesting a direct SP. */ + return __kvm_mmu_get_shadow_page(kvm, NULL, &caches, gfn, role); +} + +static void nested_mmu_split_huge_page(struct kvm *kvm, + const struct kvm_memory_slot *slot, + u64 *huge_sptep) + +{ + struct kvm_mmu_memory_cache *cache = &kvm->arch.split_desc_cache; + u64 huge_spte = READ_ONCE(*huge_sptep); + struct kvm_mmu_page *sp; + bool flush = false; + u64 *sptep, spte; + gfn_t gfn; + int index; + + sp = nested_mmu_get_sp_for_split(kvm, huge_sptep); + + for (index = 0; index < PT64_ENT_PER_PAGE; index++) { + sptep = &sp->spt[index]; + gfn = kvm_mmu_page_get_gfn(sp, index); + + /* + * The SP may already have populated SPTEs, e.g. if this huge + * page is aliased by multiple sptes with the same access + * permissions. These entries are guaranteed to map the same + * gfn-to-pfn translation since the SP is direct, so no need to + * modify them. + * + * However, if a given SPTE points to a lower level page table, + * that lower level page table may only be partially populated. + * Installing such SPTEs would effectively unmap a potion of the + * huge page, which requires a TLB flush. + */ + if (is_shadow_present_pte(*sptep)) { + flush |= !is_last_spte(*sptep, sp->role.level); + continue; + } + + spte = make_huge_page_split_spte(huge_spte, sp, index); + mmu_spte_set(sptep, spte); + __rmap_add(kvm, cache, slot, sptep, gfn, sp->role.access); + } + + /* + * Replace the huge spte with a pointer to the populated lower level + * page table. If the lower-level page table indentically maps the huge + * page (i.e. no memory is unmapped), there's no need for a TLB flush. + * Otherwise, flush TLBs after dropping the huge page and before + * installing the shadow page table. + */ + __drop_large_spte(kvm, huge_sptep, flush); + __link_shadow_page(cache, huge_sptep, sp); +} + +static int nested_mmu_try_split_huge_page(struct kvm *kvm, + const struct kvm_memory_slot *slot, + u64 *huge_sptep) +{ + struct kvm_mmu_page *huge_sp = sptep_to_sp(huge_sptep); + int level, r = 0; + gfn_t gfn; + u64 spte; + + /* Grab information for the tracepoint before dropping the MMU lock. */ + gfn = kvm_mmu_page_get_gfn(huge_sp, huge_sptep - huge_sp->spt); + level = huge_sp->role.level; + spte = *huge_sptep; + + if (kvm_mmu_available_pages(kvm) <= KVM_MIN_FREE_MMU_PAGES) { + r = -ENOSPC; + goto out; + } + + if (need_topup_split_caches_or_resched(kvm)) { + write_unlock(&kvm->mmu_lock); + cond_resched(); + /* + * If the topup succeeds, return -EAGAIN to indicate that the + * rmap iterator should be restarted because the MMU lock was + * dropped. + */ + r = topup_split_caches(kvm) ?: -EAGAIN; + write_lock(&kvm->mmu_lock); + goto out; + } + + nested_mmu_split_huge_page(kvm, slot, huge_sptep); + +out: + trace_kvm_mmu_split_huge_page(gfn, spte, level, r); + return r; +} + +static bool nested_mmu_skip_split_huge_page(u64 *huge_sptep) +{ + struct kvm_mmu_page *sp = sptep_to_sp(huge_sptep); + + /* TDP MMU is enabled, so rmap should only contain nested MMU SPs. */ + if (WARN_ON_ONCE(!sp->role.guest_mode)) + return true; + + /* The rmaps should never contain non-leaf SPTEs. */ + if (WARN_ON_ONCE(!is_large_pte(*huge_sptep))) + return true; + + /* SPs with level >PG_LEVEL_4K should never by unsync. */ + if (WARN_ON_ONCE(sp->unsync)) + return true; + + /* Don't bother splitting huge pages on invalid SPs. */ + if (sp->role.invalid) + return true; + + return false; +} + +static bool nested_mmu_try_split_huge_pages(struct kvm *kvm, + struct kvm_rmap_head *rmap_head, + const struct kvm_memory_slot *slot) +{ + struct rmap_iterator iter; + u64 *huge_sptep; + int r; + +restart: + for_each_rmap_spte(rmap_head, &iter, huge_sptep) { + if (nested_mmu_skip_split_huge_page(huge_sptep)) + continue; + + r = nested_mmu_try_split_huge_page(kvm, slot, huge_sptep); + + /* + * The split succeeded or needs to be retried because the MMU + * lock was dropped. Either way, restart the iterator to get it + * back into a consistent state. + */ + if (!r || r == -EAGAIN) + goto restart; + + /* The split failed and shouldn't be retried (e.g. -ENOMEM). */ + break; + } + + return false; +} + +static void kvm_nested_mmu_try_split_huge_pages(struct kvm *kvm, + const struct kvm_memory_slot *slot, + gfn_t start, gfn_t end, + int target_level) +{ + int level; + + /* + * Split huge pages starting with KVM_MAX_HUGEPAGE_LEVEL and working + * down to the target level. This ensures pages are recursively split + * all the way to the target level. There's no need to split pages + * already at the target level. + */ + for (level = KVM_MAX_HUGEPAGE_LEVEL; level > target_level; level--) { + slot_handle_level_range(kvm, slot, + nested_mmu_try_split_huge_pages, + level, level, start, end - 1, + true, false); + } +} + /* Must be called with the mmu_lock held in write-mode. */ void kvm_mmu_try_split_huge_pages(struct kvm *kvm, const struct kvm_memory_slot *memslot, u64 start, u64 end, int target_level) { - if (is_tdp_mmu_enabled(kvm)) - kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, - target_level, false); + if (!is_tdp_mmu_enabled(kvm)) + return; + + kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, + false); + + if (kvm_memslots_have_rmaps(kvm)) + kvm_nested_mmu_try_split_huge_pages(kvm, memslot, start, end, + target_level); /* * A TLB flush is unnecessary at this point for the same resons as in @@ -6051,10 +6304,19 @@ void kvm_mmu_slot_try_split_huge_pages(struct kvm *kvm, u64 start = memslot->base_gfn; u64 end = start + memslot->npages; - if (is_tdp_mmu_enabled(kvm)) { - read_lock(&kvm->mmu_lock); - kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, true); - read_unlock(&kvm->mmu_lock); + if (!is_tdp_mmu_enabled(kvm)) + return; + + read_lock(&kvm->mmu_lock); + kvm_tdp_mmu_try_split_huge_pages(kvm, memslot, start, end, target_level, + true); + read_unlock(&kvm->mmu_lock); + + if (kvm_memslots_have_rmaps(kvm)) { + write_lock(&kvm->mmu_lock); + kvm_nested_mmu_try_split_huge_pages(kvm, memslot, start, end, + target_level); + write_unlock(&kvm->mmu_lock); } /* diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ab336f7c82e4..e123e24a130f 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12161,6 +12161,12 @@ static void kvm_mmu_slot_apply_flags(struct kvm *kvm, * page faults will create the large-page sptes. */ kvm_mmu_zap_collapsible_sptes(kvm, new); + + /* + * Free any memory left behind by eager page splitting. Ignore + * the module parameter since userspace might have changed it. + */ + free_split_caches(kvm); } else { /* * Initially-all-set does not require write protecting any page,