From patchwork Wed Sep 14 08:34:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 12975783 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 92BECECAAD8 for ; Wed, 14 Sep 2022 08:35:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230166AbiINIfe (ORCPT ); Wed, 14 Sep 2022 04:35:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35726 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230103AbiINIf3 (ORCPT ); Wed, 14 Sep 2022 04:35:29 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 260A74DB2D for ; Wed, 14 Sep 2022 01:35:27 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E21F9B811C5 for ; Wed, 14 Sep 2022 08:35:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3823C433D7; Wed, 14 Sep 2022 08:35:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1663144523; bh=HUAUuVq8YZYixepTCXAqJPT1+9QpujQsJvquSsGKD5Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iieEsEtZoslbJcY7qhXOST1Vb0lbSnTeeOm4vPwImd3pxJUa68bb+5nerspCUhf6F nufftViAXYX6ZqN51ParPIP77TFMZz9dxIMw+q1PitD1CwquV5TiqvphN4ZglYdrjA TaonDeM5sG4+H+J50c4bQkUQCOEORoKWzFDzuZtyJv4Q8r5ztMd8JPiU+8Tp2BMvx6 njLVVFdPNOOVIOH1ZKSHYqqadIJzszJj5SKYTrGCYY48Kwa2LcJ+1t72qzPcrlxeUG KP+GjaocjMowAQAvjYFGgaYknN4/3b0ivPZGd9tayHx7ACpOZ04tmGQWV4z1R/bvQk SNt64oW4zbASw== From: Will Deacon To: kvmarm@lists.cs.columbia.edu Cc: Will Deacon , Sean Christopherson , Vincent Donnefort , Alexandru Elisei , Catalin Marinas , James Morse , Chao Peng , Quentin Perret , Suzuki K Poulose , Mark Rutland , Fuad Tabba , Oliver Upton , Marc Zyngier , kernel-team@android.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 04/25] KVM: arm64: Fix-up hyp stage-1 refcounts for all pages mapped at EL2 Date: Wed, 14 Sep 2022 09:34:39 +0100 Message-Id: <20220914083500.5118-5-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220914083500.5118-1-will@kernel.org> References: <20220914083500.5118-1-will@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Quentin Perret In order to allow unmapping arbitrary memory pages from the hypervisor stage-1 page-table, fix-up the initial refcount for pages that have been mapped before the 'vmemmap' array was up and running so that it accurately accounts for all existing hypervisor mappings. This is achieved by traversing the entire hypervisor stage-1 page-table during initialisation of EL2 and updating the corresponding 'struct hyp_page' for each valid mapping. Signed-off-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/kvm/hyp/nvhe/setup.c | 62 +++++++++++++++++++++++---------- 1 file changed, 43 insertions(+), 19 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 579eb4f73476..8f2726d7e201 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -185,12 +185,11 @@ static void hpool_put_page(void *addr) hyp_put_page(&hpool, addr); } -static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, - kvm_pte_t *ptep, - enum kvm_pgtable_walk_flags flag, - void * const arg) +static int fix_host_ownership_walker(u64 addr, u64 end, u32 level, + kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, + void * const arg) { - struct kvm_pgtable_mm_ops *mm_ops = arg; enum kvm_pgtable_prot prot; enum pkvm_page_state state; kvm_pte_t pte = *ptep; @@ -199,15 +198,6 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, if (!kvm_pte_valid(pte)) return 0; - /* - * Fix-up the refcount for the page-table pages as the early allocator - * was unable to access the hyp_vmemmap and so the buddy allocator has - * initialised the refcount to '1'. - */ - mm_ops->get_page(ptep); - if (flag != KVM_PGTABLE_WALK_LEAF) - return 0; - if (level != (KVM_PGTABLE_MAX_LEVELS - 1)) return -EINVAL; @@ -236,12 +226,30 @@ static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, return host_stage2_idmap_locked(phys, PAGE_SIZE, prot); } -static int finalize_host_mappings(void) +static int fix_hyp_pgtable_refcnt_walker(u64 addr, u64 end, u32 level, + kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, + void * const arg) +{ + struct kvm_pgtable_mm_ops *mm_ops = arg; + kvm_pte_t pte = *ptep; + + /* + * Fix-up the refcount for the page-table pages as the early allocator + * was unable to access the hyp_vmemmap and so the buddy allocator has + * initialised the refcount to '1'. + */ + if (kvm_pte_valid(pte)) + mm_ops->get_page(ptep); + + return 0; +} + +static int fix_host_ownership(void) { struct kvm_pgtable_walker walker = { - .cb = finalize_host_mappings_walker, - .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, - .arg = pkvm_pgtable.mm_ops, + .cb = fix_host_ownership_walker, + .flags = KVM_PGTABLE_WALK_LEAF, }; int i, ret; @@ -257,6 +265,18 @@ static int finalize_host_mappings(void) return 0; } +static int fix_hyp_pgtable_refcnt(void) +{ + struct kvm_pgtable_walker walker = { + .cb = fix_hyp_pgtable_refcnt_walker, + .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, + .arg = pkvm_pgtable.mm_ops, + }; + + return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits), + &walker); +} + void __noreturn __pkvm_init_finalise(void) { struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data); @@ -286,7 +306,11 @@ void __noreturn __pkvm_init_finalise(void) }; pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops; - ret = finalize_host_mappings(); + ret = fix_host_ownership(); + if (ret) + goto out; + + ret = fix_hyp_pgtable_refcnt(); if (ret) goto out;