From patchwork Sat Oct 20 03:15:34 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Junaid Shahid X-Patchwork-Id: 10650243 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6BFF717D4 for ; Sat, 20 Oct 2018 03:16:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D58020415 for ; Sat, 20 Oct 2018 03:16:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 516EB205F8; Sat, 20 Oct 2018 03:16:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F3F8E20415 for ; Sat, 20 Oct 2018 03:16:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726359AbeJTLY6 (ORCPT ); Sat, 20 Oct 2018 07:24:58 -0400 Received: from mail-pg1-f201.google.com ([209.85.215.201]:47160 "EHLO mail-pg1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725958AbeJTLY5 (ORCPT ); Sat, 20 Oct 2018 07:24:57 -0400 Received: by mail-pg1-f201.google.com with SMTP id o18-v6so25974984pgv.14 for ; Fri, 19 Oct 2018 20:16:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=g+uabJgdq4xSKg/SrBUpc5Tg1R/HrgcxF2oBCcmzsvY=; b=vl/xIQe0v7c4MeeY5TQVogaJD9w6NsdJ2gyRa3v8MOE3/j722JxkqvvZGIMvy0mCfp ODCFoJ9egN/O6k+6mgJWC9GPavaDTuRds1C9I2MSMQ59IXx3EHgfuFLleeV8I9zFq95V 7OEZlgoqGFUWYFpod7O6oONu4K/XTVDaBxd7kX7JbUybxA8NL7igtrw2I0WGtZLorUsV hkuJX7B31ZLJlZaw6dm1f798heUSVInnObfimBE5O6D3YMlxwgAYicKhul/m8imDD3ac 3W+zFy6eOzfG02VCS/NSddl+Uy2rH3vJgXYpQ3p7ZdDPufQ80BrvqVUO1Q+pHd7IhA30 v4mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=g+uabJgdq4xSKg/SrBUpc5Tg1R/HrgcxF2oBCcmzsvY=; b=MPlg7yNLOjdoPde/lka/x3r27HkvmYzXks1zgdFxIlGBhPFV//sRE6c4I69QxCnLWY U/rNFf275yZTeSqlH6porSlM4rPvg4c7v1VgX/voYXO5+zt4E0s7Hvy5HNRQ/8UkhcbN 824CIU0hdYRX2Nclqls4fZBMK7b9Lk5JtQD9urAuxI/EjA0pQAmFm1LJoG2jXozcQRGM X4x/lHQ1kHHqdrxUYwoWR2yZKG5kNvyn01h/cxyThoZnri+YUDO3HXLwSV2XmwWbr7yw 5+XeRoVdj3cVZntrmB3ekqyOjSXn+3+OSsaXi59iRnTg18kSnpjr+yakOyf1RcqgupDu 5vNQ== X-Gm-Message-State: ABuFfojS86bnOJaxLcffNxuQzjkTO7Xumhz6JtbOE7bbuM2a+vfC0Rf2 4SI5/J440ALtjEjAfyINIi2qipzPUY29 X-Google-Smtp-Source: ACcGV6016YGev7vB21ivSRTncYpZSJ4xQASbLJOvdTxSR8UDsN6FJ+TwV7QwGgc93CAwTPPHJCHwrBP66rwi X-Received: by 2002:a62:9c8d:: with SMTP id u13-v6mr17678835pfk.41.1540005365472; Fri, 19 Oct 2018 20:16:05 -0700 (PDT) Date: Fri, 19 Oct 2018 20:15:34 -0700 In-Reply-To: <20181020031543.124399-1-junaids@google.com> Message-Id: <20181020031543.124399-2-junaids@google.com> Mime-Version: 1.0 References: <20181020031543.124399-1-junaids@google.com> X-Mailer: git-send-email 2.19.1.568.g152ad8e336-goog Subject: [PATCH 01/10] kvm: mmu: spte_write_protect optimization From: Junaid Shahid To: pbonzini@redhat.com Cc: kvm@vger.kernel.org, pfeiner@google.com Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This change uses a lighter-weight function instead of mmu_spte_update() in the common case in spte_write_protect(). This helps speed up the get_dirty_log IOCTL. Signed-off-by: Junaid Shahid --- arch/x86/kvm/mmu.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 4cf43ce42959..189e21c77525 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1460,6 +1460,22 @@ static void drop_large_spte(struct kvm_vcpu *vcpu, u64 *sptep) kvm_flush_remote_tlbs(vcpu->kvm); } +static bool spte_test_and_clear_writable(u64 *sptep) +{ + u64 spte = *sptep; + + if (spte & PT_WRITABLE_MASK) { + clear_bit(PT_WRITABLE_SHIFT, (ulong *)sptep); + + if (!spte_ad_enabled(spte)) + kvm_set_pfn_dirty(spte_to_pfn(spte)); + + return true; + } + + return false; +} + /* * Write-protect on the specified @sptep, @pt_protect indicates whether * spte write-protection is caused by protecting shadow page table. @@ -1483,11 +1499,12 @@ static bool spte_write_protect(u64 *sptep, bool pt_protect) rmap_printk("rmap_write_protect: spte %p %llx\n", sptep, *sptep); - if (pt_protect) - spte &= ~SPTE_MMU_WRITEABLE; - spte = spte & ~PT_WRITABLE_MASK; + if (pt_protect) { + spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE); + return mmu_spte_update(sptep, spte); + } - return mmu_spte_update(sptep, spte); + return spte_test_and_clear_writable(sptep); } static bool __rmap_write_protect(struct kvm *kvm,