From patchwork Fri Jul 26 23:51:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13743525 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CE4ADC3DA49 for ; Sat, 27 Jul 2024 00:18:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To: From:Subject:Message-ID:References:Mime-Version:In-Reply-To:Date: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; 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AJvYcCVTG2pdeYLyLimwZLENY676t92hWEwAm8Ts5hQflG4a+Z+Z2hKq24SX8opKSVF7XT7diPXWhwBBKj2ylDd31N8+NQ9KyoAvRESq1+GregvS+xUpx38= X-Gm-Message-State: AOJu0Ywi9YPLR4gkRscwExD9ryBLnuD40oMvBAar6GC1znQUBCDfGH0h fSgoRcrirY0WLmMWzzdq5Hwcnn5eMglM5FIOKOEiACHxMwwQuL89bT+rRlQBdoRYaSb0D+U9Lz3 Nsw== X-Google-Smtp-Source: AGHT+IFpeG9OHD4NFko0QV+s2bLKC/mOPhRZ2kdDMQUp9/Z6e7qKWnbHym6UcCLJKsXB8YuZDTrWfSN5tHI= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a05:690c:14:b0:66a:764f:e57f with SMTP id 00721157ae682-67a0abd50e9mr49107b3.7.1722038055008; Fri, 26 Jul 2024 16:54:15 -0700 (PDT) Date: Fri, 26 Jul 2024 16:51:56 -0700 In-Reply-To: <20240726235234.228822-1-seanjc@google.com> Mime-Version: 1.0 References: <20240726235234.228822-1-seanjc@google.com> X-Mailer: git-send-email 2.46.0.rc1.232.g9752f9e123-goog Message-ID: <20240726235234.228822-48-seanjc@google.com> Subject: [PATCH v12 47/84] KVM: x86/mmu: Don't mark unused faultin pages as accessed From: Sean Christopherson To: Paolo Bonzini , Marc Zyngier , Oliver Upton , Tianrui Zhao , Bibo Mao , Huacai Chen , Michael Ellerman , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Sean Christopherson Cc: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, David Matlack , David Stevens X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240726_165417_003670_D04FB927 X-CRM114-Status: GOOD ( 13.47 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Sean Christopherson Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org When finishing guest page faults, don't mark pages as accessed if KVM is resuming the guest _without_ installing a mapping, i.e. if the page isn't being used. While it's possible that marking the page accessed could avoid minor thrashing due to reclaiming a page that the guest is about to access, it's far more likely that the gfn=>pfn mapping was was invalidated, e.g. due a memslot change, or because the corresponding VMA is being modified. Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu/mmu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 3cdb1bd80823..95beb50748fc 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4339,7 +4339,9 @@ static void kvm_mmu_finish_page_fault(struct kvm_vcpu *vcpu, * fault handler, and so KVM must (somewhat) speculatively mark the * folio dirty if KVM could locklessly make the SPTE writable. */ - if (!fault->map_writable || r == RET_PF_RETRY) + if (r == RET_PF_RETRY) + kvm_release_page_unused(fault->refcounted_page); + else if (!fault->map_writable) kvm_release_page_clean(fault->refcounted_page); else kvm_release_page_dirty(fault->refcounted_page);