From patchwork Thu Oct 10 18:23:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 13831307 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 962E1D24459 for ; Thu, 10 Oct 2024 23:31:41 +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-Transfer-Encoding:Content-Type:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; 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AJvYcCWrC/JR3jqrfa6CuDus4i73PmkiJu7VUzkemNyjV7KvkH9TKNUE6P7s5Xr6QE/kfzIFRoGWW1FYeZhNFxd4rBb7@lists.infradead.org X-Gm-Message-State: AOJu0YxoUCfCqaUzAC8DLo4TKOYpJzWi/+nR9A07Emcs2OObuZdfN9G4 Rfz1b/NRlvI0FQVPTXD1d1JSe8v+fyrZIHn/3+0YrIbuuaiuGFNgB5QI2UrRi1yapK9ialchfUK Tvg== X-Google-Smtp-Source: AGHT+IEd4uxjZrUyEQQM0MU+jkiJqh3LQboji5/ZXtrCgOTVgrRv0yMO5ln1NKE0y5PwnoqkXxjnsp8xFDc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:9d:3983:ac13:c240]) (user=seanjc job=sendgmr) by 2002:a17:90a:fe86:b0:2da:872e:9ea4 with SMTP id 98e67ed59e1d1-2e2f0d7e9d7mr54a91.3.1728584798284; Thu, 10 Oct 2024 11:26:38 -0700 (PDT) Date: Thu, 10 Oct 2024 11:23:52 -0700 In-Reply-To: <20241010182427.1434605-1-seanjc@google.com> Mime-Version: 1.0 References: <20241010182427.1434605-1-seanjc@google.com> X-Mailer: git-send-email 2.47.0.rc1.288.g06298d1525-goog Message-ID: <20241010182427.1434605-51-seanjc@google.com> Subject: [PATCH v13 50/85] KVM: VMX: Hold mmu_lock until page is released when updating APIC access page 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, " =?utf-8?q?Alex_Benn=C3=A9e?= " , Yan Zhao , David Matlack , David Stevens , Andrew Jones X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241010_112641_414347_13A7488B X-CRM114-Status: GOOD ( 14.25 ) 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 Hold mmu_lock across kvm_release_pfn_clean() when refreshing the APIC access page address to ensure that KVM doesn't mark a page/folio as accessed after it has been unmapped. Practically speaking marking a folio accesses is benign in this scenario, as KVM does hold a reference (it's really just marking folios dirty that is problematic), but there's no reason not to be paranoid (moving the APIC access page isn't a hot path), and no reason to be different from other mmu_notifier-protected flows in KVM. Tested-by: Alex Bennée Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/vmx.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 1a4438358c5e..851be0820e04 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6832,25 +6832,22 @@ void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu) return; read_lock(&vcpu->kvm->mmu_lock); - if (mmu_invalidate_retry_gfn(kvm, mmu_seq, gfn)) { + if (mmu_invalidate_retry_gfn(kvm, mmu_seq, gfn)) kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); - read_unlock(&vcpu->kvm->mmu_lock); - goto out; - } + else + vmcs_write64(APIC_ACCESS_ADDR, pfn_to_hpa(pfn)); - vmcs_write64(APIC_ACCESS_ADDR, pfn_to_hpa(pfn)); - read_unlock(&vcpu->kvm->mmu_lock); - - /* - * No need for a manual TLB flush at this point, KVM has already done a - * flush if there were SPTEs pointing at the previous page. - */ -out: /* * Do not pin apic access page in memory, the MMU notifier * will call us again if it is migrated or swapped out. */ kvm_release_pfn_clean(pfn); + + /* + * No need for a manual TLB flush at this point, KVM has already done a + * flush if there were SPTEs pointing at the previous page. + */ + read_unlock(&vcpu->kvm->mmu_lock); } void vmx_hwapic_isr_update(int max_isr)