From 7afe79f5734aebb55895424074bb944ac4717b7d Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 10 Oct 2024 11:23:34 -0700 Subject: [PATCH] KVM: nVMX: Mark vmcs12's APIC access page dirty when unmapping MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Mark the APIC access page as dirty when unmapping it from KVM. The fact that the page _shouldn't_ be written doesn't guarantee the page _won't_ be written. And while the contents are likely irrelevant, the values _are_ visible to the guest, i.e. dropping writes would be visible to the guest (though obviously highly unlikely to be problematic in practice). Marking the map dirty will allow specifying the write vs. read-only when *mapping* the memory, which in turn will allow creating read-only maps. Tested-by: Alex Bennée Signed-off-by: Sean Christopherson Tested-by: Dmitry Osipenko Signed-off-by: Paolo Bonzini Message-ID: <20241010182427.1434605-33-seanjc@google.com> --- arch/x86/kvm/vmx/nested.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 81865db18e129..ff83b56fe2fa2 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -318,12 +318,7 @@ static void nested_put_vmcs12_pages(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - /* - * Unpin physical memory we referred to in the vmcs02. The APIC access - * page's backing page (yeah, confusing) shouldn't actually be accessed, - * and if it is written, the contents are irrelevant. - */ - kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map, false); + kvm_vcpu_unmap(vcpu, &vmx->nested.apic_access_page_map, true); kvm_vcpu_unmap(vcpu, &vmx->nested.virtual_apic_map, true); kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true); vmx->nested.pi_desc = NULL; -- 2.47.3