From 142e4be77bc629802599d7c94f413759bca1c185 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 7 May 2019 09:06:35 -0700 Subject: [PATCH] KVM: nVMX: Update vmcs12 for MSR_IA32_CR_PAT when it's written As alluded to by the TODO comment, KVM unconditionally intercepts writes to the PAT MSR. In the unlikely event that L1 allows L2 to write L1's PAT directly but saves L2's PAT on VM-Exit, update vmcs12 when L2 writes the PAT. This eliminates the need to VMREAD the value from vmcs02 on VM-Exit as vmcs12 is already up to date in all situations. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 4 ---- arch/x86/kvm/vmx/vmx.c | 4 ++++ 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index fb702fa83e06..3290e332c25f 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3564,10 +3564,6 @@ static void sync_vmcs02_to_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs12->guest_ia32_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); } - /* TODO: These cannot have changed unless we have MSR bitmaps and - * the relevant bit asks not to trap the change */ - if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_IA32_PAT) - vmcs12->guest_ia32_pat = vmcs_read64(GUEST_IA32_PAT); if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_IA32_EFER) vmcs12->guest_ia32_efer = vcpu->arch.efer; vmcs12->guest_sysenter_cs = vmcs_read32(GUEST_SYSENTER_CS); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 7ffcbb674b1c..23dd23d7023f 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1910,6 +1910,10 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!kvm_pat_valid(data)) return 1; + if (is_guest_mode(vcpu) && + get_vmcs12(vcpu)->vm_exit_controls & VM_EXIT_SAVE_IA32_PAT) + get_vmcs12(vcpu)->guest_ia32_pat = data; + if (vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_PAT) { vmcs_write64(GUEST_IA32_PAT, data); vcpu->arch.pat = data; -- 2.45.2