From: Sean Christopherson Date: Tue, 7 May 2019 16:06:35 +0000 (-0700) Subject: KVM: nVMX: Update vmcs12 for MSR_IA32_CR_PAT when it's written X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=142e4be77bc629802599d7c94f413759bca1c185;p=linux.git 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 --- diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index fb702fa83e06c..3290e332c25ff 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 7ffcbb674b1cf..23dd23d7023f4 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;