On 30/10/2017 23:05, Luwei Kang wrote: > From: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx> > > L1 hypervisor can't get the capability of "TraceEn can be > set in VMX operation"(IA32_VMX_MISC[14]=0) and any attempt > to set IA32_RTIT_CTL.TraceEn in VMX operation using WRMSR > will cause a general-protection exception if IA32_VMX_MISC[14] > is 0. So we need to leave out write this msr in L1 VMX > operation. > > Signed-off-by: Chao Peng <chao.p.peng@xxxxxxxxxxxxxxx> > Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx> > --- > arch/x86/kvm/vmx.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 091120e..8f61a8d 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -936,6 +936,7 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu, > static void vmx_set_nmi_mask(struct kvm_vcpu *vcpu, bool masked); > static bool nested_vmx_is_page_fault_vmexit(struct vmcs12 *vmcs12, > u16 error_code); > +static bool vmx_pt_supported(void); > > static DEFINE_PER_CPU(struct vmcs *, vmxarea); > static DEFINE_PER_CPU(struct vmcs *, current_vmcs); > @@ -3384,6 +3385,11 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > return 1; > msr_info->data = vcpu->arch.ia32_xss; > break; > + case MSR_IA32_RTIT_CTL: > + if (!vmx_pt_supported()) > + return 1; > + msr_info->data = vmcs_read64(GUEST_IA32_RTIT_CTL); > + break; > case MSR_TSC_AUX: > if (!msr_info->host_initiated && > !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP)) > @@ -3508,6 +3514,11 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > else > clear_atomic_switch_msr(vmx, MSR_IA32_XSS); > break; > + case MSR_IA32_RTIT_CTL: > + if (!vmx_pt_supported() || to_vmx(vcpu)->nested.vmxon) > + return 1; VMXON must also clear TraceEn bit (see 23.4 in the SDM). You also need to support R/W of all the other MSRs, in order to make them accessible to userspace, and add them in msrs_to_save and kvm_init_msr_list. Regarding the save/restore of the state, I am now wondering if you could also use XSAVES and XRSTORS instead of multiple rdmsr/wrmsr in a loop. The cost is two MSR writes on vmenter (because the guest must run with IA32_XSS=0) and two on vmexit. Thanks, Paolo > + vmcs_write64(GUEST_IA32_RTIT_CTL, data); > + break; > case MSR_TSC_AUX: > if (!msr_info->host_initiated && > !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP)) >
