> > 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). Will clear TraceEn bit in handle_vmon() function. > > 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. > Will add it in next version. This is use for live migration, is that right? > 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. > If use XSAVES and XRSTORS for context switch. 1. Before kvm_load_guest_fpu(vcpu), we need to save host RTIT_CTL, disable PT and restore the value of "vmx->pt_desc.guest.ctl" to GUEST_IA32_RTIT_CTL. Is that right? 2. After VM-exit (step out from kvm_x86_ops->run(vcpu)), we need to save the status of GUEST_IA32_RTIT_CTL . TRACEEN=0 and others MSRs are still in guest status. Where to enable PT if in host-guest mode. I think we should enable PT after vm-exit but it may cause #GP. " If XRSTORS would restore (or initialize) PT state and IA32_RTIT_CTL.TraceEn = 1, the instruction causes a general-protection exception. SDM 13.5.6". if enable after kvm_put_guest_fpu() I think it too late.) Thanks, Luwei Kang > > > + vmcs_write64(GUEST_IA32_RTIT_CTL, data); > > + break; > > case MSR_TSC_AUX: > > if (!msr_info->host_initiated && > > !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP)) > >
