On Wed, Mar 03, 2021, Like Xu wrote: > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 034708a3df20..ec4593e0ee6d 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -7268,6 +7268,8 @@ static __init void vmx_set_cpu_caps(void) > supported_xss = 0; > if (!cpu_has_vmx_xsaves()) > kvm_cpu_cap_clear(X86_FEATURE_XSAVES); > + else if (kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR)) > + supported_xss |= XFEATURE_MASK_LBR; > > /* CPUID 0x80000001 */ > if (!cpu_has_vmx_rdtscp()) > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d773836ceb7a..bca2e318ff24 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -10433,6 +10433,8 @@ int kvm_arch_hardware_setup(void *opaque) > > if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES)) > supported_xss = 0; > + else > + supported_xss &= host_xss; Not your fault by any means, but I would prefer to have matching logic for XSS and XCR0. The existing clearing of supported_xss here is pointless. E.g. I'd prefer something like the following, though Paolo may have a different opinion. diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 6d7e760fdfa0..c781034463e5 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7244,12 +7244,15 @@ static __init void vmx_set_cpu_caps(void) kvm_cpu_cap_clear(X86_FEATURE_INVPCID); if (vmx_pt_mode_is_host_guest()) kvm_cpu_cap_check_and_set(X86_FEATURE_INTEL_PT); + if (!cpu_has_vmx_arch_lbr()) { + kvm_cpu_cap_clear(X86_FEATURE_ARCH_LBR); + supported_xss &= ~XFEATURE_MASK_LBR; + } if (vmx_umip_emulated()) kvm_cpu_cap_set(X86_FEATURE_UMIP); /* CPUID 0xD.1 */ - supported_xss = 0; if (!cpu_has_vmx_xsaves()) kvm_cpu_cap_clear(X86_FEATURE_XSAVES); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7b0adebec1ef..5f9eb1f5b840 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -205,6 +205,8 @@ static struct kvm_user_return_msrs __percpu *user_return_msrs; | XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \ | XFEATURE_MASK_PKRU) +#define KVM_SUPPORTED_XSS XFEATURE_MASK_LBR + u64 __read_mostly host_efer; EXPORT_SYMBOL_GPL(host_efer); @@ -8037,6 +8039,11 @@ int kvm_arch_init(void *opaque) supported_xcr0 = host_xcr0 & KVM_SUPPORTED_XCR0; } + if (boot_cpu_has(X86_FEATURE_XSAVES)) + rdmsrl(MSR_IA32_XSS, host_xss); + supported_xss = host_xss & KVM_SUPPORTED_XSS; + } + if (pi_inject_timer == -1) pi_inject_timer = housekeeping_enabled(HK_FLAG_TIMER); #ifdef CONFIG_X86_64 @@ -10412,9 +10419,6 @@ int kvm_arch_hardware_setup(void *opaque) rdmsrl_safe(MSR_EFER, &host_efer); - if (boot_cpu_has(X86_FEATURE_XSAVES)) - rdmsrl(MSR_IA32_XSS, host_xss); - r = ops->hardware_setup(); if (r != 0) return r; @@ -10422,9 +10426,6 @@ int kvm_arch_hardware_setup(void *opaque) memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops)); kvm_ops_static_call_update(); - if (!kvm_cpu_cap_has(X86_FEATURE_XSAVES)) - supported_xss = 0; - #define __kvm_cpu_cap_has(UNUSED_, f) kvm_cpu_cap_has(f) cr4_reserved_bits = __cr4_reserved_bits(__kvm_cpu_cap_has, UNUSED_); #undef __kvm_cpu_cap_has