On 26/12/18 09:15, Yang Weijiang wrote: > Guest OS can query CET SHSTK and IBT support by CPUID.(EAX=0x7,ECX=0), > in return, ECX[bit 7] corresponds to SHSTK feature, and EDX[bit 20] > corresponds to IBT feature. > > Signed-off-by: Zhang Yi Z <yi.z.zhang@xxxxxxxxxxxxxxx> > Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx> > --- > arch/x86/kvm/cpuid.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 55c282f71f93..d7b60b3c4326 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -67,6 +67,8 @@ u64 kvm_supported_xcr0(void) > > #define F(x) bit(X86_FEATURE_##x) > > +#define CET_IBT_BIT bit(20) > + > /* For scattered features from cpufeatures.h; we currently expose none */ > #define KF(x) bit(KVM_CPUID_BIT_##x) > > @@ -407,12 +409,12 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, > F(AVX512VBMI) | F(LA57) | F(PKU) | 0 /*OSPKE*/ | > F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) | > F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) | > - F(CLDEMOTE); > + F(CLDEMOTE) | F(SHSTK); > > /* cpuid 7.0.edx*/ > const u32 kvm_cpuid_7_0_edx_x86_features = > F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) | > - F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES); > + F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | CET_IBT_BIT; > > /* all calls to cpuid_count() should be made on the same cpu */ > get_cpu(); > This might change soon, but at least for now KVM's XSAVES/XRSTORS usage depends on Linux's. Therefore, this should only be enabled if Linux has set bits 11 and 12 in MSR_IA32_XSS. Paolo
