On Thu, Mar 26, 2020 at 04:18:46PM +0800, Yang Weijiang wrote:
> Set the feature bits so that CET capabilities can be seen
> in guest via CPUID enumeration. Add CR4.CET bit support
> in order to allow guest set CET master control bit(CR4.CET).
>
> Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 3 ++-
> arch/x86/kvm/cpuid.c | 4 ++++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 2c944ad99692..5109c43c6981 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -95,7 +95,8 @@
> | X86_CR4_PGE | X86_CR4_PCE | X86_CR4_OSFXSR | X86_CR4_PCIDE \
> | X86_CR4_OSXSAVE | X86_CR4_SMEP | X86_CR4_FSGSBASE \
> | X86_CR4_OSXMMEXCPT | X86_CR4_LA57 | X86_CR4_VMXE \
> - | X86_CR4_SMAP | X86_CR4_PKE | X86_CR4_UMIP))
> + | X86_CR4_SMAP | X86_CR4_PKE | X86_CR4_UMIP \
> + | X86_CR4_CET))
>
> #define CR8_RESERVED_BITS (~(unsigned long)X86_CR8_TPR)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 25e9a11291b3..26ab959df92f 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -366,6 +366,10 @@ void kvm_set_cpu_caps(void)
> kvm_cpu_cap_set(X86_FEATURE_INTEL_STIBP);
> if (boot_cpu_has(X86_FEATURE_AMD_SSBD))
> kvm_cpu_cap_set(X86_FEATURE_SPEC_CTRL_SSBD);
> + if (boot_cpu_has(X86_FEATURE_IBT))
> + kvm_cpu_cap_set(X86_FEATURE_IBT);
> + if (boot_cpu_has(X86_FEATURE_SHSTK))
> + kvm_cpu_cap_set(X86_FEATURE_SHSTK);
This is the wrong way to advertise bits, the correct method is to declare
the flag in the appriorate kvm_cpu_cap_mask() call. The manually handling
is only needed when the feature bit diverges from kernel support, either
because KVM allow a feature based purely on hardware support, e.g. LA57, or
when emulating a feature based on a different similar feature, e.g. the
STIBP/SSBD flags above.
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6828be99b908..6262438f9527 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -329,7 +329,8 @@ void kvm_set_cpu_caps(void)
F(AVX512VBMI) | F(LA57) | 0 /*PKU*/ | 0 /*OSPKE*/ | F(RDPID) |
F(AVX512_VPOPCNTDQ) | F(UMIP) | F(AVX512_VBMI2) | F(GFNI) |
F(VAES) | F(VPCLMULQDQ) | F(AVX512_VNNI) | F(AVX512_BITALG) |
- F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/
+ F(CLDEMOTE) | F(MOVDIRI) | F(MOVDIR64B) | 0 /*WAITPKG*/ |
+ F(SHSTK)
);
/* Set LA57 based on hardware capability. */
if (cpuid_ecx(7) & F(LA57))
@@ -338,7 +339,7 @@ void kvm_set_cpu_caps(void)
kvm_cpu_cap_mask(CPUID_7_EDX,
F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES) | F(INTEL_STIBP) |
- F(MD_CLEAR) | F(AVX512_VP2INTERSECT) | F(FSRM)
+ F(MD_CLEAR) | F(AVX512_VP2INTERSECT) | F(FSRM) | F(IBT)
);
>
> kvm_cpu_cap_mask(CPUID_7_1_EAX,
> F(AVX512_BF16)
> --
> 2.17.2
>
