On Mon, Feb 25, 2019 at 09:27:11PM +0800, Yang Weijiang wrote:
> Guest CET SHSTK and IBT capability are reported via
> CPUID.(EAX=7, ECX=0):ECX[bit 7] and EDX[bit 20] respectively.
> Guest user mode and supervisor mode xsaves component size
> is reported via CPUID.(EAX=0xD, ECX=1):ECX[bit 11] and ECX[bit 12]
> respectively.
>
> Signed-off-by: Zhang Yi Z <yi.z.zhang@xxxxxxxxxxxxxxx>
> Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
> ---
> arch/x86/kvm/cpuid.c | 60 +++++++++++++++++++++++++++++++++-----------
> arch/x86/kvm/x86.h | 4 +++
> 2 files changed, 50 insertions(+), 14 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index cb1aece25b17..5e05756cc6db 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -65,6 +65,16 @@ u64 kvm_supported_xcr0(void)
> return xcr0;
> }
>
> +u64 kvm_supported_xss(void)
> +{
> + u64 xss;
> +
> + rdmsrl(MSR_IA32_XSS, xss);
> + xss &= KVM_SUPPORTED_XSS;
> + return xss;
> +}
> +EXPORT_SYMBOL(kvm_supported_xss);
> +
> #define F(x) bit(X86_FEATURE_##x)
>
> /* For scattered features from cpufeatures.h; we currently expose none */
> @@ -323,6 +333,7 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> u32 index, int *nent, int maxnent)
> {
> int r;
> + u32 eax, ebx, ecx, edx;
> unsigned f_nx = is_efer_nx() ? F(NX) : 0;
> #ifdef CONFIG_X86_64
> unsigned f_gbpages = (kvm_x86_ops->get_lpage_level() == PT_PDPE_LEVEL)
> @@ -503,6 +514,20 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> * if the host doesn't support it.
> */
> entry->edx |= F(ARCH_CAPABILITIES);
> +
> + /*
> + * Guest OS CET enabling is designed independent to
> + * host enabling, it only has dependency on Host HW
> + * capability, if it has, report CET support to
> + * Guest.
> + */
> + cpuid_count(7, 0, &eax, &ebx, &ecx, &edx);
> + if (ecx & F(SHSTK))
> + entry->ecx |= F(SHSTK);
> +
> + if (edx & F(IBT))
> + entry->edx |= F(IBT);
There's no need to manually add these flags. They will be automatically
kept if supported in hardware because your previous patch, 02/08, added
them to the mask of features that can be exposed to the guest,
i.e. set them in kvm_cpuid_7_0_e{c,d}x_x86_features.
> +
> } else {
> entry->ebx = 0;
> entry->ecx = 0;
> @@ -564,14 +589,17 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> }
> case 0xd: {
> int idx, i;
> - u64 supported = kvm_supported_xcr0();
> + u64 u_supported = kvm_supported_xcr0();
> + u64 s_supported = kvm_supported_xss();
> + u64 supported;
> + int compacted;
>
> - entry->eax &= supported;
> - entry->ebx = xstate_required_size(supported, false);
> + entry->eax &= u_supported;
> + entry->ebx = xstate_required_size(u_supported, false);
> entry->ecx = entry->ebx;
> - entry->edx &= supported >> 32;
> + entry->edx &= u_supported >> 32;
> entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> - if (!supported)
> + if (!u_supported && !s_supported)
> break;
>
> for (idx = 1, i = 1; idx < 64; ++idx) {
> @@ -583,19 +611,23 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
> if (idx == 1) {
> entry[i].eax &= kvm_cpuid_D_1_eax_x86_features;
> cpuid_mask(&entry[i].eax, CPUID_D_1_EAX);
> - entry[i].ebx = 0;
> - if (entry[i].eax & (F(XSAVES)|F(XSAVEC)))
> - entry[i].ebx =
> - xstate_required_size(supported,
> - true);
> + supported = u_supported | s_supported;
> + compacted = entry[i].eax &
> + (F(XSAVES) | F(XSAVEC));
> + entry[i].ebx = xstate_required_size(supported,
> + compacted);
> + entry[i].ecx &= s_supported;
> + entry[i].edx = 0;
> } else {
> + supported = (entry[i].ecx & 1) ? s_supported :
> + u_supported;
> if (entry[i].eax == 0 || !(supported & mask))
> continue;
> - if (WARN_ON_ONCE(entry[i].ecx & 1))
> - continue;
> + entry[i].ecx &= 1;
> + entry[i].edx = 0;
> + if (entry[i].ecx)
> + entry[i].ebx = 0;
> }
> - entry[i].ecx = 0;
> - entry[i].edx = 0;
> entry[i].flags |=
> KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
> ++*nent;
> diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
> index 224cd0a47568..c61da41c3c5c 100644
> --- a/arch/x86/kvm/x86.h
> +++ b/arch/x86/kvm/x86.h
> @@ -283,6 +283,10 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
> | XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
> | XFEATURE_MASK_BNDCSR | XFEATURE_MASK_AVX512 \
> | XFEATURE_MASK_PKRU)
> +
> +#define KVM_SUPPORTED_XSS (XFEATURE_MASK_SHSTK_USER \
> + | XFEATURE_MASK_SHSTK_KERNEL)
> +
> extern u64 host_xcr0;
>
> extern u64 kvm_supported_xcr0(void);
> --
> 2.17.1
>
