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);
+
} 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
