[PATCH] x86/cpuid: expose AVX512_4VNNIW and AVX512_4FMAPS features to kvm guest

From: He Chen
Date: Fri Oct 28 2016 - 05:13:32 EST


The spec can be found in Intel Software Developer Manual or in
Instruction Set Extensions Programming Reference.

Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Signed-off-by: He Chen <he.chen@xxxxxxxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index afa7bbb..328b169 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -376,6 +376,10 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* cpuid 7.0.ecx*/
const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | 0 /*OSPKE*/;

+ /* cpuid 7.0.edx*/
+ const u32 kvm_cpuid_7_0_edx_x86_features =
+ 0x4 /* AVX512-4VNNIW */ | 0x8 /* AVX512-4FMAPS */;
+
/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();

@@ -458,12 +462,13 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
/* PKU is not yet implemented for shadow paging. */
if (!tdp_enabled)
entry->ecx &= ~F(PKU);
+ entry->edx &= kvm_cpuid_7_0_edx_x86_features;
} else {
entry->ebx = 0;
entry->ecx = 0;
+ entry->edx = 0;
}
entry->eax = 0;
- entry->edx = 0;
break;
}
case 9:
--
2.7.4