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Subject[PATCH] KVM: x86: Enable Intel AVX-512 for guest
Date
Expose Intel AVX-512 feature bits to guest. Also add checks for
xcr0 AVX512 related bits according to spec:
http://download-software.intel.com/sites/default/files/managed/71/2e/319433-017.pdf

Signed-off-by: Chao Peng <chao.p.peng@linux.intel.com>
---
arch/x86/include/asm/xsave.h | 1 +
arch/x86/kvm/cpuid.c | 3 ++-
arch/x86/kvm/x86.c | 6 ++++++
arch/x86/kvm/x86.h | 3 ++-
4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h
index 7e7a79a..5fa9770 100644
--- a/arch/x86/include/asm/xsave.h
+++ b/arch/x86/include/asm/xsave.h
@@ -16,6 +16,7 @@
#define XSTATE_Hi16_ZMM 0x80

#define XSTATE_FPSSE (XSTATE_FP | XSTATE_SSE)
+#define XSTATE_AVX512 (XSTATE_OPMASK | XSTATE_ZMM_Hi256 | XSTATE_Hi16_ZMM)
/* Bit 63 of XCR0 is reserved for future expansion */
#define XSTATE_EXTEND_MASK (~(XSTATE_FPSSE | (1ULL << 63)))

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 976e3a5..20d8321 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -317,7 +317,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
const u32 kvm_supported_word9_x86_features =
F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
- F(ADX) | F(SMAP);
+ F(ADX) | F(SMAP) | F(AVX512F) | F(AVX512PF) | F(AVX512ER) |
+ F(AVX512CD);

/* all calls to cpuid_count() should be made on the same cpu */
get_cpu();
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5430e4b..3d77b88 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -651,6 +651,12 @@ int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr)
if ((!(xcr0 & XSTATE_BNDREGS)) != (!(xcr0 & XSTATE_BNDCSR)))
return 1;

+ if (xcr0 & XSTATE_AVX512) {
+ if (!(xcr0 & XSTATE_YMM))
+ return 1;
+ if ((xcr0 & XSTATE_AVX512) != XSTATE_AVX512)
+ return 1;
+ }
kvm_put_guest_xcr0(vcpu);
vcpu->arch.xcr0 = xcr0;

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 7cb9c45..cc1d61a 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -162,7 +162,8 @@ int kvm_write_guest_virt_system(struct x86_emulate_ctxt *ctxt,
bool kvm_mtrr_valid(struct kvm_vcpu *vcpu, u32 msr, u64 data);

#define KVM_SUPPORTED_XCR0 (XSTATE_FP | XSTATE_SSE | XSTATE_YMM \
- | XSTATE_BNDREGS | XSTATE_BNDCSR)
+ | XSTATE_BNDREGS | XSTATE_BNDCSR \
+ | XSTATE_AVX512)
extern u64 host_xcr0;

extern u64 kvm_supported_xcr0(void);
--
1.7.9.5


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