KVM: x86: Enable Intel AVX-512 for guest

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>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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 @@
 	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();