[PATCH v2 2/2] KVM: Mask KVM_GET_SUPPORTED_CPUID data with Linux cpuid info

[Avi Kivity <avi@redhat.com>]

This allows Linux to mask cpuid bits if, for example, nx is enabled on only
some cpus.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
 arch/x86/kvm/x86.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2044302..788f064 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2229,6 +2229,11 @@ out:
 	return r;
 }
 
+static void cpuid_mask(u32 *word, int wordnum)
+{
+	*word &= boot_cpu_data.x86_capability[wordnum];
+}
+
 static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 			   u32 index)
 {
@@ -2303,7 +2308,9 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		break;
 	case 1:
 		entry->edx &= kvm_supported_word0_x86_features;
+		cpuid_mask(&entry->edx, 0);
 		entry->ecx &= kvm_supported_word4_x86_features;
+		cpuid_mask(&entry->ecx, 4);
 		/* we support x2apic emulation even if host does not support
 		 * it since we emulate x2apic in software */
 		entry->ecx |= F(X2APIC);
@@ -2394,7 +2401,9 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 		break;
 	case 0x80000001:
 		entry->edx &= kvm_supported_word1_x86_features;
+		cpuid_mask(&entry->edx, 1);
 		entry->ecx &= kvm_supported_word6_x86_features;
+		cpuid_mask(&entry->ecx, 6);
 		break;
 	}
 
-- 
1.7.3.1