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

Avi Kivity
2010-10-24T13:38:48Z

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 48ce015..54fda7e 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->edx, 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->edx, 6);
break;
}

--
1.7.3.1