[Qemu-devel] [PATCH v2] Work around misreported kvm cpuid features

[Avi Kivity]

kvm misreports MCA, MCE, MTRR, and PAT as unsupported.  This causes Vista to
fail.  Since QEMU does not support any version of kvm that does not actually
support these features, it is safe to enable them unconditionally.

These features are needed by Vista x64 to boot.

Signed-off-by: Avi Kivity <address@hidden>
---

Changes from v1:
- use CPUID_* instead of open coding constants

 target-i386/kvm.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index fe67eed..86da72d 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -88,6 +88,10 @@ uint32_t kvm_arch_get_supported_cpuid(CPUState *env, 
uint32_t function, int reg)
                 break;
             case R_EDX:
                 ret = cpuid->entries[i].edx;
+                if (function == 1) {
+                    /* kvm misreports the following features: */
+                    ret |= CPUID_MTRR | CPUID_PAT | CPUID_MCA | CPUID_MCE;
+                }
                 if (function == 0x80000001) {
                     /* On Intel, kvm returns cpuid according to the Intel spec,
                      * so add missing bits according to the AMD spec:
-- 
1.6.0.6