Re: [PATCH] kvm: fix cpuid eax

From: Anthony Liguori
Date: Mon Apr 30 2012 - 16:37:19 EST


On 04/30/2012 09:39 AM, Michael S. Tsirkin wrote:
cpuid eax should return the max leaf so that
guests can find out the valid range.
This matches Xen et al.

What KVM does here predates Xen and Hyper-V.

This is an ABI breaker.

Regards,

Anthony Liguori


Tested using -cpu host.

Signed-off-by: Michael S. Tsirkin<mst@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 7d00d2d..bda4877 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -397,7 +397,7 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
case KVM_CPUID_SIGNATURE: {
char signature[12] = "KVMKVMKVM\0\0";
u32 *sigptr = (u32 *)signature;
- entry->eax = 0;
+ entry->eax = KVM_CPUID_FEATURES;
entry->ebx = sigptr[0];
entry->ecx = sigptr[1];
entry->edx = sigptr[2];

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