On Wed, Jun 04, 2014 at 03:17:56AM -0400, Jidong Xiao wrote: > On Wed, Jun 4, 2014 at 3:09 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > Il 04/06/2014 03:10, Jidong Xiao ha scritto: > > > >> diff --git a/qemu-2.0.0/target-i386/kvm.c.orig > >> b/qemu-2.0.0/target-i386/kvm.c > >> index 4389959..b8b282d 100644 > >> --- a/qemu-2.0.0/target-i386/kvm.c.orig > >> +++ b/qemu-2.0.0/target-i386/kvm.c > >> @@ -530,7 +530,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > >> memcpy(signature, "KVMKVMKVM\0\0\0", 12); > >> c = &cpuid_data.entries[cpuid_i++]; > >> c->function = KVM_CPUID_SIGNATURE | kvm_base; > >> - c->eax = 0; > >> + c->eax = KVM_CPUID_FEATURES; > >> c->ebx = signature[0]; > >> c->ecx = signature[1]; > >> c->edx = signature[2]; > > > > > > This should actually be "KVM_CPUID_FEATURES | kvm_base", in case Hyper-V > > leaves are available too. But it is a good catch! > > > > Paolo > > > Thanks Paolo. I have just added that and resend the patch as following: > > -Jidong > > === > Signed-off-by: Jidong Xiao <jidong.xiao@xxxxxxxxx> > > --- > diff --git a/qemu-2.0.0/target-i386/kvm.c.orig b/qemu-2.0.0/target-i386/kvm.c > index 4389959..fe49a75 100644 > --- a/qemu-2.0.0/target-i386/kvm.c.orig > +++ b/qemu-2.0.0/target-i386/kvm.c > @@ -530,7 +530,7 @@ int kvm_arch_init_vcpu(CPUState *cs) > memcpy(signature, "KVMKVMKVM\0\0\0", 12); > c = &cpuid_data.entries[cpuid_i++]; > c->function = KVM_CPUID_SIGNATURE | kvm_base; > - c->eax = 0; > + c->eax = KVM_CPUID_FEATURES | kvm_base; This makes the CPUID data change under the guest's feet during live-migration. Adding compat code to ensure older machine-types keep the old behavior is necessary, but in this specific case it is mostly harmless because 0x0 is documented as being equivalent to 0x40000001. (But I don't know how guests are supposed to behave when they see CPUID[KVM_CPUID_SIGNATURE_NEXT].EAX==0.) -- Eduardo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
