[Qemu-devel] Re: [PATCH][STABLE] fix CPUID vendor override

[Avi Kivity]

On 04/11/2010 10:21 PM, Andre Przywara wrote:
> the meaning of vendor_override is actually the opposite of how it
> is currently used :-(
> Fix it to allow KVM to export the non-native CPUID vendor if
> explicitly requested by the user.
>
> Signed-off-by: Andre Przywara<address@hidden>
> ---
>   target-i386/helper.c |    2 +-
>   1 files changed, 1 insertions(+), 1 deletions(-)
>
> I will send a refactoring patch including this fix for git HEAD later.
>
> Regards,
> Andre.
>
> diff --git a/target-i386/helper.c b/target-i386/helper.c
> index 9d7fec3..c17adc1 100644
> --- a/target-i386/helper.c
> +++ b/target-i386/helper.c
> @@ -1655,7 +1655,7 @@ static void get_cpuid_vendor(CPUX86State *env, uint32_t 
> *ebx,
>        * this if you want to use KVM's sysenter/syscall emulation
>        * in compatibility mode and when doing cross vendor migration
>        */
> -    if (kvm_enabled()&&  env->cpuid_vendor_override) {
> +    if (kvm_enabled()&&  ! env->cpuid_vendor_override) {
>           host_cpuid(0, 0, NULL, ebx, ecx, edx);
>       }
>   }
>    

Why is the original code wrong?  I would say vendor_override means 
overriding the qemu-picked vendor ID in favour of the host cpuid.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.