2016-04-15 13:54-0300, Eduardo Habkost:
> On Thu, Apr 14, 2016 at 10:55:07PM +0200, Radim Krčmář wrote:
>> QEMU complains about -cpu host on an AMD machine:
>> warning: host doesn't support requested feature: CPUID.80000001H:EDX [bit
>> 0]
>> For bits 0,1,3,4,5,6,7,8,9,12,13,14,15,16,17,23,24.
>>
>> Host does support them, but x86_cpu_get_migratable_flags filters unnamed
>> features and drops these bits without realizing that they are aliases to
>> CPUID.1H:EDX and have their names there.
>>
>> See https://bugzilla.redhat.com/show_bug.cgi?id=1326721 for details.
>>
>> Signed-off-by: Radim Krčmář <rkrc...@redhat.com>
>> ---
>> target-i386/cpu.c | 40 ++++++++++++++++++++++------------------
>> 1 file changed, 22 insertions(+), 18 deletions(-)
>
> I don't think we need that complexity to fix the problem. We even
> have a similar hack in kvm_arch_get_supported_cpuid() to make
> sure it handles the alias bits properly. Instead of hacking those
> functions to copy CPUID[1] data, it's much easier to simply copy
> the alias bits in realizefn after we call
> x86_cpu_filter_features(), not before.
>
> The following (untested) fix should be sufficient:
It is,
Tested-by: Radim Krčmář <rkrc...@redhat.com>
Thank you.
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index ddae932..d0b5b69 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2897,6 +2897,14 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
> env->cpuid_level = 7;
> }
>
> + if (x86_cpu_filter_features(cpu) && cpu->enforce_cpuid) {
> + error_setg(&local_err,
> + kvm_enabled() ?
> + "Host doesn't support requested features" :
> + "TCG doesn't support requested features");
> + goto out;
> + }
> +
> /* On AMD CPUs, some CPUID[8000_0001].EDX bits must match the bits on
> * CPUID[1].EDX.
> */
> @@ -2907,14 +2915,6 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
> }
>
>
> - if (x86_cpu_filter_features(cpu) && cpu->enforce_cpuid) {
> - error_setg(&local_err,
> - kvm_enabled() ?
> - "Host doesn't support requested features" :
> - "TCG doesn't support requested features");
> - goto out;
> - }
> -
> #ifndef CONFIG_USER_ONLY
> qemu_register_reset(x86_cpu_machine_reset_cb, cpu);
>
>
>
> --
> Eduardo
