Re: [Qemu-devel] [PATCH] target-i386: set model=6 on qemu64 & qemu32 CPU models

["Andreas Färber" <afaerber@suse.de>]

Am 11.09.2013 10:37, schrieb Igor Mammedov:
> On Wed, 11 Sep 2013 10:25:58 +0200
> Andreas Färber <afaerber@suse.de> wrote:
> 
>> Am 11.09.2013 10:22, schrieb Igor Mammedov:
>>> On Tue, 10 Sep 2013 17:48:59 -0300
>>> Eduardo Habkost <ehabkost@redhat.com> wrote:
>>>
>>>> There's no Intel CPU with family=6,model=2, and Linux and Windows guests
>>>> disable SEP when seeing that combination due to Pentium Pro erratum #82.
>>>>
>>>> In addition to just having SEP ignored by guests, Skype (and maybe other
>>>> applications) runs sysenter directly without passing through ntdll on
>>>> Windows, and crashes because Windows ignored the SEP CPUID bit.
>>>>
>>>> So, having model > 2 is a better default on qemu64 and qemu32 for two
>>>> reasons: making SEP really available for guests, and avoiding crashing
>>>> applications that work on bare metal.
>>>>
>>>> model=3 would fix the problem, but it causes CPU enumeration problems
>>>> for Windows guests[1]. So this patch sets model=6, that matches "Athlon
>>>> (PM core)" on AMD and "P2 with on-die L2 cache" on Intel and it allows
>>>> Windows to use all CPUs as well as fixing sysenter.
>>>>
>>>> [1] https://bugzilla.redhat.com/show_bug.cgi?id=508623
>>>>
>>>> Cc: Andrea Arcangeli <aarcange@redhat.com>
>>>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>>>> ---
>>>>  include/hw/i386/pc.h | 8 ++++++++
>>>>  target-i386/cpu.c    | 4 ++--
>>>>  2 files changed, 10 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
>>>> index 7fb04d8..195e962 100644
>>>> --- a/include/hw/i386/pc.h
>>>> +++ b/include/hw/i386/pc.h
>>>> @@ -258,6 +258,14 @@ int e820_add_entry(uint64_t, uint64_t, uint32_t);
>>>>              .driver = TYPE_X86_CPU,\
>>>>              .property = "pmu",\
>>>>              .value = "on",\
>>>> +        },{\
>>>> +            .driver   = "qemu64-" TYPE_X86_CPU,\
>>>> +            .property = "model",\
>>>> +            .value    = stringify(2),\
>>>> +        },{\
>>>> +            .driver   = "qemu32-" TYPE_X86_CPU,\
>>>> +            .property = "model",\
>>>> +            .value    = stringify(3),\
>>>>          }
>>>>  
>>>>  #define PC_COMPAT_1_4 \
>>
>> Shouldn't this hunk be in PC_COMPAT_1_6 rather than alongside PMU, which
>> I believe was for 1_5?
> grr, you are right.
> my reviewed-by stands, provided compats are moved to PC_COMPAT_1_6.

Fixed now that Stefan's net-next pull has been merged. Thanks, applied
to qom-cpu:
https://github.com/afaerber/qemu-cpu/commits/qom-cpu

Andreas

> 
> 
>> Andreas
>>
>>>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>>>> index c36345e..36cfbce 100644
>>>> --- a/target-i386/cpu.c
>>>> +++ b/target-i386/cpu.c
>>>> @@ -544,7 +544,7 @@ static x86_def_t builtin_x86_defs[] = {
>>>>          .level = 4,
>>>>          .vendor = CPUID_VENDOR_AMD,
>>>>          .family = 6,
>>>> -        .model = 2,
>>>> +        .model = 6,
>>>>          .stepping = 3,
>>>>          .features[FEAT_1_EDX] =
>>>>              PPRO_FEATURES |
>>>> @@ -647,7 +647,7 @@ static x86_def_t builtin_x86_defs[] = {
>>>>          .level = 4,
>>>>          .vendor = CPUID_VENDOR_INTEL,
>>>>          .family = 6,
>>>> -        .model = 3,
>>>> +        .model = 6,
>>>>          .stepping = 3,
>>>>          .features[FEAT_1_EDX] =
>>>>              PPRO_FEATURES,
>>>
>>> Reviewed-By: Igor Mammedov <imammedo@redhat.com>
>>>
>>
>>
> 


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