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

["Andreas Färber" <afaerber@suse.de>]

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?

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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