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Re: [Qemu-devel] [PATCH] target-i386: set model=6 on qemu64 & qemu32 CPU
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH] target-i386: set model=6 on qemu64 & qemu32 CPU models |
Date: |
Wed, 11 Sep 2013 10:25:58 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 |
Am 11.09.2013 10:22, schrieb Igor Mammedov:
> On Tue, 10 Sep 2013 17:48:59 -0300
> Eduardo Habkost <address@hidden> 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 <address@hidden>
>> Signed-off-by: Eduardo Habkost <address@hidden>
>> ---
>> 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 <address@hidden>
>
--
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