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Re: [Qemu-devel] Pentium Pro Feature Bugs
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From: |
Paolo Bonzini |
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Subject: |
Re: [Qemu-devel] Pentium Pro Feature Bugs |
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Date: |
Mon, 1 Apr 2019 09:28:49 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 |
On 01/04/19 07:35, Thomas Huth wrote:
> On 01/04/2019 05.36, tedheadster wrote:
>> I just noticed this in the code regarding MMX and I wonder if it is correct:
>>
>> target/i386/cpu.c:
>>
>> #define PPRO_FEATURES (CPUID_FP87 | CPUID_DE | CPUID_PSE | CPUID_TSC | \
>> CPUID_MSR | CPUID_MCE | CPUID_CX8 | CPUID_PGE | CPUID_CMOV | \
>> CPUID_PAT | CPUID_FXSR | CPUID_MMX | CPUID_SSE | CPUID_SSE2 | \
>> CPUID_PAE | CPUID_SEP | CPUID_APIC)
>>
>> The problem I see is that the PentiumPro never supported the MMX
>> instruction extensions (oddly supported in the the Pentium MMX), nor
>> the even later SSE (Pentium III) and SSE2 (Pentium 4) features.
>>
>> Also, the Pentium Pro never officially supported SYSENTER/SYSEXIT
>> (CPUID_SEP), though they originally intended to. Intel discovered
>> shortly before the product release that the hardware didn't work
>> correctly, so they never documented it as a feature to prevent its
>> use.
>>
>> Should these be removed?
>
> Looking at the output of "qemu-system-x86_64 -cpu help", it seems to me
> like QEMU does not emulate the Pention Pro at all. So maybe we should
> simply rename that macro to "QEMU32_FEATURES" or something similar?
Yes, I agree.
Paolo