Re: [PATCH] KVM: x86: Increase the number of fixed MTRR regs to 10

From: Nadav Amit
Date: Mon Aug 18 2014 - 02:39:54 EST


This should have been a benign patch. I'll try to get windows 7 installation disk and check ASAP.

Nadav

> On 18 Aug 2014, at 05:17, Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx> wrote:
>
> Hi Nadav,
>> On Wed, Jun 18, 2014 at 05:21:19PM +0300, Nadav Amit wrote:
>> Recent Intel CPUs have 10 variable range MTRRs. Since operating systems
>> sometime make assumptions on CPUs while they ignore capability MSRs, it is
>> better for KVM to be consistent with recent CPUs. Reporting more MTRRs than
>> actually supported has no functional implications.
>>
>> Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
>> ---
>> arch/x86/include/asm/kvm_host.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
>> index 4931415..0bab29d 100644
>> --- a/arch/x86/include/asm/kvm_host.h
>> +++ b/arch/x86/include/asm/kvm_host.h
>> @@ -95,7 +95,7 @@ static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level)
>> #define KVM_REFILL_PAGES 25
>> #define KVM_MAX_CPUID_ENTRIES 80
>> #define KVM_NR_FIXED_MTRR_REGION 88
>> -#define KVM_NR_VAR_MTRR 8
>> +#define KVM_NR_VAR_MTRR 10
>
> We observed that there is obvious regression caused by this commit, 32bit
> win7 guest show blue screen during boot.
>
> Regards,
> Wanpeng Li
>
>> #define ASYNC_PF_PER_VCPU 64
>>
>> --
>> 1.9.1
>>
>> --
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