Re: [PATCH] KMV: VMX: consult IA32_VMX_EPT_VPID_CAP to determine EPT paging-structure memory type

[Avi Kivity <avi@redhat.com>]

On 03/22/2010 11:13 AM, Sheng Yang wrote:
>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 06108f3..f971b9b 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -1804,9 +1804,15 @@ static u64 construct_eptp(unsigned long root_hpa)
>>   {
>>   	u64 eptp;
>>
>> -	/* TODO write the value reading from MSR */
>> -	eptp = VMX_EPT_DEFAULT_MT |
>> -		VMX_EPT_DEFAULT_GAW<<  VMX_EPT_GAW_EPTP_SHIFT;
>> +	if (cpu_has_vmx_eptp_writeback())
>> +		eptp = VMX_EPT_MT_WRBACK |
>> +			VMX_EPT_DEFAULT_GAW<<  VMX_EPT_GAW_EPTP_SHIFT;
>>      
> I prefer to ensure WB is supported and used as default. Otherwise it would be
> a big trouble for memory subsystem(to use UC for all memory). Both WB and UC
> EPT memory types are ensured to be support in hardware.
>
> And you can remove VMX_EPT_DEFAULT_MT as well.
>    

I agree, hopefully we never ever see a cpu that doesn't support EPT WB.

-- 
error compiling committee.c: too many arguments to function