Re: [PATCH v2 04/22] KVM: x86: introduce vcpu_gva_to_gpa to cleanup the code

Xiao Guangrong
2011-06-29T11:26:02Z

On 06/29/2011 07:09 PM, Avi Kivity wrote:
> On 06/29/2011 01:56 PM, Xiao Guangrong wrote:
>> On 06/29/2011 04:24 PM, Avi Kivity wrote:
>>
>> >> +static int vcpu_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
>> >> + gpa_t *gpa, struct x86_exception *exception,
>> >> + bool write)
>> >> +{
>> >> + u32 access = (kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0;
>> >> +
>> >> + if (write)
>> >> + access |= PFERR_WRITE_MASK;
>> >
>> > Needs fetch as well so NX/SMEP can work.
>> >
>>
>> This function is only used by read/write emulator, execute permission is
>> not needed for read/write, no?
>
> It's not good to have a function which only implements the functionality partially. It can later be misused.
>
> You can pass the page-fault-error-code instead of the write parameter, I think it will be simpler.
>

Actually, we will get the cache mmio info in this function, i think it is pure waste for other
access execpt mmio, what about change the function name to vcpu_gva_to_gpa_mmio?