On 05/23/2012 05:40 PM, Avi Kivity wrote:
> On 05/23/2012 05:08 PM, Gleb Natapov wrote:
>> "rep ins" emulation is going through emulator now. This is slow because
>> emulator knows how to write back only one datum at a time. This patch
>> provides fast path for the instruction in certain conditions. The
>> conditions are: DF flag is not set, destination memory is RAM and single
>> datum does not cross page boundary. If fast path code fails it falls
>> back to emulation.
>>
>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>> index f75af40..20e3fb0 100644
>> --- a/arch/x86/kvm/svm.c
>> +++ b/arch/x86/kvm/svm.c
>> @@ -1887,21 +1887,31 @@ static int io_interception(struct vcpu_svm *svm)
>> {
>> struct kvm_vcpu *vcpu = &svm->vcpu;
>> u32 io_info = svm->vmcb->control.exit_info_1; /* address size bug? */
>> - int size, in, string;
>> + int size, in, string, rep;
>> unsigned port;
>>
>> ++svm->vcpu.stat.io_exits;
>> string = (io_info & SVM_IOIO_STR_MASK) != 0;
>> + rep = (io_info & SVM_IOIO_REP_MASK) != 0;
>> in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
>> - if (string || in)
>> - return emulate_instruction(vcpu, 0) == EMULATE_DONE;
>>
>
> If decode assists are not available, we still need to emulate, see 15.33.5.
>
Joerg, the 2010 version of the manual says that the effective segment
(10:12) is only available with decode assists. The 2012 version says
it's unconditional. What's correct?
--
error compiling committee.c: too many arguments to function
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