Re: [Xen-devel] [PATCH RFC 3/9] xen: Force-enable relevant MSR events; optimize the number of sent MSR events

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.07.14 at 17:35, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 02/07/14 14:33, Razvan Cojocaru wrote:
>> @@ -700,6 +700,25 @@ void vmx_disable_intercept_for_msr(struct vcpu *v, u32 
>> msr, int type)
>>      if ( msr_bitmap == NULL )
>>          return;
>>  
>> +    /* Filter out MSR-s needed by the memory introspection engine */
>> +    switch ( msr )
>> +    {
>> +    case MSR_IA32_SYSENTER_EIP:
>> +    case MSR_IA32_SYSENTER_ESP:
>> +    case MSR_IA32_SYSENTER_CS:
>> +    case MSR_IA32_MC0_CTL:
>> +    case MSR_STAR:
>> +    case MSR_LSTAR:
>> +
> 
> Given the performance implications of forcing interception of these
> MSRs, it would be gated on mem_access being active for the domain.

Absolutely.

>> +        printk("Warning: cannot disable the interception of MSR "
>> +            "0x%08x because it is needed by the memory introspection "
>> +            "engine\n", msr);
>> +        return;
> 
> gdprintk() please, and a rather shorter message.

Not sure about gdprintk() - we neither need the file/line to be printed
here, nor am I sure that v == current (or else the dom/vcpu printed
would be wrong), but this should clearly be XENLOG_DEBUG and
abbreviated as much as possible without making it meaningless.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel