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Re: [PATCH v7 05/10] x86/vmx: Add Intel Processor Trace support


  • To: Jan Beulich <jbeulich@xxxxxxxx>
  • From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • Date: Fri, 29 Jan 2021 22:08:06 +0000
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On 26/01/2021 13:35, Jan Beulich wrote:
> On 21.01.2021 22:27, Andrew Cooper wrote:
>> --- a/xen/include/asm-x86/msr.h
>> +++ b/xen/include/asm-x86/msr.h
>> @@ -306,6 +306,38 @@ struct vcpu_msrs
>>          };
>>      } misc_features_enables;
>>  
>> +    /*
>> +     * 0x00000560 ... 57x - MSR_RTIT_*
>> +     *
>> +     * "Real Time Instruction Trace", now called Processor Trace.
>> +     *
>> +     * These MSRs are not exposed to guests.  They are controlled by Xen
>> +     * behind the scenes, when vmtrace is enabled for the domain.
>> +     *
>> +     * MSR_RTIT_OUTPUT_BASE not stored here.  It is fixed per vcpu, and
>> +     * derived from v->vmtrace.buf.
>> +     */
>> +    struct {
>> +        /*
>> +         * Placed in the MSR load/save lists.  Only modified by hypercall in
>> +         * the common case.
>> +         */
>> +        uint64_t ctl;
> IIUC this field will be used by subsequent patches only?

Correct.

~Andrew



 


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