Re: [Xen-devel] [PATCH 1/7] x86/ucode: Document the behaviour of the microcode_ops hooks

[Jan Beulich <jbeulich@xxxxxxxx>]

On 23.03.2020 14:26, Andrew Cooper wrote:
> On 23/03/2020 12:33, Jan Beulich wrote:
>> On 23.03.2020 11:17, Andrew Cooper wrote:
>>> --- a/xen/include/asm-x86/microcode.h
>>> +++ b/xen/include/asm-x86/microcode.h
>>> @@ -7,8 +7,13 @@
>>>  #include <public/xen.h>
>>>  
>>>  struct cpu_signature {
>>> +    /* CPU signature (CPUID.1.EAX).  Only written on Intel. */
>>>      unsigned int sig;
>>> +
>>> +    /* Platform Flags (only actually 1 bit).  Only applicable to Intel. */
>>>      unsigned int pf;
>> To me "only actually 1 bit" makes it an implication that this is the
>> lowest bit (like in a bool represented in a 32-bit memory location).
>> I didn't think this was the case though, so unless I'm wrong, could
>> you clarify this a little?
> 
> There will be a single bit within the bottom 8 set (the 1 <<
> MSR_PLATFORM_ID[52:50]), despite this field being called "Platform Flags".

That's what I recalled. Could I talk you into
s/only actually 1 bit/only actually a single set bit/ or some such?
If so,
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan

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