Re: [PATCH 4/9] x86/spec-ctrl: Improve all SPEC_CTRL_{ENTER,EXIT}_* comments

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 18/09/2023 11:59 am, Jan Beulich wrote:
> On 15.09.2023 17:00, Andrew Cooper wrote:
>> ... to better explain how they're used.
>>
>> Doing so highlights that SPEC_CTRL_EXIT_TO_XEN is missing a VERW flush for 
>> the
>> corner case when e.g. an NMI hits late in an exit-to-guest path.
>>
>> Leave a TODO, which will be addressed in subsequent patches which arrange for
>> DO_COND_VERW to be safe within SPEC_CTRL_EXIT_TO_XEN.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> Two nits though:
>
>> @@ -233,7 +236,11 @@
>>          X86_FEATURE_SC_MSR_PV
>>  .endm
>>  
>> -/* Use in interrupt/exception context.  May interrupt Xen or PV context. */
>> +/*
>> + * Used after an exception or maskable interrupt, hitting Xen or PV context.
>> + * There will either be a guest speculation context, or (baring fatal
> Isn't this "barring"?
>
>> @@ -260,7 +270,13 @@
>>  .endm
>>  
>>  /*
>> - * Use in IST interrupt/exception context.  May interrupt Xen or PV context.
>> + * Used after an IST entry hitting Xen or PV context.  Special care is 
>> needed,
>> + * because when hitting Xen context, there may not a well-formed speculation
> Missing "be"?

Both fixed, thanks.

~Andrew