Re: [PATCH v3] x86/amd: Address AMD erratum #1485

["Roger Pau Monné" <roger.pau@citrix.com>]

On Tue, Oct 17, 2023 at 08:50:45AM +0100, Andrew Cooper wrote:
> On 17/10/2023 8:44 am, Jan Beulich wrote:
> > On 13.10.2023 17:38, Alejandro Vallejo wrote:
> >> Fix adapted off Linux's mailing list:
> >>   https://lore.kernel.org/lkml/D99589F4-BC5D-430B-87B2-72C20370CF57@exactcode.com/T/#u
> > Why reference the bug report when there's a proper commit (f454b18e07f5) now?
> > Plus in any event a short summary of the erratum would help if put right here
> > (without needing to look up any documents or follow any links).
> 
> That is not public information yet.  The erratum number alone is the
> best we can do at this juncture.
> >> --- a/xen/arch/x86/cpu/amd.c
> >> +++ b/xen/arch/x86/cpu/amd.c
> >> @@ -1004,6 +1004,28 @@ static void cf_check zen2_disable_c6(void *arg)
> >>  	wrmsrl(MSR_AMD_CSTATE_CFG, val & mask);
> >>  }
> >>  
> >> +static void amd_check_erratum_1485(void)
> >> +{
> >> +	uint64_t val, chickenbit = (1 << 5);
> > Linux gives the bit a name. Any reason you don't?
> 
> There are multiple different names depending on where you look, and none
> are particularly relevant here.

Could we make chickenbit const static?

I would also use ULL just to be on the safe side, because we then copy
this for a different bit and it explodes.

(not strong requirements, but if a resend is needed it would be nice
to have).

Thanks, Roger.