RE: [PATCH v2 1/2] x86/mce/AMD: Redo use of SMCA MCA_DE{STAT,ADDR} registers

[Ghannam, Yazen]

> -----Original Message-----
> From: Borislav Petkov [mailto:bp@xxxxxxxxx]
> Sent: Tuesday, April 11, 2017 9:12 AM
> To: Ghannam, Yazen <Yazen.Ghannam@xxxxxxx>
> Cc: linux-edac@xxxxxxxxxxxxxxx; Tony Luck <tony.luck@xxxxxxxxx>;
> x86@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 1/2] x86/mce/AMD: Redo use of SMCA
> MCA_DE{STAT,ADDR} registers
> 
> On Tue, Apr 11, 2017 at 12:53:56PM +0000, Ghannam, Yazen wrote:
> > If we do as above then we can possibly log the same deferred error twice.
> 
> Why twice?
> 
> 	for_each_bank()
> 		log_error()
> 		|-> clear MSRs after logging
> 

So log_error() reads/clears MCA_STATUS, right? This won't affect MCA_DESTAT
on SMCA systems. So if we call log_error_smca() and unconditionally read
MCA_DESTAT, we will find the same deferred error that we logged in log_error().

Thanks,
Yazen