Re: [PATCH] x86, MCE, AMD: save IA32_MCi_STATUS before machine_check_poll() resets it

Chen Yucong
2014-09-30T09:56:44Z

On Tue, 2014-09-30 at 09:25 +0200, Borislav Petkov wrote:
> > if (high & MASK_OVERFLOW_HI) {
> > rdmsrl(address, m.misc);
> > rdmsrl(MSR_IA32_MCx_STATUS(bank),
> m.status);
> > + if (m.status & MCI_STATUS_ADDRV)
> >
> + rdmsrl(MSR_IA32_MCx_ADDR(bank),
> m.addr);
> > m.bank = K8_MCE_THRESHOLD_BASE
> > + bank * NR_BLOCKS
> > + block;
> > mce_log(&m);
> > - return;
> > +
> > + wrmsrl(MSR_IA32_MCx_STATUS(bank), 0);
>
> No, machine_check_poll will clear it anyway and now you're adding a
> purely useless MSR write here which costs.
I just clear it to avoid that the mce_log() call logs the above
threshold event again in machine_check_poll().
>
> > + goto log_mcheck;
>
> Why goto? It will hit that machine_check_poll below even without
> it...
It is just used for scanning other banks for recording other valid
error information.

thx!
cyc