Re: [PATCH] Add function for clearing the requested VCPUs' mce registers.

[Huang Ying <ying.huang@intel.com>]

On Thu, 2010-11-25 at 13:30 +0800, Jin Dongming wrote:
> Hi, Huang-san
> 
> (2010/11/25 10:27), Huang Ying wrote:
> > Hi, Dongming,
> > 
> > On Thu, 2010-11-25 at 09:14 +0800, Jin Dongming wrote:
> >> In some case of mce test, the injected data can be remained
> >> in the registers and ca affect to the result of following test cases.
> >> So add codes for clearing mce registers of given VCPU.
> >>
> >> mce registers of give VCPU could be cleared from kernel by calling
> >> the function in this patch.  What need to be paid attention is that
> >> the status and mcg_status of mce must be set with 0. If not, mce
> >> registers will not be cleared.
> > 
> > Why do you need this? To use "mce=3" in guest Linux MCE testing?
> When I set fake_panic==1 on Guest OS and tested mce via qemu-monitor,
> I got the wrong result sometimes. The reason why I got the wrong result
> was that mce registers were not cleared. So I made this patch.

This can be done in QEMU via KVM_SET_MSRS too.
 
> > If it is, why not use full reboot? MCE registers are not cleared in real
> > machine too. And it is not so pain to reboot the guest.
> Though we know that mce registers could be cleared by rebooting the Guest
> Machine and the reboot of Guest Machine could save much more time than
> the reboot of Host Machine, it is still slower than setting
> fake_panic==1 to mce test.

Best Regards,
Huang Ying