Re: [BUGFIX] MCE: Fix bug of IA32_MCG_STATUS after system reset

[Marcelo Tosatti <mtosatti@redhat.com>]

On Wed, Jan 06, 2010 at 04:17:42PM +0800, Huang Ying wrote:
> On Wed, 2010-01-06 at 16:03 +0800, Avi Kivity wrote:
> > On 01/06/2010 09:05 AM, Huang Ying wrote:
> > > @@ -1015,6 +1015,7 @@ void kvm_arch_load_regs(CPUState *env)
> > >>>    #endif
> > >>>        set_msr_entry(&msrs[n++], MSR_KVM_SYSTEM_TIME,  env->system_time_msr);
> > >>>        set_msr_entry(&msrs[n++], MSR_KVM_WALL_CLOCK,  env->wall_clock_msr);
> > >>> +    set_msr_entry(&msrs[n++], MSR_MCG_STATUS, 0);
> > >>>
> > >>>
> > >>>        
> > >> Not sure why you reset this in kvm_arch_load_regs().  Shouldn't this be
> > >> in the cpu reset code?
> > >>      
> > > I found kvm_arch_load_regs() is called by kvm_arch_cpu_reset(), which is
> > > called by qemu_kvm_system_reset(). It is not in cpu reset path?
> > >    
> > 
> > It is, but it is also called from many other places, which could cause 
> > this msr to be zeroed.
> > 
> > A better solution is to allocate it a field in CPUState, load and save 
> > it in kvm_arch_*_regs, and zero it during reset.
> 
> Yes. You are right. I will fix this.

BTW, the MCE MSRs are not being migrated. Perhaps you'd like to fix that
while at it.