Re: [Xen-devel] [PATCH 2/5] Xen/MCE: vMCE injection

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

Christoph Egger wrote:
> On 09/19/12 10:03, Liu, Jinsong wrote:
> 
>> Xen/MCE: vMCE injection
>> 
>> In our test for win8 guest mce, we find a bug that no matter what
>> SRAO/SRAR error xen inject to win8 guest, it always reboot.
>> 
>> The root cause is, current Xen vMCE logic inject vMCE# only to
>> vcpu0, this is not correct for Intel MCE (Under Intel arch, h/w
>> generate MCE# to all CPUs). 
>> 
>> This patch fix vMCE injection bug, injecting vMCE# to all vcpus.
> 
> 
> This breaks the AMD way. The AMD way is to only inject it to vcpu0.
> I suggest to add a flag argument to inject_vmce() that says whether
> to inject to all vcpus or just vcpu0.
> Then set/clear that flag from the caller side depending on whether you
> run on Intel or AMD.
> 
> Christoph
> 

No, it didn't breaks AMD since it only called by intel_memerr_dhandler().

Thanks,
Jinsong

> 
>> 
>> Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
>> 
>> diff -r 133664c6bfb4 xen/arch/x86/cpu/mcheck/vmce.c
>> --- a/xen/arch/x86/cpu/mcheck/vmce.c Tue Sep 18 22:39:11 2012 +0800
>> +++ b/xen/arch/x86/cpu/mcheck/vmce.c Tue Sep 18 23:46:38 2012 +0800
>> @@ -340,48 +340,27 @@ 
>> 
>>  int inject_vmce(struct domain *d)
>>  {
>> -    int cpu = smp_processor_id();
>> +    struct vcpu *v;
>> 
>> -    /* PV guest and HVM guest have different vMCE# injection
>> methods. */ 
>> -    if ( !test_and_set_bool(d->vcpu[0]->mce_pending) )
>> +    /* inject vMCE to all vcpus */
>> +    for_each_vcpu(d, v)
>>      {
>> -        if ( d->is_hvm )
>> +        if ( !test_and_set_bool(v->mce_pending) && +           
>> ((d->is_hvm) || +                guest_has_trap_callback(d,
>> v->vcpu_id, TRAP_machine_check)) )          { 
>> -            mce_printk(MCE_VERBOSE, "MCE: inject vMCE to HVM DOM
>> %d\n", 
>> -                       d->domain_id);
>> -            vcpu_kick(d->vcpu[0]);
>> +            mce_printk(MCE_VERBOSE, "MCE: inject vMCE to dom%d
>> vcpu%d\n", +                       d->domain_id, v->vcpu_id);
>> +            vcpu_kick(v);
>>          }
>>          else
>>          {
>> -            mce_printk(MCE_VERBOSE, "MCE: inject vMCE to PV
>> DOM%d\n", 
>> -                       d->domain_id);
>> -            if ( guest_has_trap_callback(d, 0, TRAP_machine_check) )
>> -            {
>> -                cpumask_copy(d->vcpu[0]->cpu_affinity_tmp,
>> -                             d->vcpu[0]->cpu_affinity);
>> -                mce_printk(MCE_VERBOSE, "MCE: CPU%d set affinity,
>> old %d\n", 
>> -                           cpu, d->vcpu[0]->processor);
>> -                vcpu_set_affinity(d->vcpu[0], cpumask_of(cpu));
>> -                vcpu_kick(d->vcpu[0]);
>> -            }
>> -            else
>> -            {
>> -                mce_printk(MCE_VERBOSE,
>> -                           "MCE: Kill PV guest with No MCE
>> handler\n"); 
>> -                domain_crash(d);
>> -            }
>> +            mce_printk(MCE_QUIET, "Fail to inject vMCE to dom%d
>> vcpu%d\n", +                       d->domain_id, v->vcpu_id);
>> +            return -1;
>>          }
>>      }
>> -    else
>> -    {
>> -        /* new vMCE comes while first one has not been injected yet,
>> -         * in this case, inject fail. [We can't lose this vMCE for
>> -         * the mce node's consistency].
>> -         */
>> -        mce_printk(MCE_QUIET, "There's a pending vMCE waiting to be
>> injected " 
>> -                   " to this DOM%d!\n", d->domain_id);
>> -        return -1;
>> -    }
>> +
>>      return 0;
>>  }


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