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

[Christoph Egger <Christoph.Egger@xxxxxxx>]

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


> 
> 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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