Re: [Xen-devel] map_domain_emuirq_pirq() imbalance with unmap_domain_pirq_emuirq()?

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 13.12.11 at 18:16, Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> 
>>> wrote:
> --- a/xen/arch/x86/physdev.c
> +++ b/xen/arch/x86/physdev.c
> @@ -216,14 +216,16 @@ int physdev_unmap_pirq(domid_t domid, int pirq)
>      if ( ret )
>          return ret;
>  
> -    if ( is_hvm_domain(d) )
> +    if ( is_hvm_domain(d) && domain_pirq_to_emuirq(d, pirq) != IRQ_UNBOUND)
>      {
>          spin_lock(&d->event_lock);
>          ret = unmap_domain_pirq_emuirq(d, pirq);
>          spin_unlock(&d->event_lock);
> -        if ( domid == DOMID_SELF || ret )
> +        if ( ret )
>              goto free_domain;
>      }
> +    if ( domid == DOMID_SELF )
> +        goto free_domain;
>  
>      ret = -EPERM;
>      if ( !IS_PRIV_FOR(current->domain, d) )

I think this is the correct change (untested so far):

@@ -228,7 +228,8 @@ static int physdev_unmap_pirq(struct phy
     if ( is_hvm_domain(d) )
     {
         spin_lock(&d->event_lock);
-        ret = unmap_domain_pirq_emuirq(d, pirq);
+        if ( domain_pirq_to_emuirq(d, pirq) != IRQ_UNBOUND )
+            ret = unmap_domain_pirq_emuirq(d, pirq);
         spin_unlock(&d->event_lock);
         if ( unmap->domid == DOMID_SELF || ret )
             goto free_domain;

i.e. do the lookup with the lock held (and taking advantage of 'ret'
being zero when reaching the enclosing if()).

Jan


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