Re: [PATCH] x86/MSI: fix guest unmasking when handling IRQ via event channel

[David Vrabel <david.vrabel@citrix.com>]

On 08/07/15 09:56, Jan Beulich wrote:
> Rather than assuming only PV guests need special treatment (and
> dealing with that directly when an IRQ gets set up), keep all guest MSI
> IRQs masked until either the (HVM) guest unmasks them via vMSI or the
> (PV, PVHVM, or PVH) guest sets up an event channel for it.
> 
> To not further clutter the common evtchn_bind_pirq() with x86-specific
> code, introduce an arch_evtchn_bind_pirq() hook instead.

Can you describe the symptoms of the bug being fixed here?

> --- a/xen/include/asm-arm/irq.h
> +++ b/xen/include/asm-arm/irq.h
> @@ -47,6 +47,8 @@ int release_guest_irq(struct domain *d, 
>  
>  void arch_move_irqs(struct vcpu *v);
>  
> +#define arch_evtchn_bind_pirq(d, pirq) ((void)((d) + (pirq)))

Would this be better as a inline function?

> +
>  /* Set IRQ type for an SPI */
>  int irq_set_spi_type(unsigned int spi, unsigned int type);
>  
> --- a/xen/include/xen/irq.h
> +++ b/xen/include/xen/irq.h
> @@ -172,4 +172,8 @@ unsigned int set_desc_affinity(struct ir
>  unsigned int arch_hwdom_irqs(domid_t);
>  #endif
>  
> +#ifndef arch_evtchn_bind_pirq
> +void arch_evtchn_bind_pirq(struct domain *, int pirq);

... moving this into xen/include/asm-x86/irq.h

David