Re: [Xen-devel] [PATCH v9 04/12] xen/arm: support HW interrupts, do not request maintenance_interrupts

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi Stefano,

On 06/10/2014 03:07 PM, Stefano Stabellini wrote:
> +static void gic_update_one_lr(struct vcpu *v, int i)
> +{
> +    struct pending_irq *p;
> +    uint32_t lr;
> +    int irq;
> +
> +    ASSERT(spin_is_locked(&v->arch.vgic.lock));
> +
> +    lr = GICH[GICH_LR + i];
> +    if ( !(lr & (GICH_LR_PENDING|GICH_LR_ACTIVE)) )
> +    {
> +        GICH[GICH_LR + i] = 0;
> +        clear_bit(i, &this_cpu(lr_mask));
> +
> +        irq = (lr >> GICH_LR_VIRTUAL_SHIFT) & GICH_LR_VIRTUAL_MASK;
> +        p = irq_to_pending(v, irq);
> +        if ( p->desc != NULL )
> +            p->desc->status &= ~IRQ_INPROGRESS;

Reading again this patch... shouldn't we take the desc->lock here?

It's possible to receive the same interrupt while we update the LRs
(depending how the IRQ has been physically route) so we may overwrite
the IRQ_INPROGRESS bit.

Regards,

-- 
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel