[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v7 08/12] xen/arm: rename GIC_IRQ_GUEST_PENDING to GIC_IRQ_GUEST_QUEUED
On Tue, 2014-04-08 at 16:12 +0100, Stefano Stabellini wrote: > Rename GIC_IRQ_GUEST_PENDING to GIC_IRQ_GUEST_QUEUED and clarify its > meaning in xen/include/asm-arm/domain.h. Thanks. > diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h > index 2d94d59..f96dc12 100644 > --- a/xen/include/asm-arm/domain.h > +++ b/xen/include/asm-arm/domain.h > @@ -27,7 +27,8 @@ struct pending_irq > * whether an irq added to an LR register is PENDING or ACTIVE, the > * following states are just an approximation. > * > - * GIC_IRQ_GUEST_PENDING: the irq is asserted > + * GIC_IRQ_GUEST_QUEUED: the irq is asserted and queued for > + * injection into the guests LRs. guest's > * > * GIC_IRQ_GUEST_VISIBLE: the irq has been added to an LR register, > * therefore the guest is aware of it. From the guest point of view > @@ -35,12 +36,12 @@ struct pending_irq > * or active (after acking the irq). > * > * In order for the state machine to be fully accurate, for level > - * interrupts, we should keep the GIC_IRQ_GUEST_PENDING state until > + * interrupts, we should keep the GIC_IRQ_GUEST_QUEUED state until > * the guest deactivates the irq. However because we are not sure > - * when that happens, we simply remove the GIC_IRQ_GUEST_PENDING > + * when that happens, we simply remove the GIC_IRQ_GUEST_QUEUED > * state when we add the irq to an LR register. We add it back when > * we receive another interrupt notification. This paragraph was essentially clarifying the mismatch between the name PENDING and the actual behaviour. It doesn't seem to make much sense for a bit named QUEUED. In particular "we should keep the QUEUE state until the guest deactivates the IRQ" doesn't seem logical, so the rest doesn't follow as a workaround for it. How about: * In order for the state machine to be fully accurate, for level * interrupts, we should keep the interrupt's pending state until * the guest deactivates the irq. However because we are not sure * when that happens, we instead track whether there is an interrupt * queued using GIC_IRQ_GUEST_QUEUED * state when we add the irq to an LR register. We add it back when * we receive another interrupt notification. (needs rewrapping). Still doesn't sound quite right to me, but you understand what is going on better than me so I hope you can fix it ;-) > - * Therefore it is possible to set GIC_IRQ_GUEST_PENDING while the > + * Therefore it is possible to set GIC_IRQ_GUEST_QUEUED while the > * irq is GIC_IRQ_GUEST_VISIBLE. We could also change the state of > * the guest irq in the LR register from active to active and > * pending, but for simplicity we simply inject a second irq after Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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