On 09/11/2014 05:10 AM, Christoffer Dall wrote: > On Mon, Sep 01, 2014 at 02:52:43PM +0200, Eric Auger wrote: >> In case the IRQ is forwarded, the VFIO platform IRQ handler does not >> need to disable the IRQ anymore. In that mode, when the handler completes > > add a comma after completes Hi Christoffer, ok > >> the IRQ is not deactivated but only its priority is lowered. >> >> Some other actor (typically a guest) is supposed to deactivate the IRQ, >> allowing at that time a new physical IRQ to hit. >> >> In virtualization use case, the physical IRQ is automatically completed >> by the interrupt controller when the guest completes the corresponding >> virtual IRQ. >> >> Signed-off-by: Eric Auger <eric.au...@linaro.org> >> --- >> drivers/vfio/platform/vfio_platform_irq.c | 7 ++++++- >> 1 file changed, 6 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/vfio/platform/vfio_platform_irq.c >> b/drivers/vfio/platform/vfio_platform_irq.c >> index 6768508..1f851b2 100644 >> --- a/drivers/vfio/platform/vfio_platform_irq.c >> +++ b/drivers/vfio/platform/vfio_platform_irq.c >> @@ -88,13 +88,18 @@ static irqreturn_t vfio_irq_handler(int irq, void >> *dev_id) >> struct vfio_platform_irq *irq_ctx = dev_id; >> unsigned long flags; >> int ret = IRQ_NONE; >> + struct irq_data *d; >> + bool is_forwarded; >> >> spin_lock_irqsave(&irq_ctx->lock, flags); >> >> if (!irq_ctx->masked) { >> ret = IRQ_HANDLED; >> + d = irq_get_irq_data(irq_ctx->hwirq); >> + is_forwarded = irqd_irq_forwarded(d); >> >> - if (irq_ctx->flags & VFIO_IRQ_INFO_AUTOMASKED) { >> + if (irq_ctx->flags & VFIO_IRQ_INFO_AUTOMASKED && >> + !is_forwarded) { >> disable_irq_nosync(irq_ctx->hwirq); >> irq_ctx->masked = true; >> } >> -- >> 1.9.1 >> > It makes sense that these needs to be all controlled in the kernel, but > I'm wondering if it would be cleaner / more correct to clear the > AUTOMASKED flag when the IRQ is forwarded and have vfio refuse setting > this flag as long as the irq is forwarded?
If I am not wrong, even if the user sets AUTOMASKED, this info never is exploited by the vfio platform driver. AUTOMASKED only is set internally to the driver, on init, for level sensitive IRQs. It seems to be the same on PCI (for INTx). I do not see anywhere the user flag curectly copied into a local storage. But I prefer to be careful ;-) If confirmed, although the flag value is exposed in the user API, the user set value never is exploited so this removes the need to check. the forwarded IRQ modality being fully dynamic currently, then I would need to update the irq_ctx->flags on each vfio_irq_handler call. I don't know if its better? Best Regards Eric > > -Christoffer > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html