Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Thu, Nov 17, 2016 at 04:04:26AM -0500, Paolo Bonzini wrote: > > > > > > /* > > > > > > * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but > > > > > > * windows drivers included in virtio-win 1.8.0 (circa 2015) > > > > > > * for Windows 8.1 only are incorrectly polling this bit

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Wed, Nov 16, 2016 at 10:15:25PM +0200, Michael S. Tsirkin wrote: > On Wed, Nov 16, 2016 at 07:05:51PM +0100, Paolo Bonzini wrote: > > @@ -1356,6 +1349,17 @@ bool virtio_should_notify(VirtIODevice *vdev, > > VirtQueue *vq) > > return !v || vring_need_event(vring_get_used_event(vq), new,

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

> > > > > /* > > > > > * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but > > > > > * windows drivers included in virtio-win 1.8.0 (circa 2015) > > > > > * for Windows 8.1 only are incorrectly polling this bit during > > > > > shutdown > > > > > > > > >

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Wed, Nov 16, 2016 at 04:05:31PM -0500, Paolo Bonzini wrote: > > > - Original Message - > > From: "Michael S. Tsirkin" > > To: "Paolo Bonzini" > > Cc: qemu-devel@nongnu.org, "alex williamson" , > >

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

- Original Message - > From: "Michael S. Tsirkin" > To: "Paolo Bonzini" > Cc: qemu-devel@nongnu.org, "alex williamson" , > borntrae...@de.ibm.com, fel...@nutanix.com > Sent: Wednesday, November 16, 2016 9:39:24 PM >

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

> > +void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) > > +{ > > +if (!virtio_should_notify(vdev, vq)) { > > +return; > > +} > > + > > +trace_virtio_notify_irqfd(vdev, vq); > > +virtio_set_isr(vq->vdev, 0x1); > > So here, I think we need a comment with parts of

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Wed, Nov 16, 2016 at 07:05:51PM +0100, Paolo Bonzini wrote: > Dataplane has been omitting forever the step of setting ISR when > an interrupt is raised. This caused little breakage, because the > specification actually says that ISR may not be updated in MSI mode. > > Some versions of the

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Wed, Nov 16, 2016 at 03:38:11PM -0500, Paolo Bonzini wrote: > > > +void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) > > > +{ > > > +if (!virtio_should_notify(vdev, vq)) { > > > +return; > > > +} > > > + > > > +trace_virtio_notify_irqfd(vdev, vq); > > > +

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, 15 Nov 2016 21:17:56 +0200 "Michael S. Tsirkin" wrote: > On Tue, Nov 15, 2016 at 11:21:55AM -0700, Alex Williamson wrote: > > On Tue, 15 Nov 2016 19:58:52 +0200 > > "Michael S. Tsirkin" wrote: > > > > > On Tue, Nov 15, 2016 at 10:48:15AM -0700, Alex

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, Nov 15, 2016 at 11:21:55AM -0700, Alex Williamson wrote: > On Tue, 15 Nov 2016 19:58:52 +0200 > "Michael S. Tsirkin" wrote: > > > On Tue, Nov 15, 2016 at 10:48:15AM -0700, Alex Williamson wrote: > > > On Tue, 15 Nov 2016 19:38:30 +0200 > > > "Michael S. Tsirkin"

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, 15 Nov 2016 19:58:52 +0200 "Michael S. Tsirkin" wrote: > On Tue, Nov 15, 2016 at 10:48:15AM -0700, Alex Williamson wrote: > > On Tue, 15 Nov 2016 19:38:30 +0200 > > "Michael S. Tsirkin" wrote: > > > > > On Tue, Nov 15, 2016 at 05:22:49PM +0100, Paolo

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, Nov 15, 2016 at 10:48:15AM -0700, Alex Williamson wrote: > On Tue, 15 Nov 2016 19:38:30 +0200 > "Michael S. Tsirkin" wrote: > > > On Tue, Nov 15, 2016 at 05:22:49PM +0100, Paolo Bonzini wrote: > > > > > > > > > On 15/11/2016 16:44, Michael S. Tsirkin wrote: > > > >

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, 15 Nov 2016 19:38:30 +0200 "Michael S. Tsirkin" wrote: > On Tue, Nov 15, 2016 at 05:22:49PM +0100, Paolo Bonzini wrote: > > > > > > On 15/11/2016 16:44, Michael S. Tsirkin wrote: > > > True. We could drop it from non-data plane, it's just that we never had > > > a

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, Nov 15, 2016 at 05:22:49PM +0100, Paolo Bonzini wrote: > > > On 15/11/2016 16:44, Michael S. Tsirkin wrote: > > True. We could drop it from non-data plane, it's just that we never had > > a reason to. vhost in kernel does not set ISR in MSI mode, either. > > Yeah, I suspected that. But

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On 15/11/2016 16:44, Michael S. Tsirkin wrote: > True. We could drop it from non-data plane, it's just that we never had > a reason to. vhost in kernel does not set ISR in MSI mode, either. Yeah, I suspected that. But dropping it from non-dataplane would break Windows hibernation and

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, Nov 15, 2016 at 04:28:37PM +0100, Paolo Bonzini wrote: > > > On 15/11/2016 16:26, Michael S. Tsirkin wrote: > > On Tue, Nov 15, 2016 at 02:46:29PM +0100, Paolo Bonzini wrote: > >> Dataplane has been omitting forever the step of setting ISR when an > >> interrupt is raised. This causes

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On 15/11/2016 16:26, Michael S. Tsirkin wrote: > On Tue, Nov 15, 2016 at 02:46:29PM +0100, Paolo Bonzini wrote: >> Dataplane has been omitting forever the step of setting ISR when an >> interrupt is raised. This causes surprisingly little breakage, >> because most polling-mode drivers look at

Re: [Qemu-devel] [PATCH 3/3] virtio: set ISR on dataplane notifications

On Tue, Nov 15, 2016 at 02:46:29PM +0100, Paolo Bonzini wrote: > Dataplane has been omitting forever the step of setting ISR when an > interrupt is raised. This causes surprisingly little breakage, > because most polling-mode drivers look at the used ring's index field > rather than the ISR