search for: ssch

...tus(struct virtio_device *vdev, u8 status) ccw->cmd_code = CCW_CMD_WRITE_STATUS; ccw->flags = 0; ccw->count = sizeof(status); - ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status; + ccw->cda = (__u32)virt_to_phys(&vcdev->dma_area->status); /* We use ssch for setting the status which is a serializing * instruction that guarantees the memory writes have * completed before ssch. @@ -1274,7 +1276,7 @@ static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev) ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV; ccw->flags = 0; ccw-&g...

...tus(struct virtio_device *vdev, u8 status) ccw->cmd_code = CCW_CMD_WRITE_STATUS; ccw->flags = 0; ccw->count = sizeof(status); - ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status; + ccw->cda = (__u32)virt_to_phys(&vcdev->dma_area->status); /* We use ssch for setting the status which is a serializing * instruction that guarantees the memory writes have * completed before ssch. @@ -1274,7 +1276,7 @@ static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev) ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV; ccw->flags = 0; ccw-&g...

On Thu, Oct 23, 2014 at 02:28:08PM +0200, Cornelia Huck wrote: > On Wed, 22 Oct 2014 21:44:44 +0300 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > set FEATURES_OK as per virtio 1.0 spec > > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > include/uapi/linux/virtio_config.h | 2 ++ > >

On Thu, Oct 23, 2014 at 02:28:08PM +0200, Cornelia Huck wrote: > On Wed, 22 Oct 2014 21:44:44 +0300 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > set FEATURES_OK as per virtio 1.0 spec > > > > Signed-off-by: Michael S. Tsirkin <mst at redhat.com> > > --- > > include/uapi/linux/virtio_config.h | 2 ++ > >

On Wed, Mar 04, 2015 at 04:44:54PM +1030, Rusty Russell wrote: > "Michael S. Tsirkin" <mst at redhat.com> writes: > > On Mon, Mar 02, 2015 at 10:37:26AM +1030, Rusty Russell wrote: > >> Thomas Huth <thuth at linux.vnet.ibm.com> writes: > >> > On Thu, 26 Feb 2015 11:50:42 +1030 > >> > Rusty Russell <rusty at rustcorp.com.au>

On Wed, Mar 04, 2015 at 04:44:54PM +1030, Rusty Russell wrote: > "Michael S. Tsirkin" <mst at redhat.com> writes: > > On Mon, Mar 02, 2015 at 10:37:26AM +1030, Rusty Russell wrote: > >> Thomas Huth <thuth at linux.vnet.ibm.com> writes: > >> > On Thu, 26 Feb 2015 11:50:42 +1030 > >> > Rusty Russell <rusty at rustcorp.com.au>

...ys sleeps > because it's interrupt driven. (...) > So I suspect > http://mid.gmane.org/1424874878-17155-1-git-send-email-mst at redhat.com > is better. > > What do you think? I'd prefer to fix this as well. While the I/O request completes instantly on current qemu (the ssch backend handles the start function immediately, not asynchronously as on real hardware), this (a) is an implementation detail that may change and (b) doesn't account for the need to deliver the interrupt to the guest - which might take non-zero time.

...ys sleeps > because it's interrupt driven. (...) > So I suspect > http://mid.gmane.org/1424874878-17155-1-git-send-email-mst at redhat.com > is better. > > What do you think? I'd prefer to fix this as well. While the I/O request completes instantly on current qemu (the ssch backend handles the start function immediately, not asynchronously as on real hardware), this (a) is an implementation detail that may change and (b) doesn't account for the need to deliver the interrupt to the guest - which might take non-zero time.

...the Linux guest driver uses a simple wrapper that makes it appear synchronous). This means, for example, that every status update now involves two channel programs instead of one, and that reading e.g. the status sysfs attribute in Linux now triggers channel I/O, which means several exits (at least ssch, interrupt injection, tsch; probably more depending on what the guest does)...