On Wed, 2023-03-22 at 17:42 +0100, Cornelia Huck wrote: > On Wed, Mar 22 2023, "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > On Wed, Mar 22, 2023 at 05:10:31PM +0300, Viktor Prutyanov wrote: > > > According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature > > > indicates that the driver passes extra data along with the queue > > > notifications. > > > > > > In a split queue case, the extra data is 16-bit available index. > > > In a > > > packed queue case, the extra data is 1-bit wrap counter and 15- > > > bit > > > available index. > > > > > > Add support for this feature for MMIO, channel I/O and modern PCI > > > transports. > > > > > > Signed-off-by: Viktor Prutyanov <viktor@xxxxxxxxxx> > > > --- > > > v4: remove VP_NOTIFY macro and legacy PCI support, add > > > virtio_ccw_kvm_notify_with_data to virtio_ccw > > > v3: support feature in virtio_ccw, remove VM_NOTIFY, use > > > avail_idx_shadow, > > > remove byte swap, rename to vring_notification_data > > > v2: reject the feature in virtio_ccw, replace __le32 with u32 > > > > > > Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system- > > > s390x > > > (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device, > > > virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio- > > > net-pci) > > > to make sure nothing is broken. > > > Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V > > > Linux > > > and my hardware implementation of virtio-rng. > > > > what did you test? virtio pci? mmio? guessing not ccw... > > > > Cornelia could you hack up something to quickly test ccw? > > Hm, I'm not entirely sure how notification data is supposed to be > used > in real life -- Viktor, what is your virtio-rng implementation doing; > can this be hacked into all transports? > > (Also, if the other ccw folks have something handy, please speak up > :) > (Sorry for delay, caught the illness going through our house before I had a chance to look at this.) I applied v6 of this patch and hacked to QEMU to enable VIRTIO_F_NOTIFICATION_DATA for virtio-blk, and have the -ccw code ignore the additional data that then comes along the way. Not surprisingly, things behave fine once I accommodate the new payload. To Cornelia's point of how it should be used in real life... I didn't go beyond using this info as a "debugging aid" here, based on time constraints. But at least it looks reasonable. Eric
