qemu/hw/scsi
Stefano Garzarella 4daa5054c5 vhost: enable vrings in vhost_dev_start() for vhost-user devices
Commit 02b61f38d3 ("hw/virtio: incorporate backend features in features")
properly negotiates VHOST_USER_F_PROTOCOL_FEATURES with the vhost-user
backend, but we forgot to enable vrings as specified in
docs/interop/vhost-user.rst:

    If ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been negotiated, the
    ring starts directly in the enabled state.

    If ``VHOST_USER_F_PROTOCOL_FEATURES`` has been negotiated, the ring is
    initialized in a disabled state and is enabled by
    ``VHOST_USER_SET_VRING_ENABLE`` with parameter 1.

Some vhost-user front-ends already did this by calling
vhost_ops.vhost_set_vring_enable() directly:
- backends/cryptodev-vhost.c
- hw/net/virtio-net.c
- hw/virtio/vhost-user-gpio.c

But most didn't do that, so we would leave the vrings disabled and some
backends would not work. We observed this issue with the rust version of
virtiofsd [1], which uses the event loop [2] provided by the
vhost-user-backend crate where requests are not processed if vring is
not enabled.

Let's fix this issue by enabling the vrings in vhost_dev_start() for
vhost-user front-ends that don't already do this directly. Same thing
also in vhost_dev_stop() where we disable vrings.

[1] https://gitlab.com/virtio-fs/virtiofsd
[2] https://github.com/rust-vmm/vhost/blob/240fc2966/crates/vhost-user-backend/src/event_loop.rs#L217

Fixes: 02b61f38d3 ("hw/virtio: incorporate backend features in features")
Reported-by: German Maglione <gmaglione@redhat.com>
Tested-by: German Maglione <gmaglione@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221123131630.52020-1-sgarzare@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-12-01 02:30:04 -05:00
..
emulation.c scsi-generic: avoid invalid access to struct when emulating block limits 2018-11-06 21:35:06 +01:00
esp-pci.c pci: Let pci_dma_rw() take MemTxAttrs argument 2021-12-31 01:05:23 +01:00
esp.c Fix several typos in documentation (found by codespell) 2022-11-11 09:39:25 +01:00
Kconfig build: move vhost-scsi configuration to Kconfig 2022-05-07 07:46:58 +02:00
lsi53c895a.c scsi: Use device_cold_reset() and bus_cold_reset() 2022-10-18 13:58:04 +02:00
megasas.c scsi: Use device_cold_reset() and bus_cold_reset() 2022-10-18 13:58:04 +02:00
meson.build meson: convert hw/scsi 2020-08-21 06:30:28 -04:00
mfi.h Fix 'writeable' typos 2022-06-08 19:38:47 +01:00
mpi.h hw: Add support for LSI SAS1068 (mptsas) device 2016-02-09 15:45:26 +01:00
mptconfig.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
mptendian.c nomaintainer: Fix Lesser GPL version number 2020-11-15 17:04:40 +01:00
mptsas.c scsi: Use device_cold_reset() and bus_cold_reset() 2022-10-18 13:58:04 +02:00
mptsas.h mptsas: Remove unused MPTSASState 'pending' field (CVE-2021-3392) 2021-04-19 15:48:12 +01:00
scsi-bus.c virtio-scsi: Send "REPORTED LUNS CHANGED" sense data upon disk hotplug events 2022-10-13 23:38:33 +02:00
scsi-disk.c scsi-disk: support setting CD-ROM block size via device options 2022-10-10 09:23:16 +02:00
scsi-generic.c scsi: Add buf_len parameter to scsi_req_new() 2022-09-01 07:42:37 +02:00
spapr_vscsi.c scsi: Use device_cold_reset() and bus_cold_reset() 2022-10-18 13:58:04 +02:00
srp.h spapr-vscsi: add task management 2013-09-12 08:46:21 +02:00
trace-events scsi-disk: allow MODE SELECT block descriptor to set the block size 2022-07-13 16:58:58 +02:00
trace.h trace: switch position of headers to what Meson requires 2020-08-21 06:18:24 -04:00
vhost-scsi-common.c vhost: enable vrings in vhost_dev_start() for vhost-user devices 2022-12-01 02:30:04 -05:00
vhost-scsi.c vhost: mask VIRTIO_F_RING_RESET for vhost and vhost-user devices 2022-11-22 05:19:00 -05:00
vhost-user-scsi.c vhost: mask VIRTIO_F_RING_RESET for vhost and vhost-user devices 2022-11-22 05:19:00 -05:00
viosrp.h hw/scsi/spapr_vscsi: Do not mix SRP IU size with DMA buffer size 2020-03-17 15:08:50 +11:00
virtio-scsi-dataplane.c virtio-scsi: fix race in virtio_scsi_dataplane_start() 2022-08-17 07:07:37 -04:00
virtio-scsi.c scsi: Use device_cold_reset() and bus_cold_reset() 2022-10-18 13:58:04 +02:00
vmw_pvscsi.c hw/scsi/vmw_pvscsi.c: Use device_cold_reset() to reset SCSI devices 2022-10-18 13:58:04 +02:00
vmw_pvscsi.h scsi: VMWare PVSCSI paravirtual device implementation 2013-04-19 10:44:17 +02:00