From 4daa5054c599c8aec70f1264a01341a15921c145 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Wed, 30 Nov 2022 11:24:36 +0000 Subject: [PATCH] vhost: enable vrings in vhost_dev_start() for vhost-user devices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Tested-by: German Maglione Signed-off-by: Stefano Garzarella Acked-by: Raphael Norwitz Message-Id: <20221123131630.52020-1-sgarzare@redhat.com> Signed-off-by: Alex Bennée Reviewed-by: Michael S. Tsirkin Message-Id: <20221130112439.2527228-3-alex.bennee@linaro.org> Signed-off-by: Michael S. Tsirkin --- backends/cryptodev-vhost.c | 4 ++-- backends/vhost-user.c | 4 ++-- hw/block/vhost-user-blk.c | 4 ++-- hw/net/vhost_net.c | 8 +++---- hw/scsi/vhost-scsi-common.c | 4 ++-- hw/virtio/trace-events | 4 ++-- hw/virtio/vhost-user-fs.c | 4 ++-- hw/virtio/vhost-user-gpio.c | 4 ++-- hw/virtio/vhost-user-i2c.c | 4 ++-- hw/virtio/vhost-user-rng.c | 4 ++-- hw/virtio/vhost-vsock-common.c | 4 ++-- hw/virtio/vhost.c | 44 ++++++++++++++++++++++++++++++---- include/hw/virtio/vhost.h | 6 +++-- 13 files changed, 67 insertions(+), 31 deletions(-) diff --git a/backends/cryptodev-vhost.c b/backends/cryptodev-vhost.c index bc13e466b4..572f87b3be 100644 --- a/backends/cryptodev-vhost.c +++ b/backends/cryptodev-vhost.c @@ -94,7 +94,7 @@ cryptodev_vhost_start_one(CryptoDevBackendVhost *crypto, goto fail_notifiers; } - r = vhost_dev_start(&crypto->dev, dev); + r = vhost_dev_start(&crypto->dev, dev, false); if (r < 0) { goto fail_start; } @@ -111,7 +111,7 @@ static void cryptodev_vhost_stop_one(CryptoDevBackendVhost *crypto, VirtIODevice *dev) { - vhost_dev_stop(&crypto->dev, dev); + vhost_dev_stop(&crypto->dev, dev, false); vhost_dev_disable_notifiers(&crypto->dev, dev); } diff --git a/backends/vhost-user.c b/backends/vhost-user.c index 5dedb2d987..7bfcaef976 100644 --- a/backends/vhost-user.c +++ b/backends/vhost-user.c @@ -85,7 +85,7 @@ vhost_user_backend_start(VhostUserBackend *b) } b->dev.acked_features = b->vdev->guest_features; - ret = vhost_dev_start(&b->dev, b->vdev); + ret = vhost_dev_start(&b->dev, b->vdev, true); if (ret < 0) { error_report("Error start vhost dev"); goto err_guest_notifiers; @@ -120,7 +120,7 @@ vhost_user_backend_stop(VhostUserBackend *b) return; } - vhost_dev_stop(&b->dev, b->vdev); + vhost_dev_stop(&b->dev, b->vdev, true); if (k->set_guest_notifiers) { ret = k->set_guest_notifiers(qbus->parent, diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c index 0d5190accf..1177064631 100644 --- a/hw/block/vhost-user-blk.c +++ b/hw/block/vhost-user-blk.c @@ -178,7 +178,7 @@ static int vhost_user_blk_start(VirtIODevice *vdev, Error **errp) } s->dev.vq_index_end = s->dev.nvqs; - ret = vhost_dev_start(&s->dev, vdev); + ret = vhost_dev_start(&s->dev, vdev, true); if (ret < 0) { error_setg_errno(errp, -ret, "Error starting vhost"); goto err_guest_notifiers; @@ -213,7 +213,7 @@ static void vhost_user_blk_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&s->dev, vdev); + vhost_dev_stop(&s->dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, s->dev.nvqs, false); if (ret < 0) { diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c index 26e4930676..043058ff43 100644 --- a/hw/net/vhost_net.c +++ b/hw/net/vhost_net.c @@ -259,7 +259,7 @@ static int vhost_net_start_one(struct vhost_net *net, goto fail_notifiers; } - r = vhost_dev_start(&net->dev, dev); + r = vhost_dev_start(&net->dev, dev, false); if (r < 0) { goto fail_start; } @@ -308,7 +308,7 @@ fail: if (net->nc->info->poll) { net->nc->info->poll(net->nc, true); } - vhost_dev_stop(&net->dev, dev); + vhost_dev_stop(&net->dev, dev, false); fail_start: vhost_dev_disable_notifiers(&net->dev, dev); fail_notifiers: @@ -329,7 +329,7 @@ static void vhost_net_stop_one(struct vhost_net *net, if (net->nc->info->poll) { net->nc->info->poll(net->nc, true); } - vhost_dev_stop(&net->dev, dev); + vhost_dev_stop(&net->dev, dev, false); if (net->nc->info->stop) { net->nc->info->stop(net->nc); } @@ -606,7 +606,7 @@ err_start: assert(r >= 0); } - vhost_dev_stop(&net->dev, vdev); + vhost_dev_stop(&net->dev, vdev, false); return r; } diff --git a/hw/scsi/vhost-scsi-common.c b/hw/scsi/vhost-scsi-common.c index 767f827e55..18ea5dcfa1 100644 --- a/hw/scsi/vhost-scsi-common.c +++ b/hw/scsi/vhost-scsi-common.c @@ -68,7 +68,7 @@ int vhost_scsi_common_start(VHostSCSICommon *vsc) goto err_guest_notifiers; } - ret = vhost_dev_start(&vsc->dev, vdev); + ret = vhost_dev_start(&vsc->dev, vdev, true); if (ret < 0) { error_report("Error start vhost dev"); goto err_guest_notifiers; @@ -101,7 +101,7 @@ void vhost_scsi_common_stop(VHostSCSICommon *vsc) VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); int ret = 0; - vhost_dev_stop(&vsc->dev, vdev); + vhost_dev_stop(&vsc->dev, vdev, true); if (k->set_guest_notifiers) { ret = k->set_guest_notifiers(qbus->parent, vsc->dev.nvqs, false); diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events index 820dadc26c..14fc5b9bb2 100644 --- a/hw/virtio/trace-events +++ b/hw/virtio/trace-events @@ -9,8 +9,8 @@ vhost_section(const char *name) "%s" vhost_reject_section(const char *name, int d) "%s:%d" vhost_iotlb_miss(void *dev, int step) "%p step %d" vhost_dev_cleanup(void *dev) "%p" -vhost_dev_start(void *dev, const char *name) "%p:%s" -vhost_dev_stop(void *dev, const char *name) "%p:%s" +vhost_dev_start(void *dev, const char *name, bool vrings) "%p:%s vrings:%d" +vhost_dev_stop(void *dev, const char *name, bool vrings) "%p:%s vrings:%d" # vhost-user.c diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c index dc4014cdef..d97b179e6f 100644 --- a/hw/virtio/vhost-user-fs.c +++ b/hw/virtio/vhost-user-fs.c @@ -76,7 +76,7 @@ static void vuf_start(VirtIODevice *vdev) } fs->vhost_dev.acked_features = vdev->guest_features; - ret = vhost_dev_start(&fs->vhost_dev, vdev); + ret = vhost_dev_start(&fs->vhost_dev, vdev, true); if (ret < 0) { error_report("Error starting vhost: %d", -ret); goto err_guest_notifiers; @@ -110,7 +110,7 @@ static void vuf_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&fs->vhost_dev, vdev); + vhost_dev_stop(&fs->vhost_dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false); if (ret < 0) { diff --git a/hw/virtio/vhost-user-gpio.c b/hw/virtio/vhost-user-gpio.c index 5851cb3bc9..0b40ebd15a 100644 --- a/hw/virtio/vhost-user-gpio.c +++ b/hw/virtio/vhost-user-gpio.c @@ -81,7 +81,7 @@ static int vu_gpio_start(VirtIODevice *vdev) */ vhost_ack_features(&gpio->vhost_dev, feature_bits, vdev->guest_features); - ret = vhost_dev_start(&gpio->vhost_dev, vdev); + ret = vhost_dev_start(&gpio->vhost_dev, vdev, false); if (ret < 0) { error_report("Error starting vhost-user-gpio: %d", ret); goto err_guest_notifiers; @@ -139,7 +139,7 @@ static void vu_gpio_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(vhost_dev, vdev); + vhost_dev_stop(vhost_dev, vdev, false); ret = k->set_guest_notifiers(qbus->parent, vhost_dev->nvqs, false); if (ret < 0) { diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c index 1c9f3d20dc..dc5c828ba6 100644 --- a/hw/virtio/vhost-user-i2c.c +++ b/hw/virtio/vhost-user-i2c.c @@ -46,7 +46,7 @@ static void vu_i2c_start(VirtIODevice *vdev) i2c->vhost_dev.acked_features = vdev->guest_features; - ret = vhost_dev_start(&i2c->vhost_dev, vdev); + ret = vhost_dev_start(&i2c->vhost_dev, vdev, true); if (ret < 0) { error_report("Error starting vhost-user-i2c: %d", -ret); goto err_guest_notifiers; @@ -80,7 +80,7 @@ static void vu_i2c_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&i2c->vhost_dev, vdev); + vhost_dev_stop(&i2c->vhost_dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, i2c->vhost_dev.nvqs, false); if (ret < 0) { diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c index f9084cde58..201a39e220 100644 --- a/hw/virtio/vhost-user-rng.c +++ b/hw/virtio/vhost-user-rng.c @@ -47,7 +47,7 @@ static void vu_rng_start(VirtIODevice *vdev) } rng->vhost_dev.acked_features = vdev->guest_features; - ret = vhost_dev_start(&rng->vhost_dev, vdev); + ret = vhost_dev_start(&rng->vhost_dev, vdev, true); if (ret < 0) { error_report("Error starting vhost-user-rng: %d", -ret); goto err_guest_notifiers; @@ -81,7 +81,7 @@ static void vu_rng_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&rng->vhost_dev, vdev); + vhost_dev_stop(&rng->vhost_dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, rng->vhost_dev.nvqs, false); if (ret < 0) { diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-common.c index a67a275de2..d21c72b401 100644 --- a/hw/virtio/vhost-vsock-common.c +++ b/hw/virtio/vhost-vsock-common.c @@ -70,7 +70,7 @@ int vhost_vsock_common_start(VirtIODevice *vdev) } vvc->vhost_dev.acked_features = vdev->guest_features; - ret = vhost_dev_start(&vvc->vhost_dev, vdev); + ret = vhost_dev_start(&vvc->vhost_dev, vdev, true); if (ret < 0) { error_report("Error starting vhost: %d", -ret); goto err_guest_notifiers; @@ -105,7 +105,7 @@ void vhost_vsock_common_stop(VirtIODevice *vdev) return; } - vhost_dev_stop(&vvc->vhost_dev, vdev); + vhost_dev_stop(&vvc->vhost_dev, vdev, true); ret = k->set_guest_notifiers(qbus->parent, vvc->vhost_dev.nvqs, false); if (ret < 0) { diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index d1c4c20b8c..7fb008bc9e 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -1777,15 +1777,36 @@ int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size, return 0; } +static int vhost_dev_set_vring_enable(struct vhost_dev *hdev, int enable) +{ + if (!hdev->vhost_ops->vhost_set_vring_enable) { + return 0; + } + + /* + * For vhost-user devices, if VHOST_USER_F_PROTOCOL_FEATURES has not + * been negotiated, the rings start directly in the enabled state, and + * .vhost_set_vring_enable callback will fail since + * VHOST_USER_SET_VRING_ENABLE is not supported. + */ + if (hdev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER && + !virtio_has_feature(hdev->backend_features, + VHOST_USER_F_PROTOCOL_FEATURES)) { + return 0; + } + + return hdev->vhost_ops->vhost_set_vring_enable(hdev, enable); +} + /* Host notifiers must be enabled at this point. */ -int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) +int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) { int i, r; /* should only be called after backend is connected */ assert(hdev->vhost_ops); - trace_vhost_dev_start(hdev, vdev->name); + trace_vhost_dev_start(hdev, vdev->name, vrings); vdev->vhost_started = true; hdev->started = true; @@ -1830,10 +1851,16 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) goto fail_log; } } + if (vrings) { + r = vhost_dev_set_vring_enable(hdev, true); + if (r) { + goto fail_log; + } + } if (hdev->vhost_ops->vhost_dev_start) { r = hdev->vhost_ops->vhost_dev_start(hdev, true); if (r) { - goto fail_log; + goto fail_start; } } if (vhost_dev_has_iommu(hdev) && @@ -1848,6 +1875,10 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) } } return 0; +fail_start: + if (vrings) { + vhost_dev_set_vring_enable(hdev, false); + } fail_log: vhost_log_put(hdev, false); fail_vq: @@ -1866,18 +1897,21 @@ fail_features: } /* Host notifiers must be enabled at this point. */ -void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) +void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) { int i; /* should only be called after backend is connected */ assert(hdev->vhost_ops); - trace_vhost_dev_stop(hdev, vdev->name); + trace_vhost_dev_stop(hdev, vdev->name, vrings); if (hdev->vhost_ops->vhost_dev_start) { hdev->vhost_ops->vhost_dev_start(hdev, false); } + if (vrings) { + vhost_dev_set_vring_enable(hdev, false); + } for (i = 0; i < hdev->nvqs; ++i) { vhost_virtqueue_stop(hdev, vdev, diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h index 353252ac3e..67a6807fac 100644 --- a/include/hw/virtio/vhost.h +++ b/include/hw/virtio/vhost.h @@ -184,24 +184,26 @@ static inline bool vhost_dev_is_started(struct vhost_dev *hdev) * vhost_dev_start() - start the vhost device * @hdev: common vhost_dev structure * @vdev: the VirtIODevice structure + * @vrings: true to have vrings enabled in this call * * Starts the vhost device. From this point VirtIO feature negotiation * can start and the device can start processing VirtIO transactions. * * Return: 0 on success, < 0 on error. */ -int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev); +int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings); /** * vhost_dev_stop() - stop the vhost device * @hdev: common vhost_dev structure * @vdev: the VirtIODevice structure + * @vrings: true to have vrings disabled in this call * * Stop the vhost device. After the device is stopped the notifiers * can be disabled (@vhost_dev_disable_notifiers) and the device can * be torn down (@vhost_dev_cleanup). */ -void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev); +void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings); /** * DOC: vhost device configuration handling