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Tsirkin" , Gautam Dawar , Liuxiangdong , Stefano Garzarella , Cindy Lu , Eli Cohen , Cornelia Huck , Zhu Lingshan , kvm@vger.kernel.org, "Gonglei (Arei)" , Paolo Bonzini References: <20221108170755.92768-1-eperezma@redhat.com> <20221108170755.92768-11-eperezma@redhat.com> From: Jason Wang In-Reply-To: <20221108170755.92768-11-eperezma@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org 在 2022/11/9 01:07, Eugenio Pérez 写道: > Isolate control virtqueue in its own group, allowing to intercept control > commands but letting dataplane run totally passthrough to the guest. I think we need to tweak the title to "vdpa: Always start CVQ in SVQ mode if possible". Since SVQ for CVQ can't be enabled without ASID support? > > Signed-off-by: Eugenio Pérez > --- > v6: > * Disable control SVQ if the device does not support it because of > features. > > v5: > * Fixing the not adding cvq buffers when x-svq=on is specified. > * Move vring state in vhost_vdpa_get_vring_group instead of using a > parameter. > * Rename VHOST_VDPA_NET_CVQ_PASSTHROUGH to VHOST_VDPA_NET_DATA_ASID > > v4: > * Squash vhost_vdpa_cvq_group_is_independent. > * Rebased on last CVQ start series, that allocated CVQ cmd bufs at load > * Do not check for cvq index on vhost_vdpa_net_prepare, we only have one > that callback registered in that NetClientInfo. > > v3: > * Make asid related queries print a warning instead of returning an > error and stop the start of qemu. > --- > hw/virtio/vhost-vdpa.c | 3 +- > net/vhost-vdpa.c | 138 ++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 132 insertions(+), 9 deletions(-) > > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c > index e3914fa40e..6401e7efb1 100644 > --- a/hw/virtio/vhost-vdpa.c > +++ b/hw/virtio/vhost-vdpa.c > @@ -648,7 +648,8 @@ static int vhost_vdpa_set_backend_cap(struct vhost_dev *dev) > { > uint64_t features; > uint64_t f = 0x1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2 | > - 0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH; > + 0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH | > + 0x1ULL << VHOST_BACKEND_F_IOTLB_ASID; > int r; > > if (vhost_vdpa_call(dev, VHOST_GET_BACKEND_FEATURES, &features)) { > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c > index 02780ee37b..7245ea70c6 100644 > --- a/net/vhost-vdpa.c > +++ b/net/vhost-vdpa.c > @@ -38,6 +38,9 @@ typedef struct VhostVDPAState { > void *cvq_cmd_out_buffer; > virtio_net_ctrl_ack *status; > > + /* Number of address spaces supported by the device */ > + unsigned address_space_num; I'm not sure this is the best place to store thing like this since it can cause confusion. We will have multiple VhostVDPAState when multiqueue is enabled. > + > /* The device always have SVQ enabled */ > bool always_svq; > bool started; > @@ -101,6 +104,9 @@ static const uint64_t vdpa_svq_device_features = > BIT_ULL(VIRTIO_NET_F_RSC_EXT) | > BIT_ULL(VIRTIO_NET_F_STANDBY); > > +#define VHOST_VDPA_NET_DATA_ASID 0 > +#define VHOST_VDPA_NET_CVQ_ASID 1 > + > VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc) > { > VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); > @@ -242,6 +248,34 @@ static NetClientInfo net_vhost_vdpa_info = { > .check_peer_type = vhost_vdpa_check_peer_type, > }; > > +static uint32_t vhost_vdpa_get_vring_group(int device_fd, unsigned vq_index) > +{ > + struct vhost_vring_state state = { > + .index = vq_index, > + }; > + int r = ioctl(device_fd, VHOST_VDPA_GET_VRING_GROUP, &state); > + > + return r < 0 ? 0 : state.num; Assume 0 when ioctl() fail is probably not a good idea: errors in ioctl might be hidden. It would be better to fallback to 0 when ASID is not supported. > +} > + > +static int vhost_vdpa_set_address_space_id(struct vhost_vdpa *v, > + unsigned vq_group, > + unsigned asid_num) > +{ > + struct vhost_vring_state asid = { > + .index = vq_group, > + .num = asid_num, > + }; > + int ret; > + > + ret = ioctl(v->device_fd, VHOST_VDPA_SET_GROUP_ASID, &asid); > + if (unlikely(ret < 0)) { > + warn_report("Can't set vq group %u asid %u, errno=%d (%s)", > + asid.index, asid.num, errno, g_strerror(errno)); > + } > + return ret; > +} > + > static void vhost_vdpa_cvq_unmap_buf(struct vhost_vdpa *v, void *addr) > { > VhostIOVATree *tree = v->iova_tree; > @@ -316,11 +350,54 @@ dma_map_err: > static int vhost_vdpa_net_cvq_start(NetClientState *nc) > { > VhostVDPAState *s; > - int r; > + struct vhost_vdpa *v; > + uint32_t cvq_group; > + int cvq_index, r; > > assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); > > s = DO_UPCAST(VhostVDPAState, nc, nc); > + v = &s->vhost_vdpa; > + > + v->listener_shadow_vq = s->always_svq; > + v->shadow_vqs_enabled = s->always_svq; > + s->vhost_vdpa.address_space_id = VHOST_VDPA_NET_DATA_ASID; > + > + if (s->always_svq) { > + goto out; > + } > + > + if (s->address_space_num < 2) { > + return 0; > + } > + > + if (!vhost_vdpa_net_valid_svq_features(v->dev->features, NULL)) { > + return 0; > + } Any reason we do the above check during the start/stop? It should be easier to do that in the initialization. > + > + /** > + * Check if all the virtqueues of the virtio device are in a different vq > + * than the last vq. VQ group of last group passed in cvq_group. > + */ > + cvq_index = v->dev->vq_index_end - 1; > + cvq_group = vhost_vdpa_get_vring_group(v->device_fd, cvq_index); > + for (int i = 0; i < cvq_index; ++i) { > + uint32_t group = vhost_vdpa_get_vring_group(v->device_fd, i); > + > + if (unlikely(group == cvq_group)) { > + warn_report("CVQ %u group is the same as VQ %u one (%u)", cvq_group, > + i, group); > + return 0; > + } > + } > + > + r = vhost_vdpa_set_address_space_id(v, cvq_group, VHOST_VDPA_NET_CVQ_ASID); > + if (r == 0) { > + v->shadow_vqs_enabled = true; > + s->vhost_vdpa.address_space_id = VHOST_VDPA_NET_CVQ_ASID; > + } > + > +out: > if (!s->vhost_vdpa.shadow_vqs_enabled) { > return 0; > } > @@ -542,12 +619,38 @@ static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = { > .avail_handler = vhost_vdpa_net_handle_ctrl_avail, > }; > > +static uint32_t vhost_vdpa_get_as_num(int vdpa_device_fd) > +{ > + uint64_t features; > + unsigned num_as; > + int r; > + > + r = ioctl(vdpa_device_fd, VHOST_GET_BACKEND_FEATURES, &features); > + if (unlikely(r < 0)) { > + warn_report("Cannot get backend features"); > + return 1; > + } > + > + if (!(features & BIT_ULL(VHOST_BACKEND_F_IOTLB_ASID))) { > + return 1; > + } > + > + r = ioctl(vdpa_device_fd, VHOST_VDPA_GET_AS_NUM, &num_as); > + if (unlikely(r < 0)) { > + warn_report("Cannot retrieve number of supported ASs"); > + return 1; Let's return error here. This help to identify bugs of qemu or kernel. > + } > + > + return num_as; > +} > + > static NetClientState *net_vhost_vdpa_init(NetClientState *peer, > const char *device, > const char *name, > int vdpa_device_fd, > int queue_pair_index, > int nvqs, > + unsigned nas, > bool is_datapath, > bool svq, > VhostIOVATree *iova_tree) > @@ -566,6 +669,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer, > qemu_set_info_str(nc, TYPE_VHOST_VDPA); > s = DO_UPCAST(VhostVDPAState, nc, nc); > > + s->address_space_num = nas; > s->vhost_vdpa.device_fd = vdpa_device_fd; > s->vhost_vdpa.index = queue_pair_index; > s->always_svq = svq; > @@ -652,6 +756,8 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > g_autoptr(VhostIOVATree) iova_tree = NULL; > NetClientState *nc; > int queue_pairs, r, i = 0, has_cvq = 0; > + unsigned num_as = 1; > + bool svq_cvq; > > assert(netdev->type == NET_CLIENT_DRIVER_VHOST_VDPA); > opts = &netdev->u.vhost_vdpa; > @@ -693,12 +799,28 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > return queue_pairs; > } > > - if (opts->x_svq) { > - struct vhost_vdpa_iova_range iova_range; > + svq_cvq = opts->x_svq; > + if (has_cvq && !opts->x_svq) { > + num_as = vhost_vdpa_get_as_num(vdpa_device_fd); > + svq_cvq = num_as > 1; > + } The above check is not easy to follow, how about? svq_cvq = vhost_vdpa_get_as_num() > 1 ? true : opts->x_svq; > + > + if (opts->x_svq || svq_cvq) { Any chance we can have opts->x_svq = true but svq_cvq = false? Checking svq_cvq seems sufficient here. > + Error *warn = NULL; > > - if (!vhost_vdpa_net_valid_svq_features(features, errp)) { > - goto err_svq; > + svq_cvq = vhost_vdpa_net_valid_svq_features(features, > + opts->x_svq ? errp : &warn); > + if (!svq_cvq) { Same question as above. > + if (opts->x_svq) { > + goto err_svq; > + } else { > + warn_reportf_err(warn, "Cannot shadow CVQ: "); > + } > } > + } > + > + if (opts->x_svq || svq_cvq) { > + struct vhost_vdpa_iova_range iova_range; > > vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range); > iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last); > @@ -708,15 +830,15 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > > for (i = 0; i < queue_pairs; i++) { > ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name, > - vdpa_device_fd, i, 2, true, opts->x_svq, > - iova_tree); > + vdpa_device_fd, i, 2, num_as, true, I don't get why we need pass num_as to a specific vhost_vdpa structure. It should be sufficient to pass asid there. Thanks > + opts->x_svq, iova_tree); > if (!ncs[i]) > goto err; > } > > if (has_cvq) { > nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name, > - vdpa_device_fd, i, 1, false, > + vdpa_device_fd, i, 1, num_as, false, > opts->x_svq, iova_tree); > if (!nc) > goto err;