Jason Wang
2023-Feb-27 07:04 UTC
[PATCH v4 01/15] vdpa net: move iova tree creation from init to start
? 2023/2/24 23:54, Eugenio P?rez ??:> Only create iova_tree if and when it is needed. > > The cleanup keeps being responsible of last VQ but this change allows it > to merge both cleanup functions. > > Signed-off-by: Eugenio P?rez <eperezma at redhat.com> > Acked-by: Jason Wang <jasowang at redhat.com> > --- > v4: > * Remove leak of iova_tree because double allocation > * Document better the sharing of IOVA tree between data and CVQ > --- > net/vhost-vdpa.c | 113 ++++++++++++++++++++++++++++++++++------------- > 1 file changed, 83 insertions(+), 30 deletions(-) > > diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c > index de5ed8ff22..b89c99066a 100644 > --- a/net/vhost-vdpa.c > +++ b/net/vhost-vdpa.c > @@ -178,13 +178,9 @@ err_init: > static void vhost_vdpa_cleanup(NetClientState *nc) > { > VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); > - struct vhost_dev *dev = &s->vhost_net->dev; > > qemu_vfree(s->cvq_cmd_out_buffer); > qemu_vfree(s->status); > - if (dev->vq_index + dev->nvqs == dev->vq_index_end) { > - g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete); > - } > if (s->vhost_net) { > vhost_net_cleanup(s->vhost_net); > g_free(s->vhost_net); > @@ -234,10 +230,64 @@ static ssize_t vhost_vdpa_receive(NetClientState *nc, const uint8_t *buf, > return size; > } > > +/** From any vdpa net client, get the netclient of first queue pair */ > +static VhostVDPAState *vhost_vdpa_net_first_nc_vdpa(VhostVDPAState *s) > +{ > + NICState *nic = qemu_get_nic(s->nc.peer); > + NetClientState *nc0 = qemu_get_peer(nic->ncs, 0); > + > + return DO_UPCAST(VhostVDPAState, nc, nc0); > +} > + > +static void vhost_vdpa_net_data_start_first(VhostVDPAState *s) > +{ > + struct vhost_vdpa *v = &s->vhost_vdpa; > + > + if (v->shadow_vqs_enabled) { > + v->iova_tree = vhost_iova_tree_new(v->iova_range.first, > + v->iova_range.last); > + } > +} > + > +static int vhost_vdpa_net_data_start(NetClientState *nc) > +{ > + VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); > + struct vhost_vdpa *v = &s->vhost_vdpa; > + > + assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); > + > + if (v->index == 0) { > + vhost_vdpa_net_data_start_first(s); > + return 0; > + } > + > + if (v->shadow_vqs_enabled) { > + VhostVDPAState *s0 = vhost_vdpa_net_first_nc_vdpa(s); > + v->iova_tree = s0->vhost_vdpa.iova_tree; > + } > + > + return 0; > +} > + > +static void vhost_vdpa_net_client_stop(NetClientState *nc) > +{ > + VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc); > + struct vhost_dev *dev; > + > + assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA); > + > + dev = s->vhost_vdpa.dev; > + if (dev->vq_index + dev->nvqs == dev->vq_index_end) { > + g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete); > + } > +} > + > static NetClientInfo net_vhost_vdpa_info = { > .type = NET_CLIENT_DRIVER_VHOST_VDPA, > .size = sizeof(VhostVDPAState), > .receive = vhost_vdpa_receive, > + .start = vhost_vdpa_net_data_start, > + .stop = vhost_vdpa_net_client_stop,Looking at the implementation, it seems nothing net specific, any reason we can't simply use vhost_vdpa_dev_start()?> .cleanup = vhost_vdpa_cleanup, > .has_vnet_hdr = vhost_vdpa_has_vnet_hdr, > .has_ufo = vhost_vdpa_has_ufo, > @@ -351,7 +401,7 @@ dma_map_err: > > static int vhost_vdpa_net_cvq_start(NetClientState *nc) > { > - VhostVDPAState *s; > + VhostVDPAState *s, *s0; > struct vhost_vdpa *v; > uint64_t backend_features; > int64_t cvq_group; > @@ -415,8 +465,6 @@ static int vhost_vdpa_net_cvq_start(NetClientState *nc) > return r; > } > > - v->iova_tree = vhost_iova_tree_new(v->iova_range.first, > - v->iova_range.last); > v->shadow_vqs_enabled = true; > s->vhost_vdpa.address_space_id = VHOST_VDPA_NET_CVQ_ASID; > > @@ -425,6 +473,27 @@ out: > return 0; > } > > + s0 = vhost_vdpa_net_first_nc_vdpa(s); > + if (s0->vhost_vdpa.iova_tree) { > + /* > + * SVQ is already configured for all virtqueues. Reuse IOVA tree for > + * simplicity, wether CVQ shares ASID with guest or not, because:Typo, should be "whether", or "regardless of whether"(not a native speaker). Other looks good. Thanks> + * - Memory listener need access to guest's memory addresses allocated > + * in the IOVA tree. > + * - There should be plenty of IOVA address space for both ASID not to > + * worry about collisions between them. Guest's translations are > + * still validated with virtio virtqueue_pop so there is no risk for > + * the guest to access memory it shouldn't. > + * > + * To allocate a iova tree per ASID is doable but it complicates the > + * code and it is not worth for the moment. > + */ > + v->iova_tree = s0->vhost_vdpa.iova_tree; > + } else { > + v->iova_tree = vhost_iova_tree_new(v->iova_range.first, > + v->iova_range.last); > + } > + > r = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer, > vhost_vdpa_net_cvq_cmd_page_len(), false); > if (unlikely(r < 0)) { > @@ -449,15 +518,9 @@ static void vhost_vdpa_net_cvq_stop(NetClientState *nc) > if (s->vhost_vdpa.shadow_vqs_enabled) { > vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer); > vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->status); > - if (!s->always_svq) { > - /* > - * If only the CVQ is shadowed we can delete this safely. > - * If all the VQs are shadows this will be needed by the time the > - * device is started again to register SVQ vrings and similar. > - */ > - g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete); > - } > } > + > + vhost_vdpa_net_client_stop(nc); > } > > static ssize_t vhost_vdpa_net_cvq_add(VhostVDPAState *s, size_t out_len, > @@ -667,8 +730,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer, > int nvqs, > bool is_datapath, > bool svq, > - struct vhost_vdpa_iova_range iova_range, > - VhostIOVATree *iova_tree) > + struct vhost_vdpa_iova_range iova_range) > { > NetClientState *nc = NULL; > VhostVDPAState *s; > @@ -690,7 +752,6 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer, > s->vhost_vdpa.shadow_vqs_enabled = svq; > s->vhost_vdpa.iova_range = iova_range; > s->vhost_vdpa.shadow_data = svq; > - s->vhost_vdpa.iova_tree = iova_tree; > if (!is_datapath) { > s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(), > vhost_vdpa_net_cvq_cmd_page_len()); > @@ -760,7 +821,6 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > uint64_t features; > int vdpa_device_fd; > g_autofree NetClientState **ncs = NULL; > - g_autoptr(VhostIOVATree) iova_tree = NULL; > struct vhost_vdpa_iova_range iova_range; > NetClientState *nc; > int queue_pairs, r, i = 0, has_cvq = 0; > @@ -812,12 +872,8 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > goto err; > } > > - if (opts->x_svq) { > - if (!vhost_vdpa_net_valid_svq_features(features, errp)) { > - goto err_svq; > - } > - > - iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last); > + if (opts->x_svq && !vhost_vdpa_net_valid_svq_features(features, errp)) { > + goto err; > } > > ncs = g_malloc0(sizeof(*ncs) * queue_pairs); > @@ -825,7 +881,7 @@ 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_range, iova_tree); > + iova_range); > if (!ncs[i]) > goto err; > } > @@ -833,13 +889,11 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name, > if (has_cvq) { > nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name, > vdpa_device_fd, i, 1, false, > - opts->x_svq, iova_range, iova_tree); > + opts->x_svq, iova_range); > if (!nc) > goto err; > } > > - /* iova_tree ownership belongs to last NetClientState */ > - g_steal_pointer(&iova_tree); > return 0; > > err: > @@ -849,7 +903,6 @@ err: > } > } > > -err_svq: > qemu_close(vdpa_device_fd); > > return -1;