On Sat, Nov 25, 2023 at 1:14 AM Eugenio Pérez <epere...@redhat.com> wrote:
>
> It will hold properties shared among all vhost_vdpa instances associated
> with of the same device. For example, we just need one iova_tree or one
> memory listener for the entire device.
>
> Next patches will register the vhost_vdpa memory listener at the
> beginning of the VM migration at the destination. This enables QEMU to
> map the memory to the device before stopping the VM at the source,
> instead of doing while both source and destination are stopped, thus
> minimizing the downtime.
>
> However, the destination QEMU is unaware of which vhost_vdpa struct will
> register its memory_listener. If the source guest has CVQ enabled, it
> will be the one associated with the CVQ. Otherwise, it will be the
> first one.
>
> Save the memory operations related members in a common place rather than
> always in the first / last vhost_vdpa.
Great.
Patch looks good but I think we probably need a better name like
VhostVDPAParent?
And it would be better in the future if we can convert it to QOM.
Thanks
>
> Signed-off-by: Eugenio Pérez <epere...@redhat.com>
> ---
> include/hw/virtio/vhost-vdpa.h | 5 +++++
> net/vhost-vdpa.c | 24 ++++++++++++++++++++++--
> 2 files changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
> index 5407d54fd7..eb1a56d75a 100644
> --- a/include/hw/virtio/vhost-vdpa.h
> +++ b/include/hw/virtio/vhost-vdpa.h
> @@ -30,6 +30,10 @@ typedef struct VhostVDPAHostNotifier {
> void *addr;
> } VhostVDPAHostNotifier;
>
> +/* Info shared by all vhost_vdpa device models */
> +typedef struct vhost_vdpa_shared {
> +} VhostVDPAShared;
> +
> typedef struct vhost_vdpa {
> int device_fd;
> int index;
> @@ -46,6 +50,7 @@ typedef struct vhost_vdpa {
> bool suspended;
> /* IOVA mapping used by the Shadow Virtqueue */
> VhostIOVATree *iova_tree;
> + VhostVDPAShared *shared;
> GPtrArray *shadow_vqs;
> const VhostShadowVirtqueueOps *shadow_vq_ops;
> void *shadow_vq_ops_opaque;
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index d0614d7954..8b661b9e6d 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -240,6 +240,10 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
> qemu_close(s->vhost_vdpa.device_fd);
> s->vhost_vdpa.device_fd = -1;
> }
> + if (s->vhost_vdpa.index != 0) {
> + return;
> + }
> + g_free(s->vhost_vdpa.shared);
> }
>
> /** Dummy SetSteeringEBPF to support RSS for vhost-vdpa backend */
> @@ -1661,6 +1665,7 @@ static NetClientState
> *net_vhost_vdpa_init(NetClientState *peer,
> bool svq,
> struct vhost_vdpa_iova_range
> iova_range,
> uint64_t features,
> + VhostVDPAShared *shared,
> Error **errp)
> {
> NetClientState *nc = NULL;
> @@ -1696,6 +1701,7 @@ static NetClientState
> *net_vhost_vdpa_init(NetClientState *peer,
> if (queue_pair_index == 0) {
> vhost_vdpa_net_valid_svq_features(features,
> &s->vhost_vdpa.migration_blocker);
> + s->vhost_vdpa.shared = g_new0(VhostVDPAShared, 1);
> } else if (!is_datapath) {
> s->cvq_cmd_out_buffer = mmap(NULL, vhost_vdpa_net_cvq_cmd_page_len(),
> PROT_READ | PROT_WRITE,
> @@ -1708,11 +1714,16 @@ static NetClientState
> *net_vhost_vdpa_init(NetClientState *peer,
> s->vhost_vdpa.shadow_vq_ops_opaque = s;
> s->cvq_isolated = cvq_isolated;
> }
> + if (queue_pair_index != 0) {
> + s->vhost_vdpa.shared = shared;
> + }
> +
> ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
> if (ret) {
> qemu_del_net_client(nc);
> return NULL;
> }
> +
> return nc;
> }
>
> @@ -1824,17 +1835,26 @@ int net_init_vhost_vdpa(const Netdev *netdev, const
> char *name,
> ncs = g_malloc0(sizeof(*ncs) * queue_pairs);
>
> for (i = 0; i < queue_pairs; i++) {
> + VhostVDPAShared *shared = NULL;
> +
> + if (i) {
> + shared = DO_UPCAST(VhostVDPAState, nc,
> ncs[0])->vhost_vdpa.shared;
> + }
> ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> vdpa_device_fd, i, 2, true, opts->x_svq,
> - iova_range, features, errp);
> + iova_range, features, shared, errp);
> if (!ncs[i])
> goto err;
> }
>
> if (has_cvq) {
> + VhostVDPAState *s0 = DO_UPCAST(VhostVDPAState, nc, ncs[0]);
> + VhostVDPAShared *shared = s0->vhost_vdpa.shared;
> +
> nc = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
> vdpa_device_fd, i, 1, false,
> - opts->x_svq, iova_range, features, errp);
> + opts->x_svq, iova_range, features, shared,
> + errp);
> if (!nc)
> goto err;
> }
> --
> 2.39.3
>
