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 <eperezma@xxxxxxxxxx>
---
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;
