[PATCH v3 00/19] vdpa net devices Rx filter change notification with Shadow VQ

[PATCH v3 00/19] vdpa net devices Rx filter change notification with Shadow VQ

[Eugenio Pérez]

Control virtqueue is used by networking device for accepting various
commands from the driver. It's a must to support advanced configurations.

Rx filtering event is issues by qemu when device's MAC address changed once and
the previous one has not been queried by external agents.

Shadow VirtQueue (SVQ) already makes possible tracking the state of virtqueues,
effectively intercepting them so qemu can track what regions of memory are
dirty because device action and needs migration. However, this does not solve
networking device state seen by the driver because CVQ messages, like changes
on MAC addresses from the driver.

This series uses SVQ infrastructure to intercept networking control messages
used by the device. This way, qemu is able to update VirtIONet device model and
react to them. In particular, this series enables rx filter change
notification.

This is a prerequisite to achieve net vdpa device with CVQ live migration.
It's a stripped down version of [1], with error paths checked and no migration
enabled.

First nine patches reorder and clean code base so its easier to apply later
ones. No functional change should be noticed from these changes.

Patches from 11 to 14 enable SVQ API to make other parts of qemu to interact
with it. In particular, they will be used by vhost-vdpa net to handle CVQ
messages.

Patches 15 to 17 enable the update of the virtio-net device model for each
CVQ message acknowledged by the device.

Last patches enable x-svq parameter, forbidding device migration since it is
not restored in the destination's vdpa device yet. This will be added in later
series, using this work.

Comments are welcome.
v3:
- Replace SVQElement with SVQDescState

v2:
- (Comments from series [1]).
- Active poll for CVQ answer instead of relay on async used callback
- Do not offer a new buffer to device but reuse qemu's
- Use vhost_svq_add instead of not needed vhost_svq_inject
- Delete used and detach callbacks, not needed anymore
- Embed members of SVQElement in VirtQueueElement
- Reuse the same buffers for all CVQ commands

[1] https://patchwork.kernel.org/project/qemu-devel/cover/20220706184008.1649478-1-eperezma@redhat.com/

Eugenio Pérez (19):
  vhost: move descriptor translation to vhost_svq_vring_write_descs
  virtio-net: Expose MAC_TABLE_ENTRIES
  virtio-net: Expose ctrl virtqueue logic
  vhost: Reorder vhost_svq_kick
  vhost: Move vhost_svq_kick call to vhost_svq_add
  vhost: Check for queue full at vhost_svq_add
  vhost: Decouple vhost_svq_add from VirtQueueElement
  vhost: Add SVQDescState
  vhost: Track number of descs in SVQDescState
  vhost: add vhost_svq_push_elem
  vhost: Expose vhost_svq_add
  vhost: add vhost_svq_poll
  vhost: Add svq avail_handler callback
  vdpa: Export vhost_vdpa_dma_map and unmap calls
  vdpa: manual forward CVQ buffers
  vdpa: Buffer CVQ support on shadow virtqueue
  vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs
  vdpa: Add device migration blocker
  vdpa: Add x-svq to NetdevVhostVDPAOptions

 qapi/net.json                      |   9 +-
 hw/virtio/vhost-shadow-virtqueue.h |  52 ++++-
 include/hw/virtio/vhost-vdpa.h     |   8 +
 include/hw/virtio/virtio-net.h     |   7 +
 hw/net/virtio-net.c                |  85 ++++---
 hw/virtio/vhost-shadow-virtqueue.c | 202 +++++++++++-----
 hw/virtio/vhost-vdpa.c             |  25 +-
 net/vhost-vdpa.c                   | 357 +++++++++++++++++++++++++++--
 8 files changed, 627 insertions(+), 118 deletions(-)

-- 
2.31.1

[PATCH v3 01/19] vhost: move descriptor translation to vhost_svq_vring_write_descs

[Eugenio Pérez]

It's done for both in and out descriptors so it's better placed here.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 38 +++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 56c96ebd13..e2184a4481 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -122,17 +122,35 @@ static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq,
     return true;
 }
 
-static void vhost_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
-                                    const struct iovec *iovec, size_t num,
-                                    bool more_descs, bool write)
+/**
+ * Write descriptors to SVQ vring
+ *
+ * @svq: The shadow virtqueue
+ * @sg: Cache for hwaddr
+ * @iovec: The iovec from the guest
+ * @num: iovec length
+ * @more_descs: True if more descriptors come in the chain
+ * @write: True if they are writeable descriptors
+ *
+ * Return true if success, false otherwise and print error.
+ */
+static bool vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
+                                        const struct iovec *iovec, size_t num,
+                                        bool more_descs, bool write)
 {
     uint16_t i = svq->free_head, last = svq->free_head;
     unsigned n;
     uint16_t flags = write ? cpu_to_le16(VRING_DESC_F_WRITE) : 0;
     vring_desc_t *descs = svq->vring.desc;
+    bool ok;
 
     if (num == 0) {
-        return;
+        return true;
+    }
+
+    ok = vhost_svq_translate_addr(svq, sg, iovec, num);
+    if (unlikely(!ok)) {
+        return false;
     }
 
     for (n = 0; n < num; n++) {
@@ -150,6 +168,7 @@ static void vhost_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
     }
 
     svq->free_head = le16_to_cpu(svq->desc_next[last]);
+    return true;
 }
 
 static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
@@ -169,21 +188,18 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
         return false;
     }
 
-    ok = vhost_svq_translate_addr(svq, sgs, elem->out_sg, elem->out_num);
+    ok = vhost_svq_vring_write_descs(svq, sgs, elem->out_sg, elem->out_num,
+                                     elem->in_num > 0, false);
     if (unlikely(!ok)) {
         return false;
     }
-    vhost_vring_write_descs(svq, sgs, elem->out_sg, elem->out_num,
-                            elem->in_num > 0, false);
-
 
-    ok = vhost_svq_translate_addr(svq, sgs, elem->in_sg, elem->in_num);
+    ok = vhost_svq_vring_write_descs(svq, sgs, elem->in_sg, elem->in_num, false,
+                                     true);
     if (unlikely(!ok)) {
         return false;
     }
 
-    vhost_vring_write_descs(svq, sgs, elem->in_sg, elem->in_num, false, true);
-
     /*
      * Put the entry in the available array (but don't update avail->idx until
      * they do sync).
-- 
2.31.1

[PATCH v3 02/19] virtio-net: Expose MAC_TABLE_ENTRIES

[Eugenio Pérez]

vhost-vdpa control virtqueue needs to know the maximum entries supported
by the virtio-net device, so we know if it is possible to apply the
filter.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/virtio-net.h | 3 +++
 hw/net/virtio-net.c            | 1 -
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index eb87032627..cce1c554f7 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -35,6 +35,9 @@ OBJECT_DECLARE_SIMPLE_TYPE(VirtIONet, VIRTIO_NET)
  * and latency. */
 #define TX_BURST 256
 
+/* Maximum VIRTIO_NET_CTRL_MAC_TABLE_SET unicast + multicast entries. */
+#define MAC_TABLE_ENTRIES    64
+
 typedef struct virtio_net_conf
 {
     uint32_t txtimer;
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 7ad948ee7c..f83e96e4ce 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -49,7 +49,6 @@
 
 #define VIRTIO_NET_VM_VERSION    11
 
-#define MAC_TABLE_ENTRIES    64
 #define MAX_VLAN    (1 << 12)   /* Per 802.1Q definition */
 
 /* previously fixed value */
-- 
2.31.1

[PATCH v3 03/19] virtio-net: Expose ctrl virtqueue logic

[Eugenio Pérez]

This allows external vhost-net devices to modify the state of the
VirtIO device model once the vhost-vdpa device has acknowledged the
control commands.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/virtio-net.h |  4 ++
 hw/net/virtio-net.c            | 84 ++++++++++++++++++++--------------
 2 files changed, 53 insertions(+), 35 deletions(-)

diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index cce1c554f7..ef234ffe7e 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -221,6 +221,10 @@ struct VirtIONet {
     struct EBPFRSSContext ebpf_rss;
 };
 
+size_t virtio_net_handle_ctrl_iov(VirtIODevice *vdev,
+                                  const struct iovec *in_sg, unsigned in_num,
+                                  const struct iovec *out_sg,
+                                  unsigned out_num);
 void virtio_net_set_netclient_name(VirtIONet *n, const char *name,
                                    const char *type);
 
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index f83e96e4ce..dd0d056fde 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1433,57 +1433,71 @@ static int virtio_net_handle_mq(VirtIONet *n, uint8_t cmd,
     return VIRTIO_NET_OK;
 }
 
-static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
+size_t virtio_net_handle_ctrl_iov(VirtIODevice *vdev,
+                                  const struct iovec *in_sg, unsigned in_num,
+                                  const struct iovec *out_sg,
+                                  unsigned out_num)
 {
     VirtIONet *n = VIRTIO_NET(vdev);
     struct virtio_net_ctrl_hdr ctrl;
     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
-    VirtQueueElement *elem;
     size_t s;
     struct iovec *iov, *iov2;
-    unsigned int iov_cnt;
+
+    if (iov_size(in_sg, in_num) < sizeof(status) ||
+        iov_size(out_sg, out_num) < sizeof(ctrl)) {
+        virtio_error(vdev, "virtio-net ctrl missing headers");
+        return 0;
+    }
+
+    iov2 = iov = g_memdup2(out_sg, sizeof(struct iovec) * out_num);
+    s = iov_to_buf(iov, out_num, 0, &ctrl, sizeof(ctrl));
+    iov_discard_front(&iov, &out_num, sizeof(ctrl));
+    if (s != sizeof(ctrl)) {
+        status = VIRTIO_NET_ERR;
+    } else if (ctrl.class == VIRTIO_NET_CTRL_RX) {
+        status = virtio_net_handle_rx_mode(n, ctrl.cmd, iov, out_num);
+    } else if (ctrl.class == VIRTIO_NET_CTRL_MAC) {
+        status = virtio_net_handle_mac(n, ctrl.cmd, iov, out_num);
+    } else if (ctrl.class == VIRTIO_NET_CTRL_VLAN) {
+        status = virtio_net_handle_vlan_table(n, ctrl.cmd, iov, out_num);
+    } else if (ctrl.class == VIRTIO_NET_CTRL_ANNOUNCE) {
+        status = virtio_net_handle_announce(n, ctrl.cmd, iov, out_num);
+    } else if (ctrl.class == VIRTIO_NET_CTRL_MQ) {
+        status = virtio_net_handle_mq(n, ctrl.cmd, iov, out_num);
+    } else if (ctrl.class == VIRTIO_NET_CTRL_GUEST_OFFLOADS) {
+        status = virtio_net_handle_offloads(n, ctrl.cmd, iov, out_num);
+    }
+
+    s = iov_from_buf(in_sg, in_num, 0, &status, sizeof(status));
+    assert(s == sizeof(status));
+
+    g_free(iov2);
+    return sizeof(status);
+}
+
+static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtQueueElement *elem;
 
     for (;;) {
+        size_t written;
         elem = virtqueue_pop(vq, sizeof(VirtQueueElement));
         if (!elem) {
             break;
         }
-        if (iov_size(elem->in_sg, elem->in_num) < sizeof(status) ||
-            iov_size(elem->out_sg, elem->out_num) < sizeof(ctrl)) {
-            virtio_error(vdev, "virtio-net ctrl missing headers");
+
+        written = virtio_net_handle_ctrl_iov(vdev, elem->in_sg, elem->in_num,
+                                             elem->out_sg, elem->out_num);
+        if (written > 0) {
+            virtqueue_push(vq, elem, written);
+            virtio_notify(vdev, vq);
+            g_free(elem);
+        } else {
             virtqueue_detach_element(vq, elem, 0);
             g_free(elem);
             break;
         }
-
-        iov_cnt = elem->out_num;
-        iov2 = iov = g_memdup2(elem->out_sg,
-                               sizeof(struct iovec) * elem->out_num);
-        s = iov_to_buf(iov, iov_cnt, 0, &ctrl, sizeof(ctrl));
-        iov_discard_front(&iov, &iov_cnt, sizeof(ctrl));
-        if (s != sizeof(ctrl)) {
-            status = VIRTIO_NET_ERR;
-        } else if (ctrl.class == VIRTIO_NET_CTRL_RX) {
-            status = virtio_net_handle_rx_mode(n, ctrl.cmd, iov, iov_cnt);
-        } else if (ctrl.class == VIRTIO_NET_CTRL_MAC) {
-            status = virtio_net_handle_mac(n, ctrl.cmd, iov, iov_cnt);
-        } else if (ctrl.class == VIRTIO_NET_CTRL_VLAN) {
-            status = virtio_net_handle_vlan_table(n, ctrl.cmd, iov, iov_cnt);
-        } else if (ctrl.class == VIRTIO_NET_CTRL_ANNOUNCE) {
-            status = virtio_net_handle_announce(n, ctrl.cmd, iov, iov_cnt);
-        } else if (ctrl.class == VIRTIO_NET_CTRL_MQ) {
-            status = virtio_net_handle_mq(n, ctrl.cmd, iov, iov_cnt);
-        } else if (ctrl.class == VIRTIO_NET_CTRL_GUEST_OFFLOADS) {
-            status = virtio_net_handle_offloads(n, ctrl.cmd, iov, iov_cnt);
-        }
-
-        s = iov_from_buf(elem->in_sg, elem->in_num, 0, &status, sizeof(status));
-        assert(s == sizeof(status));
-
-        virtqueue_push(vq, elem, sizeof(status));
-        virtio_notify(vdev, vq);
-        g_free(iov2);
-        g_free(elem);
     }
 }
 
-- 
2.31.1

[PATCH v3 04/19] vhost: Reorder vhost_svq_kick

[Eugenio Pérez]

Future code needs to call it from vhost_svq_add.

No functional change intended.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index e2184a4481..fd1839cec5 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -215,6 +215,20 @@ static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
     return true;
 }
 
+static void vhost_svq_kick(VhostShadowVirtqueue *svq)
+{
+    /*
+     * We need to expose the available array entries before checking the used
+     * flags
+     */
+    smp_mb();
+    if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
+        return;
+    }
+
+    event_notifier_set(&svq->hdev_kick);
+}
+
 /**
  * Add an element to a SVQ.
  *
@@ -235,20 +249,6 @@ static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
     return true;
 }
 
-static void vhost_svq_kick(VhostShadowVirtqueue *svq)
-{
-    /*
-     * We need to expose the available array entries before checking the used
-     * flags
-     */
-    smp_mb();
-    if (svq->vring.used->flags & VRING_USED_F_NO_NOTIFY) {
-        return;
-    }
-
-    event_notifier_set(&svq->hdev_kick);
-}
-
 /**
  * Forward available buffers.
  *
-- 
2.31.1

[PATCH v3 05/19] vhost: Move vhost_svq_kick call to vhost_svq_add

[Eugenio Pérez]

The series needs to expose vhost_svq_add with full functionality,
including kick

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index fd1839cec5..e5a4a62daa 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -246,6 +246,7 @@ static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
     }
 
     svq->ring_id_maps[qemu_head] = elem;
+    vhost_svq_kick(svq);
     return true;
 }
 
@@ -306,7 +307,6 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
                 /* VQ is broken, just return and ignore any other kicks */
                 return;
             }
-            vhost_svq_kick(svq);
         }
 
         virtio_queue_set_notification(svq->vq, true);
-- 
2.31.1

[PATCH v3 06/19] vhost: Check for queue full at vhost_svq_add

[Eugenio Pérez]

The series need to expose vhost_svq_add with full functionality,
including checking for full queue.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 59 +++++++++++++++++-------------
 1 file changed, 33 insertions(+), 26 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index e5a4a62daa..aee9891a67 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -233,21 +233,29 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
  * Add an element to a SVQ.
  *
  * The caller must check that there is enough slots for the new element. It
- * takes ownership of the element: In case of failure, it is free and the SVQ
- * is considered broken.
+ * takes ownership of the element: In case of failure not ENOSPC, it is free.
+ *
+ * Return -EINVAL if element is invalid, -ENOSPC if dev queue is full
  */
-static bool vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
+static int vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
 {
     unsigned qemu_head;
-    bool ok = vhost_svq_add_split(svq, elem, &qemu_head);
+    unsigned ndescs = elem->in_num + elem->out_num;
+    bool ok;
+
+    if (unlikely(ndescs > vhost_svq_available_slots(svq))) {
+        return -ENOSPC;
+    }
+
+    ok = vhost_svq_add_split(svq, elem, &qemu_head);
     if (unlikely(!ok)) {
         g_free(elem);
-        return false;
+        return -EINVAL;
     }
 
     svq->ring_id_maps[qemu_head] = elem;
     vhost_svq_kick(svq);
-    return true;
+    return 0;
 }
 
 /**
@@ -274,7 +282,7 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
 
         while (true) {
             VirtQueueElement *elem;
-            bool ok;
+            int r;
 
             if (svq->next_guest_avail_elem) {
                 elem = g_steal_pointer(&svq->next_guest_avail_elem);
@@ -286,25 +294,24 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
                 break;
             }
 
-            if (elem->out_num + elem->in_num > vhost_svq_available_slots(svq)) {
-                /*
-                 * This condition is possible since a contiguous buffer in GPA
-                 * does not imply a contiguous buffer in qemu's VA
-                 * scatter-gather segments. If that happens, the buffer exposed
-                 * to the device needs to be a chain of descriptors at this
-                 * moment.
-                 *
-                 * SVQ cannot hold more available buffers if we are here:
-                 * queue the current guest descriptor and ignore further kicks
-                 * until some elements are used.
-                 */
-                svq->next_guest_avail_elem = elem;
-                return;
-            }
-
-            ok = vhost_svq_add(svq, elem);
-            if (unlikely(!ok)) {
-                /* VQ is broken, just return and ignore any other kicks */
+            r = vhost_svq_add(svq, elem);
+            if (unlikely(r != 0)) {
+                if (r == -ENOSPC) {
+                    /*
+                     * This condition is possible since a contiguous buffer in
+                     * GPA does not imply a contiguous buffer in qemu's VA
+                     * scatter-gather segments. If that happens, the buffer
+                     * exposed to the device needs to be a chain of descriptors
+                     * at this moment.
+                     *
+                     * SVQ cannot hold more available buffers if we are here:
+                     * queue the current guest descriptor and ignore kicks
+                     * until some elements are used.
+                     */
+                    svq->next_guest_avail_elem = elem;
+                }
+
+                /* VQ is full or broken, just return and ignore kicks */
                 return;
             }
         }
-- 
2.31.1

[PATCH v3 07/19] vhost: Decouple vhost_svq_add from VirtQueueElement

[Eugenio Pérez]

VirtQueueElement comes from the guest, but we're heading SVQ to be able
to modify the element presented to the device without the guest's
knowledge.

To do so, make SVQ accept sg buffers directly, instead of using
VirtQueueElement.

Add vhost_svq_add_element to maintain element convenience.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.c | 33 ++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index aee9891a67..b005a457c6 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -172,30 +172,31 @@ static bool vhost_svq_vring_write_descs(VhostShadowVirtqueue *svq, hwaddr *sg,
 }
 
 static bool vhost_svq_add_split(VhostShadowVirtqueue *svq,
-                                VirtQueueElement *elem, unsigned *head)
+                                const struct iovec *out_sg, size_t out_num,
+                                const struct iovec *in_sg, size_t in_num,
+                                unsigned *head)
 {
     unsigned avail_idx;
     vring_avail_t *avail = svq->vring.avail;
     bool ok;
-    g_autofree hwaddr *sgs = g_new(hwaddr, MAX(elem->out_num, elem->in_num));
+    g_autofree hwaddr *sgs = g_new(hwaddr, MAX(out_num, in_num));
 
     *head = svq->free_head;
 
     /* We need some descriptors here */
-    if (unlikely(!elem->out_num && !elem->in_num)) {
+    if (unlikely(!out_num && !in_num)) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "Guest provided element with no descriptors");
         return false;
     }
 
-    ok = vhost_svq_vring_write_descs(svq, sgs, elem->out_sg, elem->out_num,
-                                     elem->in_num > 0, false);
+    ok = vhost_svq_vring_write_descs(svq, sgs, out_sg, out_num, in_num > 0,
+                                     false);
     if (unlikely(!ok)) {
         return false;
     }
 
-    ok = vhost_svq_vring_write_descs(svq, sgs, elem->in_sg, elem->in_num, false,
-                                     true);
+    ok = vhost_svq_vring_write_descs(svq, sgs, in_sg, in_num, false, true);
     if (unlikely(!ok)) {
         return false;
     }
@@ -237,17 +238,19 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
  *
  * Return -EINVAL if element is invalid, -ENOSPC if dev queue is full
  */
-static int vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
+static int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
+                          size_t out_num, const struct iovec *in_sg,
+                          size_t in_num, VirtQueueElement *elem)
 {
     unsigned qemu_head;
-    unsigned ndescs = elem->in_num + elem->out_num;
+    unsigned ndescs = in_num + out_num;
     bool ok;
 
     if (unlikely(ndescs > vhost_svq_available_slots(svq))) {
         return -ENOSPC;
     }
 
-    ok = vhost_svq_add_split(svq, elem, &qemu_head);
+    ok = vhost_svq_add_split(svq, out_sg, out_num, in_sg, in_num, &qemu_head);
     if (unlikely(!ok)) {
         g_free(elem);
         return -EINVAL;
@@ -258,6 +261,14 @@ static int vhost_svq_add(VhostShadowVirtqueue *svq, VirtQueueElement *elem)
     return 0;
 }
 
+/* Convenience wrapper to add a guest's element to SVQ */
+static int vhost_svq_add_element(VhostShadowVirtqueue *svq,
+                                 VirtQueueElement *elem)
+{
+    return vhost_svq_add(svq, elem->out_sg, elem->out_num, elem->in_sg,
+                         elem->in_num, elem);
+}
+
 /**
  * Forward available buffers.
  *
@@ -294,7 +305,7 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
                 break;
             }
 
-            r = vhost_svq_add(svq, elem);
+            r = vhost_svq_add_element(svq, elem);
             if (unlikely(r != 0)) {
                 if (r == -ENOSPC) {
                     /*
-- 
2.31.1

[PATCH v3 08/19] vhost: Add SVQDescState

[Eugenio Pérez]

This will allow SVQ to add context to the different queue elements.

This patch only store the actual element, no functional change intended.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |  8 ++++++--
 hw/virtio/vhost-shadow-virtqueue.c | 16 ++++++++--------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index c132c994e9..d646c35054 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -15,6 +15,10 @@
 #include "standard-headers/linux/vhost_types.h"
 #include "hw/virtio/vhost-iova-tree.h"
 
+typedef struct SVQDescState {
+    VirtQueueElement *elem;
+} SVQDescState;
+
 /* Shadow virtqueue to relay notifications */
 typedef struct VhostShadowVirtqueue {
     /* Shadow vring */
@@ -47,8 +51,8 @@ typedef struct VhostShadowVirtqueue {
     /* IOVA mapping */
     VhostIOVATree *iova_tree;
 
-    /* Map for use the guest's descriptors */
-    VirtQueueElement **ring_id_maps;
+    /* SVQ vring descriptors state */
+    SVQDescState *desc_state;
 
     /* Next VirtQueue element that guest made available */
     VirtQueueElement *next_guest_avail_elem;
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index b005a457c6..d12f5afffb 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -256,7 +256,7 @@ static int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
         return -EINVAL;
     }
 
-    svq->ring_id_maps[qemu_head] = elem;
+    svq->desc_state[qemu_head].elem = elem;
     vhost_svq_kick(svq);
     return 0;
 }
@@ -410,21 +410,21 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq,
         return NULL;
     }
 
-    if (unlikely(!svq->ring_id_maps[used_elem.id])) {
+    if (unlikely(!svq->desc_state[used_elem.id].elem)) {
         qemu_log_mask(LOG_GUEST_ERROR,
             "Device %s says index %u is used, but it was not available",
             svq->vdev->name, used_elem.id);
         return NULL;
     }
 
-    num = svq->ring_id_maps[used_elem.id]->in_num +
-          svq->ring_id_maps[used_elem.id]->out_num;
+    num = svq->desc_state[used_elem.id].elem->in_num +
+          svq->desc_state[used_elem.id].elem->out_num;
     last_used_chain = vhost_svq_last_desc_of_chain(svq, num, used_elem.id);
     svq->desc_next[last_used_chain] = svq->free_head;
     svq->free_head = used_elem.id;
 
     *len = used_elem.len;
-    return g_steal_pointer(&svq->ring_id_maps[used_elem.id]);
+    return g_steal_pointer(&svq->desc_state[used_elem.id].elem);
 }
 
 static void vhost_svq_flush(VhostShadowVirtqueue *svq,
@@ -594,7 +594,7 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
     memset(svq->vring.desc, 0, driver_size);
     svq->vring.used = qemu_memalign(qemu_real_host_page_size(), device_size);
     memset(svq->vring.used, 0, device_size);
-    svq->ring_id_maps = g_new0(VirtQueueElement *, svq->vring.num);
+    svq->desc_state = g_new0(SVQDescState, svq->vring.num);
     svq->desc_next = g_new0(uint16_t, svq->vring.num);
     for (unsigned i = 0; i < svq->vring.num - 1; i++) {
         svq->desc_next[i] = cpu_to_le16(i + 1);
@@ -619,7 +619,7 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
 
     for (unsigned i = 0; i < svq->vring.num; ++i) {
         g_autofree VirtQueueElement *elem = NULL;
-        elem = g_steal_pointer(&svq->ring_id_maps[i]);
+        elem = g_steal_pointer(&svq->desc_state[i].elem);
         if (elem) {
             virtqueue_detach_element(svq->vq, elem, 0);
         }
@@ -631,7 +631,7 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
     }
     svq->vq = NULL;
     g_free(svq->desc_next);
-    g_free(svq->ring_id_maps);
+    g_free(svq->desc_state);
     qemu_vfree(svq->vring.desc);
     qemu_vfree(svq->vring.used);
 }
-- 
2.31.1

[PATCH v3 09/19] vhost: Track number of descs in SVQDescState

[Eugenio Pérez]

A guest's buffer continuos on GPA may need multiple descriptors on
qemu's VA, so SVQ should track its length sepparatedly.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h | 6 ++++++
 hw/virtio/vhost-shadow-virtqueue.c | 4 ++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index d646c35054..5c7e7cbab6 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -17,6 +17,12 @@
 
 typedef struct SVQDescState {
     VirtQueueElement *elem;
+
+    /*
+     * Number of descriptors exposed to the device. May or may not match
+     * guest's
+     */
+    unsigned int ndescs;
 } SVQDescState;
 
 /* Shadow virtqueue to relay notifications */
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index d12f5afffb..ae5bd6efa8 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -257,6 +257,7 @@ static int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
     }
 
     svq->desc_state[qemu_head].elem = elem;
+    svq->desc_state[qemu_head].ndescs = ndescs;
     vhost_svq_kick(svq);
     return 0;
 }
@@ -417,8 +418,7 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq,
         return NULL;
     }
 
-    num = svq->desc_state[used_elem.id].elem->in_num +
-          svq->desc_state[used_elem.id].elem->out_num;
+    num = svq->desc_state[used_elem.id].ndescs;
     last_used_chain = vhost_svq_last_desc_of_chain(svq, num, used_elem.id);
     svq->desc_next[last_used_chain] = svq->free_head;
     svq->free_head = used_elem.id;
-- 
2.31.1

[PATCH v3 10/19] vhost: add vhost_svq_push_elem

[Eugenio Pérez]

This function allows external SVQ users to return guest's available
buffers.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |  3 +++
 hw/virtio/vhost-shadow-virtqueue.c | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index 5c7e7cbab6..d9fc1f1799 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -84,6 +84,9 @@ typedef struct VhostShadowVirtqueue {
 
 bool vhost_svq_valid_features(uint64_t features, Error **errp);
 
+void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
+                         const VirtQueueElement *elem, uint32_t len);
+
 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
 void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
 void vhost_svq_get_vring_addr(const VhostShadowVirtqueue *svq,
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index ae5bd6efa8..b377e125e7 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -427,6 +427,22 @@ static VirtQueueElement *vhost_svq_get_buf(VhostShadowVirtqueue *svq,
     return g_steal_pointer(&svq->desc_state[used_elem.id].elem);
 }
 
+/**
+ * Push an element to SVQ, returning it to the guest.
+ */
+void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
+                         const VirtQueueElement *elem, uint32_t len)
+{
+    virtqueue_push(svq->vq, elem, len);
+    if (svq->next_guest_avail_elem) {
+        /*
+         * Avail ring was full when vhost_svq_flush was called, so it's a
+         * good moment to make more descriptors available if possible.
+         */
+        vhost_handle_guest_kick(svq);
+    }
+}
+
 static void vhost_svq_flush(VhostShadowVirtqueue *svq,
                             bool check_for_avail_queue)
 {
-- 
2.31.1

[PATCH v3 11/19] vhost: Expose vhost_svq_add

[Eugenio Pérez]

This allows external parts of SVQ to forward custom buffers to the
device.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h | 3 +++
 hw/virtio/vhost-shadow-virtqueue.c | 6 +++---
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index d9fc1f1799..dd78f4bec2 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -86,6 +86,9 @@ bool vhost_svq_valid_features(uint64_t features, Error **errp);
 
 void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
                          const VirtQueueElement *elem, uint32_t len);
+int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
+                  size_t out_num, const struct iovec *in_sg, size_t in_num,
+                  VirtQueueElement *elem);
 
 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
 void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index b377e125e7..406a823c81 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -238,9 +238,9 @@ static void vhost_svq_kick(VhostShadowVirtqueue *svq)
  *
  * Return -EINVAL if element is invalid, -ENOSPC if dev queue is full
  */
-static int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
-                          size_t out_num, const struct iovec *in_sg,
-                          size_t in_num, VirtQueueElement *elem)
+int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
+                  size_t out_num, const struct iovec *in_sg, size_t in_num,
+                  VirtQueueElement *elem)
 {
     unsigned qemu_head;
     unsigned ndescs = in_num + out_num;
-- 
2.31.1

[PATCH v3 12/19] vhost: add vhost_svq_poll

[Eugenio Pérez]

It allows the Shadow Control VirtQueue to wait for the device to use the
available buffers.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h |  1 +
 hw/virtio/vhost-shadow-virtqueue.c | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index dd78f4bec2..cf442f7dea 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -89,6 +89,7 @@ void vhost_svq_push_elem(VhostShadowVirtqueue *svq,
 int vhost_svq_add(VhostShadowVirtqueue *svq, const struct iovec *out_sg,
                   size_t out_num, const struct iovec *in_sg, size_t in_num,
                   VirtQueueElement *elem);
+size_t vhost_svq_poll(VhostShadowVirtqueue *svq);
 
 void vhost_svq_set_svq_kick_fd(VhostShadowVirtqueue *svq, int svq_kick_fd);
 void vhost_svq_set_svq_call_fd(VhostShadowVirtqueue *svq, int call_fd);
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 406a823c81..1c54a03e17 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -484,6 +484,28 @@ static void vhost_svq_flush(VhostShadowVirtqueue *svq,
     } while (!vhost_svq_enable_notification(svq));
 }
 
+/**
+ * Poll the SVQ for one device used buffer.
+ *
+ * This function race with main event loop SVQ polling, so extra
+ * synchronization is needed.
+ *
+ * Return the length written by the device.
+ */
+size_t vhost_svq_poll(VhostShadowVirtqueue *svq)
+{
+    do {
+        uint32_t len;
+        VirtQueueElement *elem = vhost_svq_get_buf(svq, &len);
+        if (elem) {
+            return len;
+        }
+
+        /* Make sure we read new used_idx */
+        smp_rmb();
+    } while (true);
+}
+
 /**
  * Forward used buffers.
  *
-- 
2.31.1

[PATCH v3 13/19] vhost: Add svq avail_handler callback

[Eugenio Pérez]

This allows external handlers to be aware of new buffers that the guest
places in the virtqueue.

When this callback is defined the ownership of the guest's virtqueue
element is transferred to the callback. This means that if the user
wants to forward the descriptor it needs to manually inject it. The
callback is also free to process the command by itself and use the
element with svq_push.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 hw/virtio/vhost-shadow-virtqueue.h | 31 +++++++++++++++++++++++++++++-
 hw/virtio/vhost-shadow-virtqueue.c | 14 ++++++++++++--
 hw/virtio/vhost-vdpa.c             |  3 ++-
 3 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/vhost-shadow-virtqueue.h b/hw/virtio/vhost-shadow-virtqueue.h
index cf442f7dea..d04c34a589 100644
--- a/hw/virtio/vhost-shadow-virtqueue.h
+++ b/hw/virtio/vhost-shadow-virtqueue.h
@@ -25,6 +25,27 @@ typedef struct SVQDescState {
     unsigned int ndescs;
 } SVQDescState;
 
+typedef struct VhostShadowVirtqueue VhostShadowVirtqueue;
+
+/**
+ * Callback to handle an avail buffer.
+ *
+ * @svq:  Shadow virtqueue
+ * @elem:  Element placed in the queue by the guest
+ * @vq_callback_opaque:  Opaque
+ *
+ * Returns 0 if the vq is running as expected.
+ *
+ * Note that ownership of elem is transferred to the callback.
+ */
+typedef int (*VirtQueueAvailCallback)(VhostShadowVirtqueue *svq,
+                                      VirtQueueElement *elem,
+                                      void *vq_callback_opaque);
+
+typedef struct VhostShadowVirtqueueOps {
+    VirtQueueAvailCallback avail_handler;
+} VhostShadowVirtqueueOps;
+
 /* Shadow virtqueue to relay notifications */
 typedef struct VhostShadowVirtqueue {
     /* Shadow vring */
@@ -69,6 +90,12 @@ typedef struct VhostShadowVirtqueue {
      */
     uint16_t *desc_next;
 
+    /* Caller callbacks */
+    const VhostShadowVirtqueueOps *ops;
+
+    /* Caller callbacks opaque */
+    void *ops_opaque;
+
     /* Next head to expose to the device */
     uint16_t shadow_avail_idx;
 
@@ -102,7 +129,9 @@ void vhost_svq_start(VhostShadowVirtqueue *svq, VirtIODevice *vdev,
                      VirtQueue *vq);
 void vhost_svq_stop(VhostShadowVirtqueue *svq);
 
-VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree);
+VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
+                                    const VhostShadowVirtqueueOps *ops,
+                                    void *ops_opaque);
 
 void vhost_svq_free(gpointer vq);
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(VhostShadowVirtqueue, vhost_svq_free);
diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c
index 1c54a03e17..a21b0b1bf6 100644
--- a/hw/virtio/vhost-shadow-virtqueue.c
+++ b/hw/virtio/vhost-shadow-virtqueue.c
@@ -306,7 +306,11 @@ static void vhost_handle_guest_kick(VhostShadowVirtqueue *svq)
                 break;
             }
 
-            r = vhost_svq_add_element(svq, elem);
+            if (svq->ops) {
+                r = svq->ops->avail_handler(svq, elem, svq->ops_opaque);
+            } else {
+                r = vhost_svq_add_element(svq, elem);
+            }
             if (unlikely(r != 0)) {
                 if (r == -ENOSPC) {
                     /*
@@ -679,12 +683,16 @@ void vhost_svq_stop(VhostShadowVirtqueue *svq)
  * shadow methods and file descriptors.
  *
  * @iova_tree: Tree to perform descriptors translations
+ * @ops: SVQ owner callbacks
+ * @ops_opaque: ops opaque pointer
  *
  * Returns the new virtqueue or NULL.
  *
  * In case of error, reason is reported through error_report.
  */
-VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree)
+VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree,
+                                    const VhostShadowVirtqueueOps *ops,
+                                    void *ops_opaque)
 {
     g_autofree VhostShadowVirtqueue *svq = g_new0(VhostShadowVirtqueue, 1);
     int r;
@@ -706,6 +714,8 @@ VhostShadowVirtqueue *vhost_svq_new(VhostIOVATree *iova_tree)
     event_notifier_init_fd(&svq->svq_kick, VHOST_FILE_UNBIND);
     event_notifier_set_handler(&svq->hdev_call, vhost_svq_handle_call);
     svq->iova_tree = iova_tree;
+    svq->ops = ops;
+    svq->ops_opaque = ops_opaque;
     return g_steal_pointer(&svq);
 
 err_init_hdev_call:
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 66f054a12c..0b13e98471 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -418,8 +418,9 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
 
     shadow_vqs = g_ptr_array_new_full(hdev->nvqs, vhost_svq_free);
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
-        g_autoptr(VhostShadowVirtqueue) svq = vhost_svq_new(v->iova_tree);
+        g_autoptr(VhostShadowVirtqueue) svq;
 
+        svq = vhost_svq_new(v->iova_tree, NULL, NULL);
         if (unlikely(!svq)) {
             error_setg(errp, "Cannot create svq %u", n);
             return -1;
-- 
2.31.1

[PATCH v3 14/19] vdpa: Export vhost_vdpa_dma_map and unmap calls

[Eugenio Pérez]

Shadow CVQ will copy buffers on qemu VA, so we avoid TOCTOU attacks from
the guest that could set a different state in qemu device model and vdpa
device.

To do so, it needs to be able to map these new buffers to the device.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h | 4 ++++
 hw/virtio/vhost-vdpa.c         | 7 +++----
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index a29dbb3f53..7214eb47dc 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -39,4 +39,8 @@ typedef struct vhost_vdpa {
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
 
+int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,
+                       void *vaddr, bool readonly);
+int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova, hwaddr size);
+
 #endif
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 0b13e98471..96997210be 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -71,8 +71,8 @@ static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section,
     return false;
 }
 
-static int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,
-                              void *vaddr, bool readonly)
+int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,
+                       void *vaddr, bool readonly)
 {
     struct vhost_msg_v2 msg = {};
     int fd = v->device_fd;
@@ -97,8 +97,7 @@ static int vhost_vdpa_dma_map(struct vhost_vdpa *v, hwaddr iova, hwaddr size,
     return ret;
 }
 
-static int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova,
-                                hwaddr size)
+int vhost_vdpa_dma_unmap(struct vhost_vdpa *v, hwaddr iova, hwaddr size)
 {
     struct vhost_msg_v2 msg = {};
     int fd = v->device_fd;
-- 
2.31.1

[PATCH v3 15/19] vdpa: manual forward CVQ buffers

[Eugenio Pérez]

Do a simple forwarding of CVQ buffers, the same work SVQ could do but
through callbacks. No functional change intended.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  3 ++
 hw/virtio/vhost-vdpa.c         |  3 +-
 net/vhost-vdpa.c               | 58 ++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 7214eb47dc..1111d85643 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -15,6 +15,7 @@
 #include <gmodule.h>
 
 #include "hw/virtio/vhost-iova-tree.h"
+#include "hw/virtio/vhost-shadow-virtqueue.h"
 #include "hw/virtio/virtio.h"
 #include "standard-headers/linux/vhost_types.h"
 
@@ -35,6 +36,8 @@ typedef struct vhost_vdpa {
     /* IOVA mapping used by the Shadow Virtqueue */
     VhostIOVATree *iova_tree;
     GPtrArray *shadow_vqs;
+    const VhostShadowVirtqueueOps *shadow_vq_ops;
+    void *shadow_vq_ops_opaque;
     struct vhost_dev *dev;
     VhostVDPAHostNotifier notifier[VIRTIO_QUEUE_MAX];
 } VhostVDPA;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 96997210be..beaaa7049a 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -419,7 +419,8 @@ static int vhost_vdpa_init_svq(struct vhost_dev *hdev, struct vhost_vdpa *v,
     for (unsigned n = 0; n < hdev->nvqs; ++n) {
         g_autoptr(VhostShadowVirtqueue) svq;
 
-        svq = vhost_svq_new(v->iova_tree, NULL, NULL);
+        svq = vhost_svq_new(v->iova_tree, v->shadow_vq_ops,
+                            v->shadow_vq_ops_opaque);
         if (unlikely(!svq)) {
             error_setg(errp, "Cannot create svq %u", n);
             return -1;
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index df1e69ee72..2e3b6b10d8 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -11,11 +11,14 @@
 
 #include "qemu/osdep.h"
 #include "clients.h"
+#include "hw/virtio/virtio-net.h"
 #include "net/vhost_net.h"
 #include "net/vhost-vdpa.h"
 #include "hw/virtio/vhost-vdpa.h"
 #include "qemu/config-file.h"
 #include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/memalign.h"
 #include "qemu/option.h"
 #include "qapi/error.h"
 #include <linux/vhost.h>
@@ -187,6 +190,57 @@ static NetClientInfo net_vhost_vdpa_info = {
         .check_peer_type = vhost_vdpa_check_peer_type,
 };
 
+/**
+ * Forward buffer for the moment.
+ */
+static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
+                                            VirtQueueElement *elem,
+                                            void *opaque)
+{
+    unsigned int n = elem->out_num + elem->in_num;
+    g_autofree struct iovec *dev_buffers = g_new(struct iovec, n);
+    size_t in_len, dev_written;
+    virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+    int r;
+
+    memcpy(dev_buffers, elem->out_sg, elem->out_num);
+    memcpy(dev_buffers + elem->out_num, elem->in_sg, elem->in_num);
+
+    r = vhost_svq_add(svq, &dev_buffers[0], elem->out_num, &dev_buffers[1],
+                      elem->in_num, elem);
+    if (unlikely(r != 0)) {
+        if (unlikely(r == -ENOSPC)) {
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",
+                          __func__);
+        }
+        goto out;
+    }
+
+    /*
+     * We can poll here since we've had BQL from the time we sent the
+     * descriptor. Also, we need to take the answer before SVQ pulls by itself,
+     * when BQL is released
+     */
+    dev_written = vhost_svq_poll(svq);
+    if (unlikely(dev_written < sizeof(status))) {
+        error_report("Insufficient written data (%zu)", dev_written);
+    }
+
+out:
+    in_len = iov_from_buf(elem->in_sg, elem->in_num, 0, &status,
+                          sizeof(status));
+    if (unlikely(in_len < sizeof(status))) {
+        error_report("Bad device CVQ written length");
+    }
+    vhost_svq_push_elem(svq, elem, MIN(in_len, sizeof(status)));
+    g_free(elem);
+    return r;
+}
+
+static const VhostShadowVirtqueueOps vhost_vdpa_net_svq_ops = {
+    .avail_handler = vhost_vdpa_net_handle_ctrl_avail,
+};
+
 static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
                                            const char *device,
                                            const char *name,
@@ -211,6 +265,10 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
+    if (!is_datapath) {
+        s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
+        s->vhost_vdpa.shadow_vq_ops_opaque = s;
+    }
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
         qemu_del_net_client(nc);
-- 
2.31.1

[PATCH v3 16/19] vdpa: Buffer CVQ support on shadow virtqueue

[Eugenio Pérez]

Introduce the control virtqueue support for vDPA shadow virtqueue. This
is needed for advanced networking features like rx filtering.

Virtio-net control VQ copies the descriptors to qemu's VA, so we avoid
TOCTOU with the guest's or device's memory every time there is a device
model change.  Otherwise, the guest could change the memory content in
the time between qemu and the device read it.

To demonstrate command handling, VIRTIO_NET_F_CTRL_MACADDR is
implemented.  If the virtio-net driver changes MAC the virtio-net device
model will be updated with the new one, and a rx filtering change event
will be raised.

More cvq commands could be added here straightforwardly but they have
not been tested.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 211 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 204 insertions(+), 7 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 2e3b6b10d8..3915b148c4 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -33,6 +33,9 @@ typedef struct VhostVDPAState {
     NetClientState nc;
     struct vhost_vdpa vhost_vdpa;
     VHostNetState *vhost_net;
+
+    /* Control commands shadow buffers */
+    void *cvq_cmd_out_buffer, *cvq_cmd_in_buffer;
     bool started;
 } VhostVDPAState;
 
@@ -131,6 +134,8 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
 
+    qemu_vfree(s->cvq_cmd_out_buffer);
+    qemu_vfree(s->cvq_cmd_in_buffer);
     if (s->vhost_net) {
         vhost_net_cleanup(s->vhost_net);
         g_free(s->vhost_net);
@@ -190,24 +195,191 @@ static NetClientInfo net_vhost_vdpa_info = {
         .check_peer_type = vhost_vdpa_check_peer_type,
 };
 
+static void vhost_vdpa_cvq_unmap_buf(struct vhost_vdpa *v, void *addr)
+{
+    VhostIOVATree *tree = v->iova_tree;
+    DMAMap needle = {
+        /*
+         * No need to specify size or to look for more translations since
+         * this contiguous chunk was allocated by us.
+         */
+        .translated_addr = (hwaddr)(uintptr_t)addr,
+    };
+    const DMAMap *map = vhost_iova_tree_find_iova(tree, &needle);
+    int r;
+
+    if (unlikely(!map)) {
+        error_report("Cannot locate expected map");
+        return;
+    }
+
+    r = vhost_vdpa_dma_unmap(v, map->iova, map->size + 1);
+    if (unlikely(r != 0)) {
+        error_report("Device cannot unmap: %s(%d)", g_strerror(r), r);
+    }
+
+    vhost_iova_tree_remove(tree, map);
+}
+
+static size_t vhost_vdpa_net_cvq_cmd_len(void)
+{
+    /*
+     * MAC_TABLE_SET is the ctrl command that produces the longer out buffer.
+     * In buffer is always 1 byte, so it should fit here
+     */
+    return sizeof(struct virtio_net_ctrl_hdr) +
+           2 * sizeof(struct virtio_net_ctrl_mac) +
+           MAC_TABLE_ENTRIES * ETH_ALEN;
+}
+
+static size_t vhost_vdpa_net_cvq_cmd_page_len(void)
+{
+    return ROUND_UP(vhost_vdpa_net_cvq_cmd_len(), qemu_real_host_page_size());
+}
+
+/** Copy and map a guest buffer. */
+static bool vhost_vdpa_cvq_map_buf(struct vhost_vdpa *v,
+                                   const struct iovec *out_data,
+                                   size_t out_num, size_t data_len, void *buf,
+                                   size_t *written, bool write)
+{
+    DMAMap map = {};
+    int r;
+
+    if (unlikely(!data_len)) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid legnth of %s buffer\n",
+                      __func__, write ? "in" : "out");
+        return false;
+    }
+
+    *written = iov_to_buf(out_data, out_num, 0, buf, data_len);
+    map.translated_addr = (hwaddr)(uintptr_t)buf;
+    map.size = vhost_vdpa_net_cvq_cmd_page_len() - 1;
+    map.perm = write ? IOMMU_RW : IOMMU_RO,
+    r = vhost_iova_tree_map_alloc(v->iova_tree, &map);
+    if (unlikely(r != IOVA_OK)) {
+        error_report("Cannot map injected element");
+        return false;
+    }
+
+    r = vhost_vdpa_dma_map(v, map.iova, vhost_vdpa_net_cvq_cmd_page_len(), buf,
+                           !write);
+    if (unlikely(r < 0)) {
+        goto dma_map_err;
+    }
+
+    return true;
+
+dma_map_err:
+    vhost_iova_tree_remove(v->iova_tree, &map);
+    return false;
+}
+
 /**
- * Forward buffer for the moment.
+ * Copy the guest element into a dedicated buffer suitable to be sent to NIC
+ *
+ * @iov: [0] is the out buffer, [1] is the in one
+ */
+static bool vhost_vdpa_net_cvq_map_elem(VhostVDPAState *s,
+                                        VirtQueueElement *elem,
+                                        struct iovec *iov)
+{
+    size_t in_copied;
+    bool ok;
+
+    iov[0].iov_base = s->cvq_cmd_out_buffer;
+    ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, elem->out_sg, elem->out_num,
+                                vhost_vdpa_net_cvq_cmd_len(), iov[0].iov_base,
+                                &iov[0].iov_len, false);
+    if (unlikely(!ok)) {
+        return false;
+    }
+
+    iov[1].iov_base = s->cvq_cmd_in_buffer;
+    ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, NULL, 0,
+                                sizeof(virtio_net_ctrl_ack), iov[1].iov_base,
+                                &in_copied, true);
+    if (unlikely(!ok)) {
+        vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
+        return false;
+    }
+
+    iov[1].iov_len = sizeof(virtio_net_ctrl_ack);
+    return true;
+}
+
+/**
+ * Do not forward commands not supported by SVQ. Otherwise, the device could
+ * accept it and qemu would not know how to update the device model.
+ */
+static bool vhost_vdpa_net_cvq_validate_cmd(const struct iovec *out,
+                                            size_t out_num)
+{
+    struct virtio_net_ctrl_hdr ctrl;
+    size_t n;
+
+    n = iov_to_buf(out, out_num, 0, &ctrl, sizeof(ctrl));
+    if (unlikely(n < sizeof(ctrl))) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: invalid legnth of out buffer %zu\n", __func__, n);
+        return false;
+    }
+
+    switch (ctrl.class) {
+    case VIRTIO_NET_CTRL_MAC:
+        switch (ctrl.cmd) {
+        case VIRTIO_NET_CTRL_MAC_ADDR_SET:
+            return true;
+        default:
+            qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid mac cmd %u\n",
+                          __func__, ctrl.cmd);
+        };
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid control class %u\n",
+                      __func__, ctrl.class);
+    };
+
+    return false;
+}
+
+/**
+ * Validate and copy control virtqueue commands.
+ *
+ * Following QEMU guidelines, we offer a copy of the buffers to the device to
+ * prevent TOCTOU bugs.
  */
 static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
                                             VirtQueueElement *elem,
                                             void *opaque)
 {
-    unsigned int n = elem->out_num + elem->in_num;
-    g_autofree struct iovec *dev_buffers = g_new(struct iovec, n);
+    VhostVDPAState *s = opaque;
     size_t in_len, dev_written;
     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
+    /* out and in buffers sent to the device */
+    struct iovec dev_buffers[2] = {
+        { .iov_base = s->cvq_cmd_out_buffer },
+        { .iov_base = s->cvq_cmd_in_buffer },
+    };
+    /* in buffer used for device model */
+    const struct iovec in = {
+        .iov_base = &status,
+        .iov_len = sizeof(status),
+    };
     int r;
+    bool ok;
 
-    memcpy(dev_buffers, elem->out_sg, elem->out_num);
-    memcpy(dev_buffers + elem->out_num, elem->in_sg, elem->in_num);
+    ok = vhost_vdpa_net_cvq_map_elem(s, elem, dev_buffers);
+    if (unlikely(!ok)) {
+        goto out;
+    }
 
-    r = vhost_svq_add(svq, &dev_buffers[0], elem->out_num, &dev_buffers[1],
-                      elem->in_num, elem);
+    ok = vhost_vdpa_net_cvq_validate_cmd(&dev_buffers[0], 1);
+    if (unlikely(!ok)) {
+        goto out;
+    }
+
+    r = vhost_svq_add(svq, &dev_buffers[0], 1, &dev_buffers[1], 1, elem);
     if (unlikely(r != 0)) {
         if (unlikely(r == -ENOSPC)) {
             qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",
@@ -224,6 +396,18 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,
     dev_written = vhost_svq_poll(svq);
     if (unlikely(dev_written < sizeof(status))) {
         error_report("Insufficient written data (%zu)", dev_written);
+        goto out;
+    }
+
+    memcpy(&status, dev_buffers[1].iov_base, sizeof(status));
+    if (status != VIRTIO_NET_OK) {
+        goto out;
+    }
+
+    status = VIRTIO_NET_ERR;
+    virtio_net_handle_ctrl_iov(svq->vdev, &in, 1, dev_buffers, 1);
+    if (status != VIRTIO_NET_OK) {
+        error_report("Bad CVQ processing in model");
     }
 
 out:
@@ -234,6 +418,12 @@ out:
     }
     vhost_svq_push_elem(svq, elem, MIN(in_len, sizeof(status)));
     g_free(elem);
+    if (dev_buffers[0].iov_base) {
+        vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, dev_buffers[0].iov_base);
+    }
+    if (dev_buffers[1].iov_base) {
+        vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, dev_buffers[1].iov_base);
+    }
     return r;
 }
 
@@ -266,6 +456,13 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
     if (!is_datapath) {
+        s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(),
+                                            vhost_vdpa_net_cvq_cmd_page_len());
+        memset(s->cvq_cmd_out_buffer, 0, vhost_vdpa_net_cvq_cmd_page_len());
+        s->cvq_cmd_in_buffer = qemu_memalign(qemu_real_host_page_size(),
+                                            vhost_vdpa_net_cvq_cmd_page_len());
+        memset(s->cvq_cmd_in_buffer, 0, vhost_vdpa_net_cvq_cmd_page_len());
+
         s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
         s->vhost_vdpa.shadow_vq_ops_opaque = s;
     }
-- 
2.31.1

[PATCH v3 17/19] vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs

[Eugenio Pérez]

To know the device features is needed for CVQ SVQ, so SVQ knows if it
can handle all commands or not. Extract from
vhost_vdpa_get_max_queue_pairs so we can reuse it.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
---
 net/vhost-vdpa.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 3915b148c4..0afa60bb51 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -474,20 +474,24 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
     return nc;
 }
 
-static int vhost_vdpa_get_max_queue_pairs(int fd, int *has_cvq, Error **errp)
+static int vhost_vdpa_get_features(int fd, uint64_t *features, Error **errp)
+{
+    int ret = ioctl(fd, VHOST_GET_FEATURES, features);
+    if (unlikely(ret < 0)) {
+        error_setg_errno(errp, errno,
+                         "Fail to query features from vhost-vDPA device");
+    }
+    return ret;
+}
+
+static int vhost_vdpa_get_max_queue_pairs(int fd, uint64_t features,
+                                          int *has_cvq, Error **errp)
 {
     unsigned long config_size = offsetof(struct vhost_vdpa_config, buf);
     g_autofree struct vhost_vdpa_config *config = NULL;
     __virtio16 *max_queue_pairs;
-    uint64_t features;
     int ret;
 
-    ret = ioctl(fd, VHOST_GET_FEATURES, &features);
-    if (ret) {
-        error_setg(errp, "Fail to query features from vhost-vDPA device");
-        return ret;
-    }
-
     if (features & (1 << VIRTIO_NET_F_CTRL_VQ)) {
         *has_cvq = 1;
     } else {
@@ -517,10 +521,11 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
                         NetClientState *peer, Error **errp)
 {
     const NetdevVhostVDPAOptions *opts;
+    uint64_t features;
     int vdpa_device_fd;
     g_autofree NetClientState **ncs = NULL;
     NetClientState *nc;
-    int queue_pairs, i, has_cvq = 0;
+    int queue_pairs, r, i, has_cvq = 0;
 
     assert(netdev->type == NET_CLIENT_DRIVER_VHOST_VDPA);
     opts = &netdev->u.vhost_vdpa;
@@ -534,7 +539,12 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char *name,
         return -errno;
     }
 
-    queue_pairs = vhost_vdpa_get_max_queue_pairs(vdpa_device_fd,
+    r = vhost_vdpa_get_features(vdpa_device_fd, &features, errp);
+    if (unlikely(r < 0)) {
+        return r;
+    }
+
+    queue_pairs = vhost_vdpa_get_max_queue_pairs(vdpa_device_fd, features,
                                                  &has_cvq, errp);
     if (queue_pairs < 0) {
         qemu_close(vdpa_device_fd);
-- 
2.31.1

[PATCH v3 18/19] vdpa: Add device migration blocker

[Eugenio Pérez]

Since the vhost-vdpa device is exposing _F_LOG, adding a migration blocker if
it uses CVQ.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 include/hw/virtio/vhost-vdpa.h |  1 +
 hw/virtio/vhost-vdpa.c         | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/hw/virtio/vhost-vdpa.h b/include/hw/virtio/vhost-vdpa.h
index 1111d85643..d10a89303e 100644
--- a/include/hw/virtio/vhost-vdpa.h
+++ b/include/hw/virtio/vhost-vdpa.h
@@ -35,6 +35,7 @@ typedef struct vhost_vdpa {
     bool shadow_vqs_enabled;
     /* IOVA mapping used by the Shadow Virtqueue */
     VhostIOVATree *iova_tree;
+    Error *migration_blocker;
     GPtrArray *shadow_vqs;
     const VhostShadowVirtqueueOps *shadow_vq_ops;
     void *shadow_vq_ops_opaque;
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index beaaa7049a..795ed5a049 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -20,6 +20,7 @@
 #include "hw/virtio/vhost-shadow-virtqueue.h"
 #include "hw/virtio/vhost-vdpa.h"
 #include "exec/address-spaces.h"
+#include "migration/blocker.h"
 #include "qemu/cutils.h"
 #include "qemu/main-loop.h"
 #include "cpu.h"
@@ -1022,6 +1023,13 @@ static bool vhost_vdpa_svqs_start(struct vhost_dev *dev)
         return true;
     }
 
+    if (v->migration_blocker) {
+        int r = migrate_add_blocker(v->migration_blocker, &err);
+        if (unlikely(r < 0)) {
+            goto err_migration_blocker;
+        }
+    }
+
     for (i = 0; i < v->shadow_vqs->len; ++i) {
         VirtQueue *vq = virtio_get_queue(dev->vdev, dev->vq_index + i);
         VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, i);
@@ -1064,6 +1072,9 @@ err:
         vhost_svq_stop(svq);
     }
 
+err_migration_blocker:
+    error_reportf_err(err, "Cannot setup SVQ %u: ", i);
+
     return false;
 }
 
@@ -1083,6 +1094,9 @@ static bool vhost_vdpa_svqs_stop(struct vhost_dev *dev)
         }
     }
 
+    if (v->migration_blocker) {
+        migrate_del_blocker(v->migration_blocker);
+    }
     return true;
 }
 
-- 
2.31.1

[PATCH v3 19/19] vdpa: Add x-svq to NetdevVhostVDPAOptions

[Eugenio Pérez]

Finally offering the possibility to enable SVQ from the command line.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
---
 qapi/net.json    |  9 +++++-
 net/vhost-vdpa.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/qapi/net.json b/qapi/net.json
index 9af11e9a3b..75ba2cb989 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -445,12 +445,19 @@
 # @queues: number of queues to be created for multiqueue vhost-vdpa
 #          (default: 1)
 #
+# @x-svq: Start device with (experimental) shadow virtqueue. (Since 7.1)
+#         (default: false)
+#
+# Features:
+# @unstable: Member @x-svq is experimental.
+#
 # Since: 5.1
 ##
 { 'struct': 'NetdevVhostVDPAOptions',
   'data': {
     '*vhostdev':     'str',
-    '*queues':       'int' } }
+    '*queues':       'int',
+    '*x-svq':        {'type': 'bool', 'features' : [ 'unstable'] } } }
 
 ##
 # @NetdevVmnetHostOptions:
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 0afa60bb51..986e6414b4 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -75,6 +75,28 @@ const int vdpa_feature_bits[] = {
     VHOST_INVALID_FEATURE_BIT
 };
 
+/** Supported device specific feature bits with SVQ */
+static const uint64_t vdpa_svq_device_features =
+    BIT_ULL(VIRTIO_NET_F_CSUM) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_CSUM) |
+    BIT_ULL(VIRTIO_NET_F_MTU) |
+    BIT_ULL(VIRTIO_NET_F_MAC) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_TSO4) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_TSO6) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_ECN) |
+    BIT_ULL(VIRTIO_NET_F_GUEST_UFO) |
+    BIT_ULL(VIRTIO_NET_F_HOST_TSO4) |
+    BIT_ULL(VIRTIO_NET_F_HOST_TSO6) |
+    BIT_ULL(VIRTIO_NET_F_HOST_ECN) |
+    BIT_ULL(VIRTIO_NET_F_HOST_UFO) |
+    BIT_ULL(VIRTIO_NET_F_MRG_RXBUF) |
+    BIT_ULL(VIRTIO_NET_F_STATUS) |
+    BIT_ULL(VIRTIO_NET_F_CTRL_VQ) |
+    BIT_ULL(VIRTIO_F_ANY_LAYOUT) |
+    BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR) |
+    BIT_ULL(VIRTIO_NET_F_RSC_EXT) |
+    BIT_ULL(VIRTIO_NET_F_STANDBY);
+
 VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
@@ -133,9 +155,13 @@ 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->cvq_cmd_in_buffer);
+    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);
@@ -437,7 +463,9 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
                                            int vdpa_device_fd,
                                            int queue_pair_index,
                                            int nvqs,
-                                           bool is_datapath)
+                                           bool is_datapath,
+                                           bool svq,
+                                           VhostIOVATree *iova_tree)
 {
     NetClientState *nc = NULL;
     VhostVDPAState *s;
@@ -455,6 +483,8 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
+    s->vhost_vdpa.shadow_vqs_enabled = 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());
@@ -465,6 +495,8 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
         s->vhost_vdpa.shadow_vq_ops = &vhost_vdpa_net_svq_ops;
         s->vhost_vdpa.shadow_vq_ops_opaque = s;
+        error_setg(&s->vhost_vdpa.migration_blocker,
+                   "Migration disabled: vhost-vdpa uses CVQ.");
     }
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
@@ -474,6 +506,14 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
     return nc;
 }
 
+static int vhost_vdpa_get_iova_range(int fd,
+                                     struct vhost_vdpa_iova_range *iova_range)
+{
+    int ret = ioctl(fd, VHOST_VDPA_GET_IOVA_RANGE, iova_range);
+
+    return ret < 0 ? -errno : 0;
+}
+
 static int vhost_vdpa_get_features(int fd, uint64_t *features, Error **errp)
 {
     int ret = ioctl(fd, VHOST_GET_FEATURES, features);
@@ -524,6 +564,7 @@ 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;
     NetClientState *nc;
     int queue_pairs, r, i, has_cvq = 0;
 
@@ -551,22 +592,45 @@ 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;
+
+        uint64_t invalid_dev_features =
+            features & ~vdpa_svq_device_features &
+            /* Transport are all accepted at this point */
+            ~MAKE_64BIT_MASK(VIRTIO_TRANSPORT_F_START,
+                             VIRTIO_TRANSPORT_F_END - VIRTIO_TRANSPORT_F_START);
+
+        if (invalid_dev_features) {
+            error_setg(errp, "vdpa svq does not work with features 0x%" PRIx64,
+                       invalid_dev_features);
+            goto err_svq;
+        }
+
+        vhost_vdpa_get_iova_range(vdpa_device_fd, &iova_range);
+        iova_tree = vhost_iova_tree_new(iova_range.first, iova_range.last);
+    }
+
     ncs = g_malloc0(sizeof(*ncs) * queue_pairs);
 
     for (i = 0; i < queue_pairs; i++) {
         ncs[i] = net_vhost_vdpa_init(peer, TYPE_VHOST_VDPA, name,
-                                     vdpa_device_fd, i, 2, true);
+                                     vdpa_device_fd, i, 2, true, 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, false,
+                                 opts->x_svq, iova_tree);
         if (!nc)
             goto err;
     }
 
+    /* iova_tree ownership belongs to last NetClientState */
+    g_steal_pointer(&iova_tree);
     return 0;
 
 err:
@@ -575,6 +639,8 @@ err:
             qemu_del_net_client(ncs[i]);
         }
     }
+
+err_svq:
     qemu_close(vdpa_device_fd);
 
     return -1;
-- 
2.31.1

Re: [PATCH v3 00/19] vdpa net devices Rx filter change notification with Shadow VQ

[Jason Wang]

On Sat, Jul 16, 2022 at 1:18 AM Eugenio Pérez <eperezma@redhat.com> wrote:
>
> Control virtqueue is used by networking device for accepting various
> commands from the driver. It's a must to support advanced configurations.
>
> Rx filtering event is issues by qemu when device's MAC address changed once and
> the previous one has not been queried by external agents.
>
> Shadow VirtQueue (SVQ) already makes possible tracking the state of virtqueues,
> effectively intercepting them so qemu can track what regions of memory are
> dirty because device action and needs migration. However, this does not solve
> networking device state seen by the driver because CVQ messages, like changes
> on MAC addresses from the driver.
>
> This series uses SVQ infrastructure to intercept networking control messages
> used by the device. This way, qemu is able to update VirtIONet device model and
> react to them. In particular, this series enables rx filter change
> notification.
>
> This is a prerequisite to achieve net vdpa device with CVQ live migration.
> It's a stripped down version of [1], with error paths checked and no migration
> enabled.
>
> First nine patches reorder and clean code base so its easier to apply later
> ones. No functional change should be noticed from these changes.
>
> Patches from 11 to 14 enable SVQ API to make other parts of qemu to interact
> with it. In particular, they will be used by vhost-vdpa net to handle CVQ
> messages.
>
> Patches 15 to 17 enable the update of the virtio-net device model for each
> CVQ message acknowledged by the device.
>
> Last patches enable x-svq parameter, forbidding device migration since it is
> not restored in the destination's vdpa device yet. This will be added in later
> series, using this work.
>
> Comments are welcome.
> v3:
> - Replace SVQElement with SVQDescState
>
> v2:
> - (Comments from series [1]).
> - Active poll for CVQ answer instead of relay on async used callback
> - Do not offer a new buffer to device but reuse qemu's
> - Use vhost_svq_add instead of not needed vhost_svq_inject
> - Delete used and detach callbacks, not needed anymore
> - Embed members of SVQElement in VirtQueueElement
> - Reuse the same buffers for all CVQ commands
>
> [1] https://patchwork.kernel.org/project/qemu-devel/cover/20220706184008.1649478-1-eperezma@redhat.com/
>
> Eugenio Pérez (19):
>   vhost: move descriptor translation to vhost_svq_vring_write_descs
>   virtio-net: Expose MAC_TABLE_ENTRIES
>   virtio-net: Expose ctrl virtqueue logic
>   vhost: Reorder vhost_svq_kick
>   vhost: Move vhost_svq_kick call to vhost_svq_add
>   vhost: Check for queue full at vhost_svq_add
>   vhost: Decouple vhost_svq_add from VirtQueueElement
>   vhost: Add SVQDescState
>   vhost: Track number of descs in SVQDescState
>   vhost: add vhost_svq_push_elem
>   vhost: Expose vhost_svq_add
>   vhost: add vhost_svq_poll
>   vhost: Add svq avail_handler callback
>   vdpa: Export vhost_vdpa_dma_map and unmap calls
>   vdpa: manual forward CVQ buffers
>   vdpa: Buffer CVQ support on shadow virtqueue
>   vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs
>   vdpa: Add device migration blocker
>   vdpa: Add x-svq to NetdevVhostVDPAOptions
>
>  qapi/net.json                      |   9 +-
>  hw/virtio/vhost-shadow-virtqueue.h |  52 ++++-
>  include/hw/virtio/vhost-vdpa.h     |   8 +
>  include/hw/virtio/virtio-net.h     |   7 +
>  hw/net/virtio-net.c                |  85 ++++---
>  hw/virtio/vhost-shadow-virtqueue.c | 202 +++++++++++-----
>  hw/virtio/vhost-vdpa.c             |  25 +-
>  net/vhost-vdpa.c                   | 357 +++++++++++++++++++++++++++--
>  8 files changed, 627 insertions(+), 118 deletions(-)

Looks good to me.

Michael, if you don't object, I plan to merge this series so vendors
can start to test this.

Thanks

>
> --
> 2.31.1
>
>

Re: [PATCH v3 00/19] vdpa net devices Rx filter change notification with Shadow VQ

[Michael S. Tsirkin]

On Fri, Jul 15, 2022 at 07:18:15PM +0200, Eugenio Pérez wrote:
> Control virtqueue is used by networking device for accepting various
> commands from the driver. It's a must to support advanced configurations.
> 
> Rx filtering event is issues by qemu when device's MAC address changed once and
> the previous one has not been queried by external agents.
> 
> Shadow VirtQueue (SVQ) already makes possible tracking the state of virtqueues,
> effectively intercepting them so qemu can track what regions of memory are
> dirty because device action and needs migration. However, this does not solve
> networking device state seen by the driver because CVQ messages, like changes
> on MAC addresses from the driver.
> 
> This series uses SVQ infrastructure to intercept networking control messages
> used by the device. This way, qemu is able to update VirtIONet device model and
> react to them. In particular, this series enables rx filter change
> notification.
> 
> This is a prerequisite to achieve net vdpa device with CVQ live migration.
> It's a stripped down version of [1], with error paths checked and no migration
> enabled.
> 
> First nine patches reorder and clean code base so its easier to apply later
> ones. No functional change should be noticed from these changes.
> 
> Patches from 11 to 14 enable SVQ API to make other parts of qemu to interact
> with it. In particular, they will be used by vhost-vdpa net to handle CVQ
> messages.
> 
> Patches 15 to 17 enable the update of the virtio-net device model for each
> CVQ message acknowledged by the device.
> 
> Last patches enable x-svq parameter, forbidding device migration since it is
> not restored in the destination's vdpa device yet. This will be added in later
> series, using this work.
> 
> Comments are welcome.
> v3:
> - Replace SVQElement with SVQDescState

Series:

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

> v2:
> - (Comments from series [1]).
> - Active poll for CVQ answer instead of relay on async used callback
> - Do not offer a new buffer to device but reuse qemu's
> - Use vhost_svq_add instead of not needed vhost_svq_inject
> - Delete used and detach callbacks, not needed anymore
> - Embed members of SVQElement in VirtQueueElement
> - Reuse the same buffers for all CVQ commands
> 
> [1] https://patchwork.kernel.org/project/qemu-devel/cover/20220706184008.1649478-1-eperezma@redhat.com/
> 
> Eugenio Pérez (19):
>   vhost: move descriptor translation to vhost_svq_vring_write_descs
>   virtio-net: Expose MAC_TABLE_ENTRIES
>   virtio-net: Expose ctrl virtqueue logic
>   vhost: Reorder vhost_svq_kick
>   vhost: Move vhost_svq_kick call to vhost_svq_add
>   vhost: Check for queue full at vhost_svq_add
>   vhost: Decouple vhost_svq_add from VirtQueueElement
>   vhost: Add SVQDescState
>   vhost: Track number of descs in SVQDescState
>   vhost: add vhost_svq_push_elem
>   vhost: Expose vhost_svq_add
>   vhost: add vhost_svq_poll
>   vhost: Add svq avail_handler callback
>   vdpa: Export vhost_vdpa_dma_map and unmap calls
>   vdpa: manual forward CVQ buffers
>   vdpa: Buffer CVQ support on shadow virtqueue
>   vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs
>   vdpa: Add device migration blocker
>   vdpa: Add x-svq to NetdevVhostVDPAOptions
> 
>  qapi/net.json                      |   9 +-
>  hw/virtio/vhost-shadow-virtqueue.h |  52 ++++-
>  include/hw/virtio/vhost-vdpa.h     |   8 +
>  include/hw/virtio/virtio-net.h     |   7 +
>  hw/net/virtio-net.c                |  85 ++++---
>  hw/virtio/vhost-shadow-virtqueue.c | 202 +++++++++++-----
>  hw/virtio/vhost-vdpa.c             |  25 +-
>  net/vhost-vdpa.c                   | 357 +++++++++++++++++++++++++++--
>  8 files changed, 627 insertions(+), 118 deletions(-)
> 
> -- 
> 2.31.1
> 

Re: [PATCH v3 00/19] vdpa net devices Rx filter change notification with Shadow VQ

[Michael S. Tsirkin]

On Mon, Jul 18, 2022 at 11:32:57AM +0800, Jason Wang wrote:
> On Sat, Jul 16, 2022 at 1:18 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > Control virtqueue is used by networking device for accepting various
> > commands from the driver. It's a must to support advanced configurations.
> >
> > Rx filtering event is issues by qemu when device's MAC address changed once and
> > the previous one has not been queried by external agents.
> >
> > Shadow VirtQueue (SVQ) already makes possible tracking the state of virtqueues,
> > effectively intercepting them so qemu can track what regions of memory are
> > dirty because device action and needs migration. However, this does not solve
> > networking device state seen by the driver because CVQ messages, like changes
> > on MAC addresses from the driver.
> >
> > This series uses SVQ infrastructure to intercept networking control messages
> > used by the device. This way, qemu is able to update VirtIONet device model and
> > react to them. In particular, this series enables rx filter change
> > notification.
> >
> > This is a prerequisite to achieve net vdpa device with CVQ live migration.
> > It's a stripped down version of [1], with error paths checked and no migration
> > enabled.
> >
> > First nine patches reorder and clean code base so its easier to apply later
> > ones. No functional change should be noticed from these changes.
> >
> > Patches from 11 to 14 enable SVQ API to make other parts of qemu to interact
> > with it. In particular, they will be used by vhost-vdpa net to handle CVQ
> > messages.
> >
> > Patches 15 to 17 enable the update of the virtio-net device model for each
> > CVQ message acknowledged by the device.
> >
> > Last patches enable x-svq parameter, forbidding device migration since it is
> > not restored in the destination's vdpa device yet. This will be added in later
> > series, using this work.
> >
> > Comments are welcome.
> > v3:
> > - Replace SVQElement with SVQDescState
> >
> > v2:
> > - (Comments from series [1]).
> > - Active poll for CVQ answer instead of relay on async used callback
> > - Do not offer a new buffer to device but reuse qemu's
> > - Use vhost_svq_add instead of not needed vhost_svq_inject
> > - Delete used and detach callbacks, not needed anymore
> > - Embed members of SVQElement in VirtQueueElement
> > - Reuse the same buffers for all CVQ commands
> >
> > [1] https://patchwork.kernel.org/project/qemu-devel/cover/20220706184008.1649478-1-eperezma@redhat.com/
> >
> > Eugenio Pérez (19):
> >   vhost: move descriptor translation to vhost_svq_vring_write_descs
> >   virtio-net: Expose MAC_TABLE_ENTRIES
> >   virtio-net: Expose ctrl virtqueue logic
> >   vhost: Reorder vhost_svq_kick
> >   vhost: Move vhost_svq_kick call to vhost_svq_add
> >   vhost: Check for queue full at vhost_svq_add
> >   vhost: Decouple vhost_svq_add from VirtQueueElement
> >   vhost: Add SVQDescState
> >   vhost: Track number of descs in SVQDescState
> >   vhost: add vhost_svq_push_elem
> >   vhost: Expose vhost_svq_add
> >   vhost: add vhost_svq_poll
> >   vhost: Add svq avail_handler callback
> >   vdpa: Export vhost_vdpa_dma_map and unmap calls
> >   vdpa: manual forward CVQ buffers
> >   vdpa: Buffer CVQ support on shadow virtqueue
> >   vdpa: Extract get features part from vhost_vdpa_get_max_queue_pairs
> >   vdpa: Add device migration blocker
> >   vdpa: Add x-svq to NetdevVhostVDPAOptions
> >
> >  qapi/net.json                      |   9 +-
> >  hw/virtio/vhost-shadow-virtqueue.h |  52 ++++-
> >  include/hw/virtio/vhost-vdpa.h     |   8 +
> >  include/hw/virtio/virtio-net.h     |   7 +
> >  hw/net/virtio-net.c                |  85 ++++---
> >  hw/virtio/vhost-shadow-virtqueue.c | 202 +++++++++++-----
> >  hw/virtio/vhost-vdpa.c             |  25 +-
> >  net/vhost-vdpa.c                   | 357 +++++++++++++++++++++++++++--
> >  8 files changed, 627 insertions(+), 118 deletions(-)
> 
> Looks good to me.
> 
> Michael, if you don't object, I plan to merge this series so vendors
> can start to test this.
> 
> Thanks

Sounds good.

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> >
> > --
> > 2.31.1
> >
> >