[RFC 5/8] vdpa: Add vdpa memory listener

["Eugenio Pérez" <eperezma@redhat.com>]

This enable net/vdpa to restart the full device when a migration is
started or stopped.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index a035c89c34..4c6947feb8 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -21,6 +21,7 @@
 #include "qemu/memalign.h"
 #include "qemu/option.h"
 #include "qapi/error.h"
+#include "exec/address-spaces.h"
 #include <linux/vhost.h>
 #include <sys/ioctl.h>
 #include <err.h>
@@ -32,6 +33,8 @@
 typedef struct VhostVDPAState {
     NetClientState nc;
     struct vhost_vdpa vhost_vdpa;
+    MemoryListener memory_listener;
+
     VHostNetState *vhost_net;
 
     /* Control commands shadow buffers */
@@ -110,6 +113,16 @@ static const uint64_t vdpa_svq_device_features =
 #define VHOST_VDPA_NET_CVQ_PASSTHROUGH 0
 #define VHOST_VDPA_NET_CVQ_ASID 1
 
+/*
+ * Vdpa memory listener must run before vhost one, so vhost_vdpa does not get
+ * _F_LOG_ALL without SVQ.
+ */
+#define VHOST_VDPA_NET_MEMORY_LISTENER_PRIORITY \
+                                       (VHOST_DEV_MEMORY_LISTENER_PRIORITY - 1)
+/* Check for underflow */
+QEMU_BUILD_BUG_ON(VHOST_DEV_MEMORY_LISTENER_PRIORITY <
+                  VHOST_VDPA_NET_MEMORY_LISTENER_PRIORITY);
+
 VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc)
 {
     VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
@@ -172,6 +185,9 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
 
     qemu_vfree(s->cvq_cmd_out_buffer);
     qemu_vfree(s->cvq_cmd_in_buffer);
+    if (dev->vq_index == 0) {
+        memory_listener_unregister(&s->memory_listener);
+    }
     if (dev->vq_index + dev->nvqs == dev->vq_index_end) {
         g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete);
     }
@@ -224,6 +240,69 @@ static ssize_t vhost_vdpa_receive(NetClientState *nc, const uint8_t *buf,
     return 0;
 }
 
+static void vhost_vdpa_net_log_global_enable(MemoryListener *listener,
+                                             bool enable)
+{
+    VhostVDPAState *s = container_of(listener, VhostVDPAState,
+                                     memory_listener);
+    struct vhost_vdpa *v = &s->vhost_vdpa;
+    VirtIONet *n;
+    VirtIODevice *vdev;
+    int data_queue_pairs, cvq, r;
+    NetClientState *peer;
+
+    if (s->always_svq || s->log_enabled == enable) {
+        return;
+    }
+
+    s->log_enabled = enable;
+    vdev = v->dev->vdev;
+    n = VIRTIO_NET(vdev);
+    if (!n->vhost_started) {
+        return;
+    }
+
+    if (enable) {
+        ioctl(v->device_fd, VHOST_VDPA_SUSPEND);
+    }
+    data_queue_pairs = n->multiqueue ? n->max_queue_pairs : 1;
+    cvq = virtio_vdev_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ) ?
+                                  n->max_ncs - n->max_queue_pairs : 0;
+    vhost_net_stop(vdev, n->nic->ncs, data_queue_pairs, cvq);
+
+    peer = s->nc.peer;
+    for (int i = 0; i < data_queue_pairs + cvq; i++) {
+        VhostVDPAState *vdpa_state;
+        NetClientState *nc;
+
+        if (i < data_queue_pairs) {
+            nc = qemu_get_peer(peer, i);
+        } else {
+            nc = qemu_get_peer(peer, n->max_queue_pairs);
+        }
+
+        vdpa_state = DO_UPCAST(VhostVDPAState, nc, nc);
+        vdpa_state->vhost_vdpa.listener_shadow_vq = enable;
+        vdpa_state->vhost_vdpa.shadow_vqs_enabled = enable;
+        vdpa_state->log_enabled = enable;
+    }
+
+    r = vhost_net_start(vdev, n->nic->ncs, data_queue_pairs, cvq);
+    if (unlikely(r < 0)) {
+        error_report("unable to start vhost net: %s(%d)", g_strerror(-r), -r);
+    }
+}
+
+static void vhost_vdpa_net_log_global_start(MemoryListener *listener)
+{
+    vhost_vdpa_net_log_global_enable(listener, true);
+}
+
+static void vhost_vdpa_net_log_global_stop(MemoryListener *listener)
+{
+    vhost_vdpa_net_log_global_enable(listener, false);
+}
+
 static NetClientInfo net_vhost_vdpa_info = {
         .type = NET_CLIENT_DRIVER_VHOST_VDPA,
         .size = sizeof(VhostVDPAState),
@@ -413,6 +492,7 @@ static void vhost_vdpa_net_cvq_stop(NetClientState *nc)
 
     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
 
+    memory_listener_unregister(&s->memory_listener);
     if (s->vhost_vdpa.shadow_vqs_enabled) {
         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_in_buffer);
@@ -671,6 +751,13 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
     s->vhost_vdpa.shadow_vqs_enabled = svq;
     s->vhost_vdpa.listener_shadow_vq = svq;
     s->vhost_vdpa.iova_tree = iova_tree;
+    if (queue_pair_index == 0) {
+        s->memory_listener = (MemoryListener) {
+            .log_global_start = vhost_vdpa_net_log_global_start,
+            .log_global_stop = vhost_vdpa_net_log_global_stop,
+        };
+        memory_listener_register(&s->memory_listener, &address_space_memory);
+    }
     if (!is_datapath) {
         s->cvq_cmd_out_buffer = qemu_memalign(qemu_real_host_page_size(),
                                             vhost_vdpa_net_cvq_cmd_page_len());
-- 
2.31.1