commit 51d59a64eed6c2cd2d2f991f44ffbe21eb33c733
author Si-Wei Liu <si-wei.liu@oracle.com> Thu Mar 14 13:27:34 2024 -0700
committer Michael S. Tsirkin <mst@redhat.com> Mon Jul 01 14:56:23 2024 -0400
tree 9235e0fc7691cd8bb84acc614dd3fdfd1537e5d3
parent 1152a0414944f03231f3177207d379d58125890e

vhost: dirty log should be per backend type

There could be a mix of both vhost-user and vhost-kernel clients
in the same QEMU process, where separate vhost loggers for the
specific vhost type have to be used. Make the vhost logger per
backend type, and have them properly reference counted.

Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
Message-Id: <1710448055-11709-1-git-send-email-si-wei.liu@oracle.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/virtio/vhost.c

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 4acd77e..a1e8b79 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -43,8 +43,8 @@
     do { } while (0)
 #endif
 
-static struct vhost_log *vhost_log;
-static struct vhost_log *vhost_log_shm;
+static struct vhost_log *vhost_log[VHOST_BACKEND_TYPE_MAX];
+static struct vhost_log *vhost_log_shm[VHOST_BACKEND_TYPE_MAX];
 
 /* Memslots used by backends that support private memslots (without an fd). */
 static unsigned int used_memslots;
@@ -287,6 +287,10 @@
         r = -1;
     }
 
+    if (r == 0) {
+        assert(dev->vhost_ops->backend_type == backend_type);
+    }
+
     return r;
 }
 
@@ -319,16 +323,22 @@
     return log;
 }
 
-static struct vhost_log *vhost_log_get(uint64_t size, bool share)
+static struct vhost_log *vhost_log_get(VhostBackendType backend_type,
+                                       uint64_t size, bool share)
 {
-    struct vhost_log *log = share ? vhost_log_shm : vhost_log;
+    struct vhost_log *log;
+
+    assert(backend_type > VHOST_BACKEND_TYPE_NONE);
+    assert(backend_type < VHOST_BACKEND_TYPE_MAX);
+
+    log = share ? vhost_log_shm[backend_type] : vhost_log[backend_type];
 
     if (!log || log->size != size) {
         log = vhost_log_alloc(size, share);
         if (share) {
-            vhost_log_shm = log;
+            vhost_log_shm[backend_type] = log;
         } else {
-            vhost_log = log;
+            vhost_log[backend_type] = log;
         }
     } else {
         ++log->refcnt;
@@ -340,11 +350,20 @@
 static void vhost_log_put(struct vhost_dev *dev, bool sync)
 {
     struct vhost_log *log = dev->log;
+    VhostBackendType backend_type;
 
     if (!log) {
         return;
     }
 
+    assert(dev->vhost_ops);
+    backend_type = dev->vhost_ops->backend_type;
+
+    if (backend_type == VHOST_BACKEND_TYPE_NONE ||
+        backend_type >= VHOST_BACKEND_TYPE_MAX) {
+        return;
+    }
+
     --log->refcnt;
     if (log->refcnt == 0) {
         /* Sync only the range covered by the old log */
@@ -352,13 +371,13 @@
             vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1);
         }
 
-        if (vhost_log == log) {
+        if (vhost_log[backend_type] == log) {
             g_free(log->log);
-            vhost_log = NULL;
-        } else if (vhost_log_shm == log) {
+            vhost_log[backend_type] = NULL;
+        } else if (vhost_log_shm[backend_type] == log) {
             qemu_memfd_free(log->log, log->size * sizeof(*(log->log)),
                             log->fd);
-            vhost_log_shm = NULL;
+            vhost_log_shm[backend_type] = NULL;
         }
 
         g_free(log);
@@ -376,7 +395,8 @@
 
 static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size)
 {
-    struct vhost_log *log = vhost_log_get(size, vhost_dev_log_is_shared(dev));
+    struct vhost_log *log = vhost_log_get(dev->vhost_ops->backend_type,
+                                          size, vhost_dev_log_is_shared(dev));
     uint64_t log_base = (uintptr_t)log->log;
     int r;
 
@@ -2044,7 +2064,8 @@
         uint64_t log_base;
 
         hdev->log_size = vhost_get_log_size(hdev);
-        hdev->log = vhost_log_get(hdev->log_size,
+        hdev->log = vhost_log_get(hdev->vhost_ops->backend_type,
+                                  hdev->log_size,
                                   vhost_dev_log_is_shared(hdev));
         log_base = (uintptr_t)hdev->log->log;
         r = hdev->vhost_ops->vhost_set_log_base(hdev,