+ * Returns: 0 on success, negative errno on failure
+ */
+static int
+vhost_user_backend_handle_shmem_map(struct vhost_dev *dev,
+ QIOChannel *ioc,
+ VhostUserHeader *hdr,
+ VhostUserPayload *payload,
+ int fd)
+{
+ VirtioSharedMemory *shmem;
+ VhostUserMMap *vu_mmap = &payload->mmap;
+ VirtioSharedMemoryMapping *existing;
+ Error *local_err = NULL;
+ int ret = 0;
+
+ if (fd < 0) {
+ error_report("Bad fd for map");
+ ret = -EBADF;
+ goto send_reply;
+ }
+
+ if (QSIMPLEQ_EMPTY(&dev->vdev->shmem_list)) {
+ error_report("Device has no VIRTIO Shared Memory Regions. "
+ "Requested ID: %d", vu_mmap->shmid);
+ ret = -EFAULT;
+ goto send_reply;
+ }
+
+ shmem = virtio_find_shmem_region(dev->vdev, vu_mmap->shmid);
+ if (!shmem) {
+ error_report("VIRTIO Shared Memory Region at "
+ "ID %d not found or uninitialized", vu_mmap->shmid);
+ ret = -EFAULT;
+ goto send_reply;
+ }
+
+ if ((vu_mmap->shm_offset + vu_mmap->len) < vu_mmap->len ||
+ (vu_mmap->shm_offset + vu_mmap->len) > shmem->mr.size) {
+ error_report("Bad offset/len for mmap %" PRIx64 "+%" PRIx64,
+ vu_mmap->shm_offset, vu_mmap->len);
+ ret = -EFAULT;
+ goto send_reply;
+ }
+
+ QTAILQ_FOREACH(existing, &shmem->mmaps, link) {
+ if (ranges_overlap(existing->offset, existing->len,
+ vu_mmap->shm_offset, vu_mmap->len)) {
+ error_report("VIRTIO Shared Memory mapping overlap");
+ ret = -EFAULT;
+ goto send_reply;
+ }
+ }
+
+ memory_region_transaction_begin();
My only comment would be whether the
memory_region_transaction_begin()/memory_region_transaction_commit()
should be hidden behind some
virtio_add_shmem_map_start()/virtio_add_shmem_map_end() helpers.
Talking about memory regions in this function sounds odd given that it's
more an implementation detail hidden by other helpers.
Then, we can also document why these functions exists, and what the
contract is for calling them.
--
Cheers
David / dhildenb
