On 24.07.26 00:30, Connor Kite wrote:
Adds features to fill a vhost_user_set_mem_table message with the
addresses of isolation memory regions corresponding to bounce buffers
and vrings.
Signed-off-by: Connor Kite <[email protected]>
---
hw/virtio/vhost-user.c | 80 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 79 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 710cf966f8..acabfb7f1c 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -625,6 +625,21 @@ static void vhost_user_fill_msg_region(struct vhost_dev
*dev,
dst->mmap_offset = mmap_offset;
}
+static void vhost_user_fill_msg_region_iso(VhostUserMemoryRegion *dst,
+ const struct vhost_user *u,
+ const struct vhost_memory_region
+ *iova_reg)
+{
+ assert(u != NULL && dst != NULL && iova_reg != NULL);
+ uint64_t offset;
+
+ offset = iova_reg->userspace_addr - u->iso_memory.base_addr;
+ dst->userspace_addr = iova_reg->userspace_addr;
+ dst->memory_size = iova_reg->memory_size;
+ dst->guest_phys_addr = iova_reg->userspace_addr;
+ dst->mmap_offset = offset;
+}
+
static int vhost_user_fill_set_mem_table_msg(struct vhost_user *u,
struct vhost_dev *dev,
VhostUserMsg *msg,
@@ -1136,7 +1151,33 @@ static void cleanup_isolation_regions(struct vhost_dev
*dev)
}
}
-__attribute__((unused))
+struct iova_tree_traversal_args {
+ VhostUserMsg *msg;
+ struct vhost_user *u;
+ int *fds;
+ size_t *fd_num;
+};
+
+static gboolean vhost_user_iova_tree_traverse_funct(gpointer key,
+ gpointer value,
+ gpointer data)
This function name doesn’t really say what the function does, and more
describes its type.
+{
+ struct iova_tree_traversal_args *args = data;
+ struct vhost_memory_region msg_region;
+ VhostUserMemoryRegion region_buffer;
+ DMAMap *map = key;
+ args->fds[*args->fd_num] = args->u->iso_memory.iso_fd;
Generally: I find it quite hard to read code where general statements
come after a list of declarations without an empty line, especially if
there is an empty line later. Visually, this last line to me looks like
another variable declaration.
+
+ msg_region.guest_phys_addr = map->iova;
+ msg_region.memory_size = map->size + 1;
+ msg_region.userspace_addr = map->iova;
+ vhost_user_fill_msg_region_iso(®ion_buffer, args->u, &msg_region);
+ args->msg->payload.memory.regions[*args->fd_num] = region_buffer;
Why does `vhost_user_fill_msg_region_iso()` exist when this is the only
caller, and we could just fill `regions[i]` here directly?
+ (*args->fd_num)++;
As noted by Akihiko, there needs to be some bounds checking. At least
against `VHOST_MEMORY_BASELINE_NREGIONS`, but even better against the
array size of `args->msg->payload.memory.regions` and the caller should
pass the size of `fds[]` via `args`.
(And I’m also with Stefan, something with `index` would be better. Maybe
`region_idx`.)
+
+ return false;
+}
+
static int init_isolation_regions(struct vhost_dev *dev,
VhostUserMsg *msg,
int *fds, size_t *fd_num)
@@ -1234,6 +1275,24 @@ static int init_isolation_regions(struct vhost_dev *dev,
map->translated_addr);
}
+ struct iova_tree_traversal_args args = {
+ .fd_num = fd_num,
+ .fds = fds,
+ .msg = msg,
+ .u = u
+ };
Personal preference: I would like `*fd_num = 0` somewhere here, or
`assert(*fd_num == 0)` before the iteration. Yes, the caller initializes
it to zero, but it is just not obvious here, and it seems necessary for
correct semantics.
(And the open question whether `fd_num` should be renamed here, too, or
can keep that name. Not sure.)
+
+ vhost_iova_tree_foreach(u->iso_iova_tree,
+ vhost_user_iova_tree_traverse_funct, &args);
+
+ msg->payload.memory.nregions = *fd_num;
+
+ assert(*fd_num != 0);
Am I wrong or should `*fd_num == nregions`? Is it possible that
`*fd_num` is less because regions end up joined? Can you add a comment
on when they would differ?
Hanna
+
+ msg->hdr.size = sizeof(msg->payload.memory.nregions);
+ msg->hdr.size += sizeof(msg->payload.memory.padding);
+ msg->hdr.size += *fd_num * sizeof(VhostUserMemoryRegion);
+
return 0;
}
[...]
