On Thu, Jul 23, 2026 at 03:30:11PM -0700, 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 {
QEMU coding style:
typedef struct {
...
} IOVATreeTraversalArgs;
> + VhostUserMsg *msg;
> + struct vhost_user *u;
> + int *fds;
> + size_t *fd_num;
This field is also used to index into msg->payload.memory.regions[], so
"fd_num" is a misnomer. I suggest something like "region_idx" or just
"idx".
> +};
> +
> +static gboolean vhost_user_iova_tree_traverse_funct(gpointer key,
> + gpointer value,
> + gpointer data)
> +{
> + 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;
> +
> + 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;
I'm confused by this code. VhostUserMemoryRegion region_buffer is the
vhost-user protocol struct that is being filled in, but there is also a
struct vhost_memory_region msg_region from the Linux kernel headers?
msg_region and vhost_user_fill_msg_region_iso() make it harder to see
what is going on. Can you open code the region_buffer struct field
assignments instead?
> + (*args->fd_num)++;
> +
> + 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
> + };
> +
> + 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);
> +
> + 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;
> }
>
> @@ -1241,6 +1300,7 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> struct vhost_memory *mem)
> {
> struct vhost_user *u = dev->opaque;
> + bool memory_isolation = u->user->memory_isolation;
> int fds[VHOST_MEMORY_BASELINE_NREGIONS];
> size_t fd_num = 0;
> bool do_postcopy = u->postcopy_listen && u->postcopy_fd.handler;
> @@ -1268,6 +1328,24 @@ static int vhost_user_set_mem_table(struct vhost_dev
> *dev,
> msg.hdr.flags |= VHOST_USER_NEED_REPLY_MASK;
> }
>
> + if (memory_isolation) {
> + ret = init_isolation_regions(dev, &msg, fds, &fd_num);
> + if (ret < 0) {
> + return ret;
> + }
> +
> + ret = vhost_user_write(dev, &msg, fds, fd_num);
> + if (ret < 0) {
> + return ret;
> + }
> +
> + if (reply_supported) {
> + return process_message_reply(dev, &msg);
> + }
> +
> + return 0;
> + }
> +
> if (config_mem_slots) {
> ret = vhost_user_add_remove_regions(dev, &msg, reply_supported,
> false);
> if (ret < 0) {
>
> --
> 2.43.0
>
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