On 13/12/2017 19:08, Dr. David Alan Gilbert (git) wrote:
> + if (dev->tmp_mem->nregions) {
> + /* Since we already have at least one region, lets see if
> + * this extends it; since we're scanning in order, we only
> + * have to look at the last one, and the FlatView that calls
> + * us shouldn't have overlaps.
> + */
> + struct vhost_memory_region *prev_vmr = dev->tmp_mem->regions +
> + (dev->tmp_mem->nregions - 1);
> + uint64_t prev_gpa_start = prev_vmr->guest_phys_addr;
> + uint64_t prev_gpa_end = range_get_last(prev_gpa_start,
> + prev_vmr->memory_size);
> + uint64_t prev_host_start = prev_vmr->userspace_addr;
> + uint64_t prev_host_end = range_get_last(prev_host_start,
> + prev_vmr->memory_size);
> +
> + if (prev_gpa_end + 1 == mrs_gpa &&
> + prev_host_end + 1 == mrs_host &&
> + (!dev->vhost_ops->vhost_backend_can_merge ||
> + dev->vhost_ops->vhost_backend_can_merge(dev,
> + mrs_host, mrs_size,
> + prev_host_start, prev_vmr->memory_size))) {
> + /* The two regions abut */
> + need_add = false;
> + mrs_size = mrs_size + prev_vmr->memory_size;
> + prev_vmr->memory_size = mrs_size;
> + trace_vhost_region_add_tmp_abut(section->mr->name, mrs_size);
> + }
> + }
Interesting, in which cases does this actually trigger?
Paolo
