[rhelv6-beta-list] Does kvm-virtio / xen-domu block device support "Block Discard"?

[Kirby Zhou]

Does virtio / xen-domu block device support "Block Discard"?

There are some situations requiring that feature.
1. I want to deploy guest OS on a SSD drive.
2. A size-virtualized storage pool is used by hypervisor
3. Guest-Image stored as a sparse file, and the guest FS is also "Block
Discard" sensitive. We want to make the Guest-Image size as small as
possible.

  Regards
  Kirby Zhou