Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210526a' into staging

Virtiofs, migration and hmp pull 2021-05-26

Fixes for a loadvm regression from Kevin,
some virtiofsd cleanups from Vivek and Mahmoud, and
some RDMA migration fixups from Li.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Wed 26 May 2021 18:43:30 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20210526a:
  migration/rdma: source: poll cm_event from return path
  migration/rdma: destination: create the return patch after the first accept
  migration/rdma: Fix rdma_addrinfo res leaks
  migration/rdma: cleanup rdma in rdma_start_incoming_migration error path
  migration/rdma: Fix cm_event used before being initialized
  tools/virtiofsd/fuse_opt.c: Replaced a malloc with GLib's g_try_malloc
  tools/virtiofsd/buffer.c: replaced a calloc call with GLib's g_try_new0
  virtiofsd: Set req->reply_sent right after sending reply
  virtiofsd: Check EOF before short read
  virtiofsd: Simplify skip byte logic
  virtiofsd: get rid of in_sg_left variable
  virtiofsd: Use iov_discard_front() to skip bytes
  virtiofsd: Get rid of unreachable code in read
  virtiofsd: Check for EINTR in preadv() and retry
  hmp: Fix loadvm to resume the VM on success instead of failure

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>