chardev: block during sync read

A sync read should block until all requested data is
available (instead of retrying in qemu_chr_fe_read_all). Change the
channel to blocking during sync_read.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170706170353.32601-1-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
1 file changed