src is stored in shared memory and src->nr_segments is dereferenced
twice at the end of the function. If a compiler decides to compile this
into two separate memory accesses then the size limitation could be
bypassed.
Fix it by removing the double access to src->nr_segments.
This is part of XSA-155.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Implement discard support for xen_disk. It makes use of the existing
discard code in qemu.
The discard support is enabled unconditionally. The tool stack may
provide a property "discard-enable" in the backend node to optionally
disable discard support. This is helpful in case the backing file was
intentionally created non-sparse to avoid fragmentation.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
