[PATCH v2 1/2] qemu_capabilities: Introduce QEMU_CAPS_X_USE_CANONICAL_PATH_FOR_RAMBLOCK_ID

[Peter Krempa]

On Thu, Jan 14, 2021 at 13:37:23 +0100, Michal Privoznik wrote:
> This capability tracks whether memory-backend-file has
> "x-use-canonical-path-for-ramblock-id" attribute. Introduced into
> QEMU by commit fa0cb34d2210cc749b9a70db99bb41c56ad20831. While
> "x-" prefix is considered experimental or internal to QEMU, the
> next commit justifies its use.

Since the detection of this feature is not limited to existing qemus, my
requirement that qemu must add acknowledgement that
"x-use-canonical-path-for-ramblock-id" will be treated as a stable
feature from now on and the qemu commit adding that must be mentioned in
this commit.

The only other way is to limit the feature detection to any released
qemu (thus qemu-5.2 and previous), since we still will not get a
guarantee that they will not change the flag in the future.