On Mon, 16 Feb 2026 at 03:45, Richard Henderson
<[email protected]> wrote:
>
> RFC mostly because the kernel support is not yet upsteam.
> This is based on
>
> https://lore.kernel.org/linux-arm-kernel/[email protected]/
>
> Properly testing this will take more time.  I'm not 100%
> sure how to confirm that the SME registers have the correct
> value across migration.
>
> I'm thinking of a test case in which the ZArray is loaded,
> the test program pauses, migration or vm save/load initiated,
> and the ZArray contents are verified after continuing.
> But anything that takes timing into account like that
> seems way sketchy, so I dunno.

You could avoid the timing dependency by having a test
harness that combined QMP and the gdbstub, so that your
test program does "set up registers; bkpt; ..." and then
you wait for the gdbstub to inform you that the VM has
stopped at the breakpoint, before doing a vmsave over QMP.
Having to manage two communications channels to the QEMU
process might be a bit tedious, though.

(We could avoid the two-channels thing by adding a
gdbstub QEMU-specific maintenance packet for "execute
this monitor command" but unless we think that would be
actively helpful for users it seems a bit hacky.)

-- PMM

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