Re: [PATCH] powerpc/pseries: Add POWER8NVL support to ibm,client-architecture-support call

On 08.06.2016 03:14, Balbir Singh wrote:

On 31/05/16 20:32, Michael Ellerman wrote:

quoted

On Tue, 2016-05-31 at 12:19 +0200, Thomas Huth wrote:

quoted

On 31.05.2016 12:04, Michael Ellerman wrote:

quoted

On Tue, 2016-05-31 at 07:51 +0200, Thomas Huth wrote:

quoted

If we do not provide the PVR for POWER8NVL, a guest on this
system currently ends up in PowerISA 2.06 compatibility mode on
KVM, since QEMU does not provide a generic PowerISA 2.07 mode yet.
So some new instructions from POWER8 (like "mtvsrd") get disabled
for the guest, resulting in crashes when using code compiled
explicitly for POWER8 (e.g. with the "-mcpu=power8" option of GCC).

Signed-off-by: Thomas Huth <redacted>

So this should say:

  Fixes: ddee09c099c3 ("powerpc: Add PVR for POWER8NVL processor")

And therefore:

  Cc: stable@vger.kernel.org # v4.0+

Am I right?

Right. (At least for virtualized systems ... for bare-metal systems,
that original patch was enough). So shall I resubmit my patch with these
two lines, or could you add them when you pick this patch up?

Thanks, I'll add them here.

Don't we need to update IBM_ARCH_VEC_NRCORES_OFFSET as well?

D'oh! You're right, that needs to be changed, too! I'll send a fixup
patch once I've tested it...

By the way, there seems to be already a check for
ibm_architecture_vec[IBM_ARCH_VEC_NRCORES_OFFSET] != NR_CPUS in
prom_send_capabilities(), but it only prints out a warning which easily
gets lost in the kernel log ... I wonder whether we should rather stop
the boot there instead to catch this problem more easily?

 Thomas