[PATCH] KVM: PPC: Book3S: fix XIVE migration of pending interrupts

[Michael Ellerman]

Laurent Vivier <lvivier at redhat.com> writes:

> On 12/12/2017 13:02, Cédric Le Goater wrote:
>> When restoring a pending interrupt, we are setting the Q bit to force
>> a retrigger in xive_finish_unmask(). But we also need to force an EOI
>> in this case to reach the same initial state : P=1, Q=0.
>> 
>> This can be done by not setting 'old_p' for pending interrupts which
>> will inform xive_finish_unmask() that an EOI needs to be sent.
>> 
>> Suggested-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
>> Signed-off-by: Cédric Le Goater <clg at kaod.org>
>> ---
>> 
>>  Tested with a guest running iozone.
>> 
>>  arch/powerpc/kvm/book3s_xive.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> We really need this patch to fix VM migration on POWER9.
> When will it be merged?

Paul is away, so I'll merge it via the powerpc tree.

I'll mark it:

  Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
  Cc: stable at vger.kernel.org # v4.12+

cheers