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

[Laurent Vivier]

On 22/12/2017 08:54, Paul Mackerras wrote:
> On Fri, Dec 22, 2017 at 03:34:20PM +1100, Michael Ellerman wrote:
>> 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+
> 
> Thanks for doing that.
> 
> If you felt like merging Alexey's patch "KVM: PPC: Book3S PR: Fix WIMG
> handling under pHyp" with my acked-by, that would be fine too.  The
> commit message needs a little work - the reason for using HPTE_R_M is
> not just because it seems to work, but because current POWER
> processors require M set on mappings for normal pages, and pHyp
> enforces that.

We also need:

KVM: PPC: Book3S HV: Fix pending_pri value in kvmppc_xive_get_icp()

Thanks,
Laurent