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

[Paul Mackerras]

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.

Cheers,
Paul.