Patch "KVM: PPC: Book3S: fix XIVE migration of pending interrupts" has been added to the 4.14-stable tree

Patch "KVM: PPC: Book3S: fix XIVE migration of pending interrupts" has been added to the 4.14-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    KVM: PPC: Book3S: fix XIVE migration of pending interrupts

to the 4.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-ppc-book3s-fix-xive-migration-of-pending-interrupts.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From dc1c4165d189350cb51bdd3057deb6ecd164beda Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>
Date: Tue, 12 Dec 2017 12:02:04 +0000
Subject: KVM: PPC: Book3S: fix XIVE migration of pending interrupts
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Content-Type: text/plain; charset=UTF-8
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From: Cédric Le Goater <clg@kaod.org>

commit dc1c4165d189350cb51bdd3057deb6ecd164beda upstream.

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.

Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Laurent Vivier <lvivier@redhat.com>
Tested-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/kvm/book3s_xive.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -1558,7 +1558,7 @@ static int xive_set_source(struct kvmppc
 
 	/*
 	 * Restore P and Q. If the interrupt was pending, we
-	 * force both P and Q, which will trigger a resend.
+	 * force Q and !P, which will trigger a resend.
 	 *
 	 * That means that a guest that had both an interrupt
 	 * pending (queued) and Q set will restore with only
@@ -1566,7 +1566,7 @@ static int xive_set_source(struct kvmppc
 	 * is perfectly fine as coalescing interrupts that haven't
 	 * been presented yet is always allowed.
 	 */
-	if (val & KVM_XICS_PRESENTED || val & KVM_XICS_PENDING)
+	if (val & KVM_XICS_PRESENTED && !(val & KVM_XICS_PENDING))
 		state->old_p = true;
 	if (val & KVM_XICS_QUEUED || val & KVM_XICS_PENDING)
 		state->old_q = true;


Patches currently in stable-queue which might be from clg@kaod.org are

queue-4.14/kvm-ppc-book3s-fix-xive-migration-of-pending-interrupts.patch