Commit 8708f682 authored Dec 12, 2017 by Cédric Le Goater Committed by Greg Kroah-Hartman Dec 29, 2017

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



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: 5af50993 ("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>

parent 4e9cca92

arch/powerpc/kvm/book3s_xive.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1558,7 +1558,7 @@ static int xive_set_source(struct kvmppc_xive *xive, long irq, u64 addr)

		/*
		* 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_xive *xive, long irq, u64 addr)
		* 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;