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

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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: 5af5099385 ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org # v4.12+
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>
This commit is contained in:
Cédric Le Goater 2017-12-12 12:02:04 +00:00 committed by Michael Ellerman
parent 182dc9c7f2
commit dc1c4165d1
1 changed files with 2 additions and 2 deletions
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4
arch/powerpc/kvm/book3s_xive.c
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@ -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;