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 <b...@kernel.crashing.org> > Signed-off-by: Cédric Le Goater <c...@kaod.org> > --- > > Tested with a guest running iozone. > > arch/powerpc/kvm/book3s_xive.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c > index bf457843e032..b5e6d227a034 100644 > --- 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_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; >
Reviewed-by: Laurent Vivier <lviv...@redhat.com> Tested-by: Laurent Vivier <lviv...@redhat.com>
