Top word writes just update the destination of the interrupt, but since there's no change on the masking or the triggering mode no guest interrupt injection can result of such write. Add an assert to that effect.
Requested-by: Jan Beulich <jbeul...@suse.com> Signed-off-by: Roger Pau Monné <roger....@citrix.com> --- Changes since v2: - New in this version. --- xen/arch/x86/hvm/vioapic.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/arch/x86/hvm/vioapic.c b/xen/arch/x86/hvm/vioapic.c index 804bc77279..e3ee747b7d 100644 --- a/xen/arch/x86/hvm/vioapic.c +++ b/xen/arch/x86/hvm/vioapic.c @@ -262,6 +262,8 @@ static void vioapic_write_redirent( !ent.fields.remote_irr && hvm_irq->gsi_assert_count[gsi] ) { + /* A top word write should never trigger an interrupt injection. */ + ASSERT(!top_word); pent->fields.remote_irr = 1; vioapic_deliver(vioapic, idx); } -- 2.29.2