x86/vioapic: fix usage of index in place of GSI in vioapic_write_redirent

The usage of idx instead of the GSI in vioapic_write_redirent when
accessing gsi_assert_count can cause a PVH dom0 with multiple
vIO-APICs to lose interrupts in case a pin of a IO-APIC different than
the first one is unmasked with pending interrupts.

Switch to use gsi instead to fix the issue.

Fixes: 9f44b08f7d0e4 ('x86/vioapic: introduce support for multiple vIO APICS')
Reported-by: Manuel Bouyer <bouyer@antioche.eu.org>
Signed-off-by: Roger Pau Monné <roge.rpau@citrix.com>
Tested-by: Manuel Bouyer <bouyer@antioche.eu.org>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/hvm/vioapic.c b/xen/arch/x86/hvm/vioapic.c
index 67d4a6237f6198cf76d2a6ab45730fd32d49aecd..e64abee7a9a935bbd28bf080bf334dbdb0b3c132 100644 (file)
--- a/xen/arch/x86/hvm/vioapic.c
+++ b/xen/arch/x86/hvm/vioapic.c
@@ -260,7 +260,7 @@ static void vioapic_write_redirent(
         pent->fields.remote_irr = 0;
     else if ( !ent.fields.mask &&
               !ent.fields.remote_irr &&
-              hvm_irq->gsi_assert_count[idx] )
+              hvm_irq->gsi_assert_count[gsi] )
     {
         pent->fields.remote_irr = 1;
         vioapic_deliver(vioapic, idx);