From: Vulnerability Report <vr@darknavy.com>

Reject pirq == s->nr_pirqs in xen_physdev_map_pirq().

Fixes: aa98ee38a5 ("hw/xen: Implement emulated PIRQ hypercall support")
Fixes: CVE-2026-0665
Reported-by: DARKNAVY (@DarkNavyOrg) <vr@darknavy.com>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Vulnerability Report <vr@darknavy.com>
Link: https://lore.kernel.org/r/13FE03BE60EA78D6+20260109023548.4047-1-vr@darknavy.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit c7504ba2a560fd884557f6e5142f03b491aad0c7)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/hw/i386/kvm/xen_evtchn.c b/hw/i386/kvm/xen_evtchn.c
index dd566c4967..173e0818c7 100644
--- a/hw/i386/kvm/xen_evtchn.c
+++ b/hw/i386/kvm/xen_evtchn.c
@@ -1877,7 +1877,7 @@ int xen_physdev_map_pirq(struct physdev_map_pirq *map)
             return pirq;
         }
         map->pirq = pirq;
-    } else if (pirq > s->nr_pirqs) {
+    } else if (pirq >= s->nr_pirqs) {
         return -EINVAL;
     } else {
         /*
-- 
2.47.3