VT-d: correct off-by-1 in number-of-IOMMUs check

Otherwise, if we really run on a system with this many IOMMUs,
entering/leaving S3 would overrun iommu_state[].

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
master commit: b9b3082002cac68726fb303e0abd2ff0113d4657
master date: 2021-03-23 17:01:30 +0100

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 58128be8b5d64272485168a0156a23ccb1cc9ead..ca09cd515c2d8981e07c93829d1016b98e1605b8 100644 (file)
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1163,10 +1163,10 @@ int __init iommu_alloc(struct acpi_drhd_unit *drhd)
     unsigned long sagaw, nr_dom;
     int agaw;
 
-    if ( nr_iommus > MAX_IOMMUS )
+    if ( nr_iommus >= MAX_IOMMUS )
     {
         dprintk(XENLOG_ERR VTDPREFIX,
-                 "IOMMU: nr_iommus %d > MAX_IOMMUS\n", nr_iommus);
+                "IOMMU: nr_iommus %d > MAX_IOMMUS\n", nr_iommus + 1);
         return -ENOMEM;
     }