From: Jan Beulich <jbeulich@suse.com>
Date: Tue, 23 Mar 2021 16:01:30 +0000 (+0100)
Subject: VT-d: correct off-by-1 in number-of-IOMMUs check
X-Git-Tag: archive/raspbian/4.16.0+51-g0941d6cb-1+rpi1~2^2~42^2~806
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b9b3082002cac68726fb303e0abd2ff0113d4657;p=xen.git

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>
Release-Acked-by: Ian Jackson <iwj@xenproject.org>
---

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 9b58d566c8..44e407d19f 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1168,10 +1168,10 @@ 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;
     }