[Xen-changelog] [xen-unstable] VT-d: don't reject valid DMAR/ATSR tables on systems with multiple PCI segments

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxxxx>
# Date 1313226769 -3600
# Node ID 8f647d409196f1d018f6284af03d1625cf8f93af
# Parent  537ed3b74b3f13267cfb3eb0e1483f432f3685cd
VT-d: don't reject valid DMAR/ATSR tables on systems with multiple PCI segments

On multi-PCI-segment systems, each segment has to be expected to have
an include-all DRHD and an all-ports ATSR, so the firmware consistency
check incorrectly rejects valid configurations there (which is
particularly problematic when the firmware also pre-enabled x2apic
mode, as the system will panic in that case due to being unable to
enable interrupt remapping). Thus constrain the check to just segment
0 for now; once full multi-segment support is there (which I'm working
on), it can be revisited whether we'd want to track this per segment,
or whether we trust the firmware of such large systems.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
---


diff -r 537ed3b74b3f -r 8f647d409196 xen/drivers/passthrough/vtd/dmar.c
--- a/xen/drivers/passthrough/vtd/dmar.c        Fri Aug 12 11:29:24 2011 +0100
+++ b/xen/drivers/passthrough/vtd/dmar.c        Sat Aug 13 10:12:49 2011 +0100
@@ -418,13 +418,14 @@
         if ( iommu_verbose )
             dprintk(VTDPREFIX, "  flags: INCLUDE_ALL\n");
         /* Only allow one INCLUDE_ALL */
-        if ( include_all )
+        if ( drhd->segment == 0 && include_all )
         {
             dprintk(XENLOG_WARNING VTDPREFIX,
                     "Only one INCLUDE_ALL device scope is allowed\n");
             ret = -EINVAL;
         }
-        include_all = 1;
+        if ( drhd->segment == 0 )
+            include_all = 1;
     }
 
     if ( ret )
@@ -624,13 +625,14 @@
         if ( iommu_verbose )
             dprintk(VTDPREFIX, "  flags: ALL_PORTS\n");
         /* Only allow one ALL_PORTS */
-        if ( all_ports )
+        if ( atsr->segment == 0 && all_ports )
         {
             dprintk(XENLOG_WARNING VTDPREFIX,
                     "Only one ALL_PORTS device scope is allowed\n");
             ret = -EINVAL;
         }
-        all_ports = 1;
+        if ( atsr->segment == 0 )
+            all_ports = 1;
     }
 
     if ( ret )

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