[Xen-changelog] [xen-unstable] This patch ensures xen vmm has exclusive access of vt-d hw by zapping

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir@xxxxxxxxxxxxx>
# Date 1191487231 -3600
# Node ID 4881f984e06ecb481ab49e4c37046d387053535b
# Parent  5a9c89cd5c7e1b5dceca0d777eff6bd67d2826db
This patch ensures xen vmm has exclusive access of vt-d hw by zapping
vt-d "DMAR" ACPI table signature after xen has finished using it.

Signed-off-by: Allen Kay <allen.m.kay@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vtd/dmar.c |    4 ++++
 1 files changed, 4 insertions(+)

diff -r 5a9c89cd5c7e -r 4881f984e06e xen/arch/x86/hvm/vmx/vtd/dmar.c
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.c   Thu Oct 04 09:39:40 2007 +0100
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.c   Thu Oct 04 09:40:31 2007 +0100
@@ -483,6 +483,10 @@ acpi_parse_dmar(unsigned long phys_addr,
 
         entry_header = ((void *)entry_header + entry_header->length);
     }
+
+    /* Zap APCI DMAR signature to prevent dom0 using vt-d HW. */
+    dmar->header.signature[0] = '\0';
+
     return ret;
 }
 

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