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@intel.com>

diff --git a/xen/arch/x86/hvm/vmx/vtd/dmar.c b/xen/arch/x86/hvm/vmx/vtd/dmar.c
index 44ca487bdb4011914f34c6698dd887e6dec51621..7103994ff6f37133ded4d58d916eb77bfa1df2d9 100644 (file)
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.c
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.c
@@ -483,6 +483,10 @@ acpi_parse_dmar(unsigned long phys_addr, unsigned long size)
 
         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;
 }