From: Keir Fraser <keir@xensource.com>
Date: Sun, 23 Sep 2007 11:55:50 +0000 (+0100)
Subject: vt-d: disable for old chipset steppings with incompatible page table format.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~14937^2~39
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=2c1be8f16a88604b9199c7dcb04f1d07b78242a2;p=xen.git

vt-d: disable for old chipset steppings with incompatible page table format.
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 784af11818..44ca487bdb 100644
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.c
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.c
@@ -489,6 +489,13 @@ acpi_parse_dmar(unsigned long phys_addr, unsigned long size)
 int acpi_dmar_init(void)
 {
     extern int ioapic_ack_new;
+    int rc;
+
+    if (!vtd_enabled)
+        return -ENODEV;
+
+    if ((rc = vtd_hw_check()) != 0)
+        return rc;
 
     acpi_table_parse(ACPI_DMAR, acpi_parse_dmar);
 
@@ -499,8 +506,7 @@ int acpi_dmar_init(void)
     }
 
     /* Use fake-vector style of IOAPIC acknowledgement. */
-    if (vtd_enabled)
-        ioapic_ack_new = 0;
+    ioapic_ack_new = 0;
 
     return 0;
 }
diff --git a/xen/arch/x86/hvm/vmx/vtd/dmar.h b/xen/arch/x86/hvm/vmx/vtd/dmar.h
index 4e66c6c88d..e6cdf62fab 100644
--- a/xen/arch/x86/hvm/vmx/vtd/dmar.h
+++ b/xen/arch/x86/hvm/vmx/vtd/dmar.h
@@ -87,4 +87,6 @@ struct acpi_ioapic_unit {
     }ioapic;
 };
 
+int vtd_hw_check(void);
+
 #endif // _DMAR_H_
diff --git a/xen/arch/x86/hvm/vmx/vtd/utils.c b/xen/arch/x86/hvm/vmx/vtd/utils.c
index 8d575292c3..fa907a544e 100644
--- a/xen/arch/x86/hvm/vmx/vtd/utils.c
+++ b/xen/arch/x86/hvm/vmx/vtd/utils.c
@@ -33,6 +33,37 @@
 #include <xen/mm.h>
 #include <xen/xmalloc.h>
 
+#define VTDPREFIX "[VT-D]" 
+#define INTEL   0x8086
+#define SEABURG 0x4000
+#define C_STEP  2
+
+int vtd_hw_check(void)
+{
+    u16 vendor, device;
+    u8 revision, stepping;
+
+    vendor   = read_pci_config_16(0, 0, 0, PCI_VENDOR_ID);
+    device   = read_pci_config_16(0, 0, 0, PCI_DEVICE_ID);
+    revision = read_pci_config_byte(0, 0, 0, PCI_REVISION_ID);
+    stepping = revision & 0xf;
+
+    if ( (vendor == INTEL) && (device == SEABURG) )
+    {
+        if ( stepping < C_STEP )
+        {
+            dprintk(XENLOG_WARNING VTDPREFIX,
+                    "*** VT-d disabled - pre C0-step Seaburg found\n");
+            dprintk(XENLOG_WARNING VTDPREFIX,
+                    "***  vendor = %x device = %x revision = %x\n",
+                    vendor, device, revision);
+            vtd_enabled = 0;
+            return -ENODEV;
+        }
+    }
+    return 0;
+}
+
 #if defined(__x86_64__)
 void print_iommu_regs(struct acpi_drhd_unit *drhd)
 {