[PATCH] x86: Disable MMCONFIG on Intel SDV using DMI blacklist

As a replacement for the earlier removal of the e820 MCFG check
we blacklist the Intel SDV with the original BIOS bug that
motivated that check. On those machines don't use MMCONFIG.

This also adds a new pci=mmconf parameter to override the blacklist.

Cc: Greg KH <gregkh@suse.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/kernel-parameters.txt

@@ -1183,6 +1183,8 @@ running once the system is up.
 				Mechanism 2.
 		nommconf	[IA-32,X86_64] Disable use of MMCONFIG for PCI
 				Configuration
+		mmconf		[IA-32,X86_64] Force MMCONFIG. This is useful
+				to override the builtin blacklist.
 		nomsi		[MSI] If the PCI_MSI kernel config parameter is
 				enabled, this kernel boot option can be used to
 				disable the use of MSI interrupts system-wide.

arch/i386/pci/common.c

@@ -237,6 +237,11 @@ char * __devinit  pcibios_setup(char *str)
 		pci_probe &= ~PCI_PROBE_MMCONF;
 		return NULL;
 	}
+	/* override DMI blacklist */
+	else if (!strcmp(str, "mmconf")) {
+		pci_probe |= PCI_PROBE_MMCONF_FORCE;
+		return NULL;
+	}
 #endif
 	else if (!strcmp(str, "noacpi")) {
 		acpi_noirq_set();

arch/i386/pci/mmconfig.c

@@ -12,6 +12,7 @@
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/dmi.h>
 #include <asm/e820.h>
 #include "pci.h"
 
@@ -187,9 +188,31 @@ static __init void unreachable_devices(void)
 	}
 }
 
+static int disable_mcfg(struct dmi_system_id *d)
+{
+	printk("PCI: %s detected. Disabling MCFG.\n", d->ident);
+	pci_probe &= ~PCI_PROBE_MMCONF;
+	return 0;
+}
+
+static struct dmi_system_id __initdata dmi_bad_mcfg[] = {
+	/* Has broken MCFG table that makes the system hang when used */
+        {
+         .callback = disable_mcfg,
+         .ident = "Intel D3C5105 SDV",
+         .matches = {
+                     DMI_MATCH(DMI_BIOS_VENDOR, "Intel"),
+                     DMI_MATCH(DMI_BOARD_NAME, "D26928"),
+                     },
+         },
+         {}
+};
+
 void __init pci_mmcfg_init(void)
 {
-	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
+	dmi_check_system(dmi_bad_mcfg);
+
+	if ((pci_probe & (PCI_PROBE_MMCONF_FORCE|PCI_PROBE_MMCONF)) == 0)
 		return;
 
 	acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg);

arch/i386/pci/pci.h

@@ -16,7 +16,8 @@
 #define PCI_PROBE_CONF1		0x0002
 #define PCI_PROBE_CONF2		0x0004
 #define PCI_PROBE_MMCONF	0x0008
-#define PCI_PROBE_MASK		0x000f
+#define PCI_PROBE_MMCONF_FORCE	0x0010
+#define PCI_PROBE_MASK		0x00ff
 
 #define PCI_NO_SORT		0x0100
 #define PCI_BIOS_SORT		0x0200

arch/x86_64/pci/mmconfig.c

@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
+#include <linux/dmi.h>
 #include <asm/e820.h>
 
 #include "pci.h"
@@ -164,11 +165,33 @@ static __init void unreachable_devices(void)
 	}
 }
 
+static int disable_mcfg(struct dmi_system_id *d)
+{
+	printk("PCI: %s detected. Disabling MCFG.\n", d->ident);
+	pci_probe &= ~PCI_PROBE_MMCONF;
+	return 0;
+}
+
+static struct dmi_system_id __initdata dmi_bad_mcfg[] = {
+	/* Has broken MCFG table that makes the system hang when used */
+        {
+         .callback = disable_mcfg,
+         .ident = "Intel D3C5105 SDV",
+         .matches = {
+                     DMI_MATCH(DMI_BIOS_VENDOR, "Intel"),
+                     DMI_MATCH(DMI_BOARD_NAME, "D26928"),
+                     },
+         },
+         {}
+};
+
 void __init pci_mmcfg_init(void)
 {
 	int i;
 
-	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
+	dmi_check_system(dmi_bad_mcfg);
+
+	if ((pci_probe & (PCI_PROBE_MMCONF|PCI_PROBE_MMCONF_FORCE)) == 0)
 		return;
 
 	acpi_table_parse(ACPI_MCFG, acpi_parse_mcfg);