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Commit 0cd5c3c8 authored by Kyle McMartin's avatar Kyle McMartin Committed by Ingo Molnar
Browse files

x86: disable intel_iommu support by default 

Due to recurring issues with DMAR support on certain platforms.
There's a number of filesystem corruption incidents reported:

  https://bugzilla.redhat.com/show_bug.cgi?id=479996
  http://bugzilla.kernel.org/show_bug.cgi?id=12578



Provide a Kconfig option to change whether it is enabled by
default.

If disabled, it can still be reenabled by passing intel_iommu=on to the
kernel. Keep the .config option off by default.

Signed-off-by: default avatarKyle McMartin <kyle@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-By: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b534816b

Documentation/kernel-parameters.txt

+2 −0
Original line number Diff line number Diff line
@@ -937,6 +937,8 @@ and is between 256 and 4096 characters. It is defined in the file 




	intel_iommu=	[DMAR] Intel IOMMU driver (DMAR) option

		on

			Enable intel iommu driver.

		off

			Disable intel iommu driver.

		igfx_off [Default Off]

arch/x86/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -1802,6 +1802,17 @@ config DMAR 
	  and include PCI device scope covered by these DMA

	  remapping devices.



config DMAR_DEFAULT_ON

	def_bool n

	prompt "Enable DMA Remapping Devices by default"

	depends on DMAR

	help

	  Selecting this option will enable a DMAR device at boot time if

	  one is found. If this option is not selected, DMAR support can

	  be enabled by passing intel_iommu=on to the kernel. It is

	  recommended you say N here while the DMAR code remains

	  experimental.



config DMAR_GFX_WA

	def_bool y

	prompt "Support for Graphics workaround"

drivers/pci/intel-iommu.c

+11 −3
Original line number Diff line number Diff line
@@ -268,7 +268,12 @@ static long list_size; 


static void domain_remove_dev_info(struct dmar_domain *domain);



int dmar_disabled;

#ifdef CONFIG_DMAR_DEFAULT_ON

int dmar_disabled = 0;

#else

int dmar_disabled = 1;

#endif /*CONFIG_DMAR_DEFAULT_ON*/



static int __initdata dmar_map_gfx = 1;

static int dmar_forcedac;

static int intel_iommu_strict;
@@ -284,7 +289,10 @@ static int __init intel_iommu_setup(char *str) 
	if (!str)

		return -EINVAL;

	while (*str) {

		if (!strncmp(str, "off", 3)) {

		if (!strncmp(str, "on", 2)) {

			dmar_disabled = 0;

			printk(KERN_INFO "Intel-IOMMU: enabled\n");

		} else if (!strncmp(str, "off", 3)) {

			dmar_disabled = 1;

			printk(KERN_INFO "Intel-IOMMU: disabled\n");

		} else if (!strncmp(str, "igfx_off", 8)) {