Commit 58d11317 authored by Olof Johansson's avatar Olof Johansson Committed by Joerg Roedel
Browse files

iommu: Add config option to set passthrough as default 



This allows the default behavior to be controlled by a kernel config
option instead of changing the commandline for the kernel to include
"iommu.passthrough=on" or "iommu=pt" on machines where this is desired.

Likewise, for machines where this config option is enabled, it can be
disabled at boot time with "iommu.passthrough=off" or "iommu=nopt".

Also corrected iommu=pt documentation for IA-64, since it has no code that
parses iommu= at all.

Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent c52c72d3

Documentation/admin-guide/kernel-parameters.txt

+2 −1
Original line number Diff line number Diff line
@@ -1716,7 +1716,8 @@ 
		merge

		nomerge

		soft

		pt		[x86, IA-64]

		pt		[x86]

		nopt		[x86]

		nobypass	[PPC/POWERNV]

			Disable IOMMU bypass, using IOMMU for PCI devices.

arch/x86/kernel/pci-dma.c

+8 −0
Original line number Diff line number Diff line
@@ -40,8 +40,14 @@ int iommu_detected __read_mostly = 0; 
 * devices and allow every device to access to whole physical memory. This is

 * useful if a user wants to use an IOMMU only for KVM device assignment to

 * guests and not for driver dma translation.

 * It is also possible to disable by default in kernel config, and enable with

 * iommu=nopt at boot time.

 */

#ifdef CONFIG_IOMMU_DEFAULT_PASSTHROUGH

int iommu_pass_through __read_mostly = 1;

#else

int iommu_pass_through __read_mostly;

#endif



extern struct iommu_table_entry __iommu_table[], __iommu_table_end[];
@@ -135,6 +141,8 @@ static __init int iommu_setup(char *p) 
#endif

		if (!strncmp(p, "pt", 2))

			iommu_pass_through = 1;

		if (!strncmp(p, "nopt", 4))

			iommu_pass_through = 0;



		gart_parse_options(p);

drivers/iommu/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -70,6 +70,17 @@ config IOMMU_DEBUGFS 
	  debug/iommu directory, and then populate a subdirectory with

	  entries as required.



config IOMMU_DEFAULT_PASSTHROUGH

	bool "IOMMU passthrough by default"

	depends on IOMMU_API

        help

	  Enable passthrough by default, removing the need to pass in

	  iommu.passthrough=on or iommu=pt through command line. If this

	  is enabled, you can still disable with iommu.passthrough=off

	  or iommu=nopt depending on the architecture.



	  If unsure, say N here.



config IOMMU_IOVA

	tristate

drivers/iommu/iommu.c

+4 −0
Original line number Diff line number Diff line
@@ -36,7 +36,11 @@ 


static struct kset *iommu_group_kset;

static DEFINE_IDA(iommu_group_ida);

#ifdef CONFIG_IOMMU_DEFAULT_PASSTHROUGH

static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_IDENTITY;

#else

static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_DMA;

#endif



struct iommu_callback_data {

	const struct iommu_ops *ops;

CRA Git | Maintained and supported by SUSTech CRA and CCSE