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| author | Olof Johansson <olof@lixom.net> | 2018-07-20 11:02:23 -0700 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2018-07-27 09:36:50 +0200 |
| commit | 58d1131777a4b7c228267b809bd88f7be66edcfb (patch) | |
| tree | 915247adf72282f7594fb17bfcfef6307754a5cb /arch | |
| parent | c52c72d3dee81af893cee0414444818ed91e2e11 (diff) | |
| download | linux-58d1131777a4b7c228267b809bd88f7be66edcfb.tar.gz linux-58d1131777a4b7c228267b809bd88f7be66edcfb.tar.bz2 linux-58d1131777a4b7c228267b809bd88f7be66edcfb.zip | |
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: Olof Johansson <olof@lixom.net>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/pci-dma.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index ab5d9dd668d2..0acb135de7fb 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -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); |