Messages in this thread Patch in this message | | | From | Yinghai Lu <> | Subject | [PATCH v6 24/27] x86: Add swiotlb force off support | Date | Thu, 13 Dec 2012 14:02:18 -0800 |
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So use could disable swiotlb from command line, even swiotlb support is compiled in. Just like we have intel_iommu=on and intel_iommu=off.
Signed-off-by: Yinghai Lu <yinghai@kernel.org> --- Documentation/kernel-parameters.txt | 7 +++++++ arch/x86/kernel/pci-swiotlb.c | 10 +++++----- drivers/iommu/amd_iommu.c | 1 + include/linux/swiotlb.h | 1 + lib/swiotlb.c | 5 ++++- 5 files changed, 18 insertions(+), 6 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 20e248c..08b4c9d 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2832,6 +2832,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. swiotlb= [IA-64] Number of I/O TLB slabs + swiotlb=[force|off|on] [KNL] disable or enable swiotlb. + force + on + Enable swiotlb. + off + Disable swiotlb. + switches= [HW,M68k] sysfs.deprecated=0|1 [KNL] diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c index 6f93eb7..80afd3b 100644 --- a/arch/x86/kernel/pci-swiotlb.c +++ b/arch/x86/kernel/pci-swiotlb.c @@ -58,12 +58,12 @@ static struct dma_map_ops swiotlb_dma_ops = { */ int __init pci_swiotlb_detect_override(void) { - int use_swiotlb = swiotlb | swiotlb_force; - if (swiotlb_force) swiotlb = 1; + else if (swiotlb_force_off) + swiotlb = 0; - return use_swiotlb; + return swiotlb; } IOMMU_INIT_FINISH(pci_swiotlb_detect_override, pci_xen_swiotlb_detect, @@ -76,9 +76,9 @@ IOMMU_INIT_FINISH(pci_swiotlb_detect_override, */ int __init pci_swiotlb_detect_4gb(void) { - /* don't initialize swiotlb if iommu=off (no_iommu=1) */ + /* don't initialize swiotlb if iommu=off (no_iommu=1) or force off */ #ifdef CONFIG_X86_64 - if (!no_iommu && max_pfn > MAX_DMA32_PFN) + if (!no_iommu && !swiotlb_force_off && max_pfn > MAX_DMA32_PFN) swiotlb = 1; #endif return swiotlb; diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 55074cb..4f370d3 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -3082,6 +3082,7 @@ int __init amd_iommu_init_dma_ops(void) unhandled = device_dma_ops_init(); if (unhandled && max_pfn > MAX_DMA32_PFN) { /* There are unhandled devices - initialize swiotlb for them */ + WARN(swiotlb_force_off, "Please remove swiotlb=off\n"); swiotlb = 1; } diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index f7535d1..dd7cf65 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -8,6 +8,7 @@ struct dma_attrs; struct scatterlist; extern int swiotlb_force; +extern int swiotlb_force_off; /* * Maximum allowable number of contiguous slabs to map, diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 6b99ea7..3f51b2c 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -51,6 +51,7 @@ #define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) int swiotlb_force; +int swiotlb_force_off; /* * Used to do a quick range check in swiotlb_tbl_unmap_single and @@ -102,8 +103,10 @@ setup_io_tlb_npages(char *str) } if (*str == ',') ++str; - if (!strcmp(str, "force")) + if (!strcmp(str, "force") || !strcmp(str, "on")) swiotlb_force = 1; + if (!strcmp(str, "off")) + swiotlb_force_off = 1; return 1; } -- 1.7.10.4
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