Messages in this thread | | | Date | Fri, 21 Dec 2012 21:18:13 -0500 | From | Konrad Rzeszutek Wilk <> | Subject | Re: [PATCH v6 24/27] x86: Add swiotlb force off support |
| |
On Thu, Dec 13, 2012 at 02:02:18PM -0800, Yinghai Lu wrote: > 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.
Does this have any usage besides testing?
And also pls in the future use scripts/get_maintainer.pl so that you can extract from the email of the maintainer (which would be me).
> > 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
| |