Messages in this thread Patch in this message | | | Date | Thu, 29 Oct 2009 17:27:36 +0900 | Subject | Re: [PATCH 0/10] x86: handle HW IOMMU initialization failure gracely | From | FUJITA Tomonori <> |
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On Wed, 28 Oct 2009 14:21:19 +0100 Joerg Roedel <joerg.roedel@amd.com> wrote:
> > The new x86 IOMMU initialization sequence are: > > > > 1. initializing swiotlb (and setting swiotlb to 1) in the case of > > (max_pfn > MAX_DMA32_PFN && !no_iommu). dma_ops is set to > > swiotlb_dma_ops or nommu_dma_ops. > > > > 2. calling the detection functions of all the IOMMUs > > > > 3. the detection function sets x86_init.iommu.iommu_init to the IOMMU > > initialization function (so we can avoid calling the initialization > > functions of all the IOMMUs needlessly). > > > > 4. if the IOMMU initialization function doesn't need to swiotlb then > > sets swiotlb to zero (e.g. the initialization is sucessful). > > > > 5. if we find that swiotlb is set to zero, we free swiotlb resource. > > I started to test this patchset. It breaks the iommu=soft selection to > force using swiotlb usage. On my machine always the AMD IOMMU driver > gots selected and initialized.
Thanks for testing the patchset.
Sorry about the bug. I need to add 1.5 to the above sequence:
1.5 if swiotlb usage is forced by the boot option, we skip the rest.
Here's a patch against the patchset.
diff --git a/arch/ia64/include/asm/swiotlb.h b/arch/ia64/include/asm/swiotlb.h index dcbaea7..f0acde6 100644 --- a/arch/ia64/include/asm/swiotlb.h +++ b/arch/ia64/include/asm/swiotlb.h @@ -4,8 +4,6 @@ #include <linux/dma-mapping.h> #include <linux/swiotlb.h> -extern int swiotlb_force; - #ifdef CONFIG_SWIOTLB extern int swiotlb; extern void pci_swiotlb_init(void); diff --git a/arch/x86/include/asm/swiotlb.h b/arch/x86/include/asm/swiotlb.h index b9e4e20..193aa75 100644 --- a/arch/x86/include/asm/swiotlb.h +++ b/arch/x86/include/asm/swiotlb.h @@ -5,8 +5,6 @@ /* SWIOTLB interface */ -extern int swiotlb_force; - #ifdef CONFIG_SWIOTLB extern int swiotlb; extern void pci_swiotlb_init(void); diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 28fd54a..2583a0b 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -124,11 +124,15 @@ static void __init dma32_free_bootmem(void) void __init pci_iommu_alloc(void) { + /* swiotlb is forced by the boot option */ + int use_swiotlb = swiotlb; #ifdef CONFIG_X86_64 /* free the range so iommu could get some range less than 4G */ dma32_free_bootmem(); #endif pci_swiotlb_init(); + if (use_swiotlb) + return; gart_iommu_hole_init(); diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c index 607fbb6..17ce422 100644 --- a/arch/x86/kernel/pci-swiotlb.c +++ b/arch/x86/kernel/pci-swiotlb.c @@ -49,8 +49,6 @@ void __init pci_swiotlb_init(void) if (!no_iommu && max_pfn > MAX_DMA32_PFN) swiotlb = 1; #endif - if (swiotlb_force) - swiotlb = 1; if (swiotlb) { swiotlb_init(0); dma_ops = &swiotlb_dma_ops; diff --git a/lib/swiotlb.c b/lib/swiotlb.c index 0c12d7c..2eae139 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -57,7 +57,7 @@ enum dma_sync_target { SYNC_FOR_DEVICE = 1, }; -int swiotlb_force; +static int swiotlb_force; /* * Used to do a quick range check in unmap_single and @@ -109,8 +109,10 @@ setup_io_tlb_npages(char *str) } if (*str == ',') ++str; - if (!strcmp(str, "force")) + if (!strcmp(str, "force")) { swiotlb_force = 1; + swiotlb = 1; + } return 1; } __setup("swiotlb=", setup_io_tlb_npages);
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