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Commit 65f87d8a authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
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[PATCH] x86_64: Fix swiotlb=force 



It was broken before. But having it is important as possible hardware
bug workaround.

And previously there was no way to force swiotlb if there is another IOMMU.
Side effect is that iommu=force won't force swiotlb anymore even if there
isn't another IOMMU.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 355540f3

arch/x86_64/kernel/pci-swiotlb.c

+3 −2
Original line number Diff line number Diff line
@@ -31,8 +31,9 @@ struct dma_mapping_ops swiotlb_dma_ops = { 
void pci_swiotlb_init(void)

{

	/* don't initialize swiotlb if iommu=off (no_iommu=1) */

	if (!iommu_detected && !no_iommu &&

	    (end_pfn > MAX_DMA32_PFN || force_iommu))

	if (!iommu_detected && !no_iommu && end_pfn > MAX_DMA32_PFN)

	       swiotlb = 1;

	if (swiotlb_force)

		swiotlb = 1;

	if (swiotlb) {

		printk(KERN_INFO "PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");

include/asm-x86_64/swiotlb.h

+2 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ extern void swiotlb_free_coherent (struct device *hwdev, size_t size, 
extern int swiotlb_dma_supported(struct device *hwdev, u64 mask);

extern void swiotlb_init(void);



extern int swiotlb_force;



#ifdef CONFIG_SWIOTLB

extern int swiotlb;

#else