linux/arch/x86/kernel/pci-swiotlb.c

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/* Glue code to lib/swiotlb.c */
#include <linux/pci.h>
#include <linux/cache.h>
#include <linux/module.h>
#include <linux/swiotlb.h>
#include <linux/bootmem.h>
#include <linux/dma-mapping.h>
#include <asm/iommu.h>
#include <asm/swiotlb.h>
#include <asm/dma.h>
#include <asm/xen/swiotlb-xen.h>
#include <asm/iommu_table.h>
int swiotlb __read_mostly;
static void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags,
struct dma_attrs *attrs)
{
void *vaddr;
vaddr = dma_generic_alloc_coherent(hwdev, size, dma_handle, flags,
attrs);
if (vaddr)
return vaddr;
return swiotlb_alloc_coherent(hwdev, size, dma_handle, flags);
}
static void x86_swiotlb_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_addr,
struct dma_attrs *attrs)
{
swiotlb_free_coherent(dev, size, vaddr, dma_addr);
}
static struct dma_map_ops swiotlb_dma_ops = {
.mapping_error = swiotlb_dma_mapping_error,
.alloc = x86_swiotlb_alloc_coherent,
.free = x86_swiotlb_free_coherent,
.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
.sync_single_for_device = swiotlb_sync_single_for_device,
.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
.sync_sg_for_device = swiotlb_sync_sg_for_device,
.map_sg = swiotlb_map_sg_attrs,
.unmap_sg = swiotlb_unmap_sg_attrs,
.map_page = swiotlb_map_page,
.unmap_page = swiotlb_unmap_page,
.dma_supported = NULL,
};
/*
* pci_swiotlb_detect_override - set swiotlb to 1 if necessary
*
* This returns non-zero if we are forced to use swiotlb (by the boot
* option).
*/
int __init pci_swiotlb_detect_override(void)
{
int use_swiotlb = swiotlb | swiotlb_force;
if (swiotlb_force)
swiotlb = 1;
return use_swiotlb;
}
IOMMU_INIT_FINISH(pci_swiotlb_detect_override,
pci_xen_swiotlb_detect,
pci_swiotlb_init,
pci_swiotlb_late_init);
/*
* if 4GB or more detected (and iommu=off not set) return 1
* and set swiotlb to 1.
*/
int __init pci_swiotlb_detect_4gb(void)
{
/* don't initialize swiotlb if iommu=off (no_iommu=1) */
#ifdef CONFIG_X86_64
x86: Handle HW IOMMU initialization failure gracefully If HW IOMMU initialization fails (Intel VT-d often does this, typically due to BIOS bugs), we fall back to nommu. It doesn't work for the majority since nowadays we have more than 4GB memory so we must use swiotlb instead of nommu. The problem is that it's too late to initialize swiotlb when HW IOMMU initialization fails. We need to allocate swiotlb memory earlier from bootmem allocator. Chris explained the issue in detail: http://marc.info/?l=linux-kernel&m=125657444317079&w=2 The current x86 IOMMU initialization sequence is too complicated and handling the above issue makes it more hacky. This patch changes x86 IOMMU initialization sequence to handle the above issue cleanly. The new x86 IOMMU initialization sequence are: 1. we initialize the 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. if swiotlb usage is forced by the boot option, we finish here. 2. we call 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. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: chrisw@sous-sol.org Cc: dwmw2@infradead.org Cc: joerg.roedel@amd.com Cc: muli@il.ibm.com LKML-Reference: <1257849980-22640-10-git-send-email-fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-10 10:46:20 +00:00
if (!no_iommu && max_pfn > MAX_DMA32_PFN)
swiotlb = 1;
#endif
return swiotlb;
x86: Split swiotlb initialization into two stages The commit f4780ca005404166cc40af77ef0e86132ab98a81 moves swiotlb initialization before dma32_free_bootmem(). It's supposed to fix a bug that the commit 75f1cdf1dda92cae037ec848ae63690d91913eac introduced, we initialize SWIOTLB right after dma32_free_bootmem so we wrongly steal memory area allocated for GART with broken BIOS earlier. However, the above commit introduced another problem, which likely breaks machines with huge amount of memory. Such a box use the majority of DMA32_ZONE so there is no memory for swiotlb. With this patch, the x86 IOMMU initialization sequence are: 1. We set swiotlb to 1 in the case of (max_pfn > MAX_DMA32_PFN && !no_iommu). If swiotlb usage is forced by the boot option, we go to the step 3 and finish (we don't try to detect IOMMUs). 2. We call the detection functions of all the IOMMUs. 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). 3. We initialize swiotlb (and set dma_ops to swiotlb_dma_ops) if swiotlb is set to 1. 4. If the IOMMU initialization function doesn't need swiotlb (e.g. the initialization is sucessful) then sets swiotlb to zero. 5. If we find that swiotlb is set to zero, we free swiotlb resource. Reported-by: Yinghai Lu <yinghai@kernel.org> Reported-by: Roland Dreier <rdreier@cisco.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> LKML-Reference: <20091215204729A.fujita.tomonori@lab.ntt.co.jp> Tested-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-15 11:47:56 +00:00
}
IOMMU_INIT(pci_swiotlb_detect_4gb,
pci_swiotlb_detect_override,
pci_swiotlb_init,
pci_swiotlb_late_init);
x86: Split swiotlb initialization into two stages The commit f4780ca005404166cc40af77ef0e86132ab98a81 moves swiotlb initialization before dma32_free_bootmem(). It's supposed to fix a bug that the commit 75f1cdf1dda92cae037ec848ae63690d91913eac introduced, we initialize SWIOTLB right after dma32_free_bootmem so we wrongly steal memory area allocated for GART with broken BIOS earlier. However, the above commit introduced another problem, which likely breaks machines with huge amount of memory. Such a box use the majority of DMA32_ZONE so there is no memory for swiotlb. With this patch, the x86 IOMMU initialization sequence are: 1. We set swiotlb to 1 in the case of (max_pfn > MAX_DMA32_PFN && !no_iommu). If swiotlb usage is forced by the boot option, we go to the step 3 and finish (we don't try to detect IOMMUs). 2. We call the detection functions of all the IOMMUs. 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). 3. We initialize swiotlb (and set dma_ops to swiotlb_dma_ops) if swiotlb is set to 1. 4. If the IOMMU initialization function doesn't need swiotlb (e.g. the initialization is sucessful) then sets swiotlb to zero. 5. If we find that swiotlb is set to zero, we free swiotlb resource. Reported-by: Yinghai Lu <yinghai@kernel.org> Reported-by: Roland Dreier <rdreier@cisco.com> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> LKML-Reference: <20091215204729A.fujita.tomonori@lab.ntt.co.jp> Tested-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-15 11:47:56 +00:00
void __init pci_swiotlb_init(void)
{
if (swiotlb) {
swiotlb_init(0);
dma_ops = &swiotlb_dma_ops;
}
}
void __init pci_swiotlb_late_init(void)
{
/* An IOMMU turned us off. */
if (!swiotlb)
swiotlb_free();
else {
printk(KERN_INFO "PCI-DMA: "
"Using software bounce buffering for IO (SWIOTLB)\n");
swiotlb_print_info();
}
}