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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/drivers/xen/swiotlb-xen.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/drivers/xen/swiotlb-xen.c')
-rw-r--r--kernel/drivers/xen/swiotlb-xen.c688
1 files changed, 688 insertions, 0 deletions
diff --git a/kernel/drivers/xen/swiotlb-xen.c b/kernel/drivers/xen/swiotlb-xen.c
new file mode 100644
index 000000000..4c549323c
--- /dev/null
+++ b/kernel/drivers/xen/swiotlb-xen.c
@@ -0,0 +1,688 @@
+/*
+ * Copyright 2010
+ * by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ *
+ * This code provides a IOMMU for Xen PV guests with PCI passthrough.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License v2.0 as published by
+ * the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * PV guests under Xen are running in an non-contiguous memory architecture.
+ *
+ * When PCI pass-through is utilized, this necessitates an IOMMU for
+ * translating bus (DMA) to virtual and vice-versa and also providing a
+ * mechanism to have contiguous pages for device drivers operations (say DMA
+ * operations).
+ *
+ * Specifically, under Xen the Linux idea of pages is an illusion. It
+ * assumes that pages start at zero and go up to the available memory. To
+ * help with that, the Linux Xen MMU provides a lookup mechanism to
+ * translate the page frame numbers (PFN) to machine frame numbers (MFN)
+ * and vice-versa. The MFN are the "real" frame numbers. Furthermore
+ * memory is not contiguous. Xen hypervisor stitches memory for guests
+ * from different pools, which means there is no guarantee that PFN==MFN
+ * and PFN+1==MFN+1. Lastly with Xen 4.0, pages (in debug mode) are
+ * allocated in descending order (high to low), meaning the guest might
+ * never get any MFN's under the 4GB mark.
+ *
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/bootmem.h>
+#include <linux/dma-mapping.h>
+#include <linux/export.h>
+#include <xen/swiotlb-xen.h>
+#include <xen/page.h>
+#include <xen/xen-ops.h>
+#include <xen/hvc-console.h>
+
+#include <asm/dma-mapping.h>
+#include <asm/xen/page-coherent.h>
+
+#include <trace/events/swiotlb.h>
+/*
+ * Used to do a quick range check in swiotlb_tbl_unmap_single and
+ * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this
+ * API.
+ */
+
+#ifndef CONFIG_X86
+static unsigned long dma_alloc_coherent_mask(struct device *dev,
+ gfp_t gfp)
+{
+ unsigned long dma_mask = 0;
+
+ dma_mask = dev->coherent_dma_mask;
+ if (!dma_mask)
+ dma_mask = (gfp & GFP_DMA) ? DMA_BIT_MASK(24) : DMA_BIT_MASK(32);
+
+ return dma_mask;
+}
+#endif
+
+static char *xen_io_tlb_start, *xen_io_tlb_end;
+static unsigned long xen_io_tlb_nslabs;
+/*
+ * Quick lookup value of the bus address of the IOTLB.
+ */
+
+static u64 start_dma_addr;
+
+/*
+ * Both of these functions should avoid PFN_PHYS because phys_addr_t
+ * can be 32bit when dma_addr_t is 64bit leading to a loss in
+ * information if the shift is done before casting to 64bit.
+ */
+static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr)
+{
+ unsigned long mfn = pfn_to_mfn(PFN_DOWN(paddr));
+ dma_addr_t dma = (dma_addr_t)mfn << PAGE_SHIFT;
+
+ dma |= paddr & ~PAGE_MASK;
+
+ return dma;
+}
+
+static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
+{
+ unsigned long pfn = mfn_to_pfn(PFN_DOWN(baddr));
+ dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT;
+ phys_addr_t paddr = dma;
+
+ paddr |= baddr & ~PAGE_MASK;
+
+ return paddr;
+}
+
+static inline dma_addr_t xen_virt_to_bus(void *address)
+{
+ return xen_phys_to_bus(virt_to_phys(address));
+}
+
+static int check_pages_physically_contiguous(unsigned long pfn,
+ unsigned int offset,
+ size_t length)
+{
+ unsigned long next_mfn;
+ int i;
+ int nr_pages;
+
+ next_mfn = pfn_to_mfn(pfn);
+ nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT;
+
+ for (i = 1; i < nr_pages; i++) {
+ if (pfn_to_mfn(++pfn) != ++next_mfn)
+ return 0;
+ }
+ return 1;
+}
+
+static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
+{
+ unsigned long pfn = PFN_DOWN(p);
+ unsigned int offset = p & ~PAGE_MASK;
+
+ if (offset + size <= PAGE_SIZE)
+ return 0;
+ if (check_pages_physically_contiguous(pfn, offset, size))
+ return 0;
+ return 1;
+}
+
+static int is_xen_swiotlb_buffer(dma_addr_t dma_addr)
+{
+ unsigned long mfn = PFN_DOWN(dma_addr);
+ unsigned long pfn = mfn_to_local_pfn(mfn);
+ phys_addr_t paddr;
+
+ /* If the address is outside our domain, it CAN
+ * have the same virtual address as another address
+ * in our domain. Therefore _only_ check address within our domain.
+ */
+ if (pfn_valid(pfn)) {
+ paddr = PFN_PHYS(pfn);
+ return paddr >= virt_to_phys(xen_io_tlb_start) &&
+ paddr < virt_to_phys(xen_io_tlb_end);
+ }
+ return 0;
+}
+
+static int max_dma_bits = 32;
+
+static int
+xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
+{
+ int i, rc;
+ int dma_bits;
+ dma_addr_t dma_handle;
+ phys_addr_t p = virt_to_phys(buf);
+
+ dma_bits = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT) + PAGE_SHIFT;
+
+ i = 0;
+ do {
+ int slabs = min(nslabs - i, (unsigned long)IO_TLB_SEGSIZE);
+
+ do {
+ rc = xen_create_contiguous_region(
+ p + (i << IO_TLB_SHIFT),
+ get_order(slabs << IO_TLB_SHIFT),
+ dma_bits, &dma_handle);
+ } while (rc && dma_bits++ < max_dma_bits);
+ if (rc)
+ return rc;
+
+ i += slabs;
+ } while (i < nslabs);
+ return 0;
+}
+static unsigned long xen_set_nslabs(unsigned long nr_tbl)
+{
+ if (!nr_tbl) {
+ xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+ xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+ } else
+ xen_io_tlb_nslabs = nr_tbl;
+
+ return xen_io_tlb_nslabs << IO_TLB_SHIFT;
+}
+
+enum xen_swiotlb_err {
+ XEN_SWIOTLB_UNKNOWN = 0,
+ XEN_SWIOTLB_ENOMEM,
+ XEN_SWIOTLB_EFIXUP
+};
+
+static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
+{
+ switch (err) {
+ case XEN_SWIOTLB_ENOMEM:
+ return "Cannot allocate Xen-SWIOTLB buffer\n";
+ case XEN_SWIOTLB_EFIXUP:
+ return "Failed to get contiguous memory for DMA from Xen!\n"\
+ "You either: don't have the permissions, do not have"\
+ " enough free memory under 4GB, or the hypervisor memory"\
+ " is too fragmented!";
+ default:
+ break;
+ }
+ return "";
+}
+int __ref xen_swiotlb_init(int verbose, bool early)
+{
+ unsigned long bytes, order;
+ int rc = -ENOMEM;
+ enum xen_swiotlb_err m_ret = XEN_SWIOTLB_UNKNOWN;
+ unsigned int repeat = 3;
+
+ xen_io_tlb_nslabs = swiotlb_nr_tbl();
+retry:
+ bytes = xen_set_nslabs(xen_io_tlb_nslabs);
+ order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
+ /*
+ * Get IO TLB memory from any location.
+ */
+ if (early)
+ xen_io_tlb_start = alloc_bootmem_pages(PAGE_ALIGN(bytes));
+ else {
+#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
+#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
+ while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
+ xen_io_tlb_start = (void *)xen_get_swiotlb_free_pages(order);
+ if (xen_io_tlb_start)
+ break;
+ order--;
+ }
+ if (order != get_order(bytes)) {
+ pr_warn("Warning: only able to allocate %ld MB for software IO TLB\n",
+ (PAGE_SIZE << order) >> 20);
+ xen_io_tlb_nslabs = SLABS_PER_PAGE << order;
+ bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
+ }
+ }
+ if (!xen_io_tlb_start) {
+ m_ret = XEN_SWIOTLB_ENOMEM;
+ goto error;
+ }
+ xen_io_tlb_end = xen_io_tlb_start + bytes;
+ /*
+ * And replace that memory with pages under 4GB.
+ */
+ rc = xen_swiotlb_fixup(xen_io_tlb_start,
+ bytes,
+ xen_io_tlb_nslabs);
+ if (rc) {
+ if (early)
+ free_bootmem(__pa(xen_io_tlb_start), PAGE_ALIGN(bytes));
+ else {
+ free_pages((unsigned long)xen_io_tlb_start, order);
+ xen_io_tlb_start = NULL;
+ }
+ m_ret = XEN_SWIOTLB_EFIXUP;
+ goto error;
+ }
+ start_dma_addr = xen_virt_to_bus(xen_io_tlb_start);
+ if (early) {
+ if (swiotlb_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs,
+ verbose))
+ panic("Cannot allocate SWIOTLB buffer");
+ rc = 0;
+ } else
+ rc = swiotlb_late_init_with_tbl(xen_io_tlb_start, xen_io_tlb_nslabs);
+ return rc;
+error:
+ if (repeat--) {
+ xen_io_tlb_nslabs = max(1024UL, /* Min is 2MB */
+ (xen_io_tlb_nslabs >> 1));
+ pr_info("Lowering to %luMB\n",
+ (xen_io_tlb_nslabs << IO_TLB_SHIFT) >> 20);
+ goto retry;
+ }
+ pr_err("%s (rc:%d)\n", xen_swiotlb_error(m_ret), rc);
+ if (early)
+ panic("%s (rc:%d)", xen_swiotlb_error(m_ret), rc);
+ else
+ free_pages((unsigned long)xen_io_tlb_start, order);
+ return rc;
+}
+void *
+xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flags,
+ struct dma_attrs *attrs)
+{
+ void *ret;
+ int order = get_order(size);
+ u64 dma_mask = DMA_BIT_MASK(32);
+ phys_addr_t phys;
+ dma_addr_t dev_addr;
+
+ /*
+ * Ignore region specifiers - the kernel's ideas of
+ * pseudo-phys memory layout has nothing to do with the
+ * machine physical layout. We can't allocate highmem
+ * because we can't return a pointer to it.
+ */
+ flags &= ~(__GFP_DMA | __GFP_HIGHMEM);
+
+ if (dma_alloc_from_coherent(hwdev, size, dma_handle, &ret))
+ return ret;
+
+ /* On ARM this function returns an ioremap'ped virtual address for
+ * which virt_to_phys doesn't return the corresponding physical
+ * address. In fact on ARM virt_to_phys only works for kernel direct
+ * mapped RAM memory. Also see comment below.
+ */
+ ret = xen_alloc_coherent_pages(hwdev, size, dma_handle, flags, attrs);
+
+ if (!ret)
+ return ret;
+
+ if (hwdev && hwdev->coherent_dma_mask)
+ dma_mask = dma_alloc_coherent_mask(hwdev, flags);
+
+ /* At this point dma_handle is the physical address, next we are
+ * going to set it to the machine address.
+ * Do not use virt_to_phys(ret) because on ARM it doesn't correspond
+ * to *dma_handle. */
+ phys = *dma_handle;
+ dev_addr = xen_phys_to_bus(phys);
+ if (((dev_addr + size - 1 <= dma_mask)) &&
+ !range_straddles_page_boundary(phys, size))
+ *dma_handle = dev_addr;
+ else {
+ if (xen_create_contiguous_region(phys, order,
+ fls64(dma_mask), dma_handle) != 0) {
+ xen_free_coherent_pages(hwdev, size, ret, (dma_addr_t)phys, attrs);
+ return NULL;
+ }
+ }
+ memset(ret, 0, size);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
+
+void
+xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
+ dma_addr_t dev_addr, struct dma_attrs *attrs)
+{
+ int order = get_order(size);
+ phys_addr_t phys;
+ u64 dma_mask = DMA_BIT_MASK(32);
+
+ if (dma_release_from_coherent(hwdev, order, vaddr))
+ return;
+
+ if (hwdev && hwdev->coherent_dma_mask)
+ dma_mask = hwdev->coherent_dma_mask;
+
+ /* do not use virt_to_phys because on ARM it doesn't return you the
+ * physical address */
+ phys = xen_bus_to_phys(dev_addr);
+
+ if (((dev_addr + size - 1 > dma_mask)) ||
+ range_straddles_page_boundary(phys, size))
+ xen_destroy_contiguous_region(phys, order);
+
+ xen_free_coherent_pages(hwdev, size, vaddr, (dma_addr_t)phys, attrs);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
+
+
+/*
+ * Map a single buffer of the indicated size for DMA in streaming mode. The
+ * physical address to use is returned.
+ *
+ * Once the device is given the dma address, the device owns this memory until
+ * either xen_swiotlb_unmap_page or xen_swiotlb_dma_sync_single is performed.
+ */
+dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
+ unsigned long offset, size_t size,
+ enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ phys_addr_t map, phys = page_to_phys(page) + offset;
+ dma_addr_t dev_addr = xen_phys_to_bus(phys);
+
+ BUG_ON(dir == DMA_NONE);
+ /*
+ * If the address happens to be in the device's DMA window,
+ * we can safely return the device addr and not worry about bounce
+ * buffering it.
+ */
+ if (dma_capable(dev, dev_addr, size) &&
+ !range_straddles_page_boundary(phys, size) &&
+ !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) &&
+ !swiotlb_force) {
+ /* we are not interested in the dma_addr returned by
+ * xen_dma_map_page, only in the potential cache flushes executed
+ * by the function. */
+ xen_dma_map_page(dev, page, dev_addr, offset, size, dir, attrs);
+ return dev_addr;
+ }
+
+ /*
+ * Oh well, have to allocate and map a bounce buffer.
+ */
+ trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
+
+ map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
+ if (map == SWIOTLB_MAP_ERROR)
+ return DMA_ERROR_CODE;
+
+ xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
+ dev_addr, map & ~PAGE_MASK, size, dir, attrs);
+ dev_addr = xen_phys_to_bus(map);
+
+ /*
+ * Ensure that the address returned is DMA'ble
+ */
+ if (!dma_capable(dev, dev_addr, size)) {
+ swiotlb_tbl_unmap_single(dev, map, size, dir);
+ dev_addr = 0;
+ }
+ return dev_addr;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
+
+/*
+ * Unmap a single streaming mode DMA translation. The dma_addr and size must
+ * match what was provided for in a previous xen_swiotlb_map_page call. All
+ * other usages are undefined.
+ *
+ * After this call, reads by the cpu to the buffer are guaranteed to see
+ * whatever the device wrote there.
+ */
+static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ phys_addr_t paddr = xen_bus_to_phys(dev_addr);
+
+ BUG_ON(dir == DMA_NONE);
+
+ xen_dma_unmap_page(hwdev, dev_addr, size, dir, attrs);
+
+ /* NOTE: We use dev_addr here, not paddr! */
+ if (is_xen_swiotlb_buffer(dev_addr)) {
+ swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
+ return;
+ }
+
+ if (dir != DMA_FROM_DEVICE)
+ return;
+
+ /*
+ * phys_to_virt doesn't work with hihgmem page but we could
+ * call dma_mark_clean() with hihgmem page here. However, we
+ * are fine since dma_mark_clean() is null on POWERPC. We can
+ * make dma_mark_clean() take a physical address if necessary.
+ */
+ dma_mark_clean(phys_to_virt(paddr), size);
+}
+
+void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_page);
+
+/*
+ * Make physical memory consistent for a single streaming mode DMA translation
+ * after a transfer.
+ *
+ * If you perform a xen_swiotlb_map_page() but wish to interrogate the buffer
+ * using the cpu, yet do not wish to teardown the dma mapping, you must
+ * call this function before doing so. At the next point you give the dma
+ * address back to the card, you must first perform a
+ * xen_swiotlb_dma_sync_for_device, and then the device again owns the buffer
+ */
+static void
+xen_swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir,
+ enum dma_sync_target target)
+{
+ phys_addr_t paddr = xen_bus_to_phys(dev_addr);
+
+ BUG_ON(dir == DMA_NONE);
+
+ if (target == SYNC_FOR_CPU)
+ xen_dma_sync_single_for_cpu(hwdev, dev_addr, size, dir);
+
+ /* NOTE: We use dev_addr here, not paddr! */
+ if (is_xen_swiotlb_buffer(dev_addr))
+ swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target);
+
+ if (target == SYNC_FOR_DEVICE)
+ xen_dma_sync_single_for_device(hwdev, dev_addr, size, dir);
+
+ if (dir != DMA_FROM_DEVICE)
+ return;
+
+ dma_mark_clean(phys_to_virt(paddr), size);
+}
+
+void
+xen_swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_cpu);
+
+void
+xen_swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
+ size_t size, enum dma_data_direction dir)
+{
+ xen_swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
+
+/*
+ * Map a set of buffers described by scatterlist in streaming mode for DMA.
+ * This is the scatter-gather version of the above xen_swiotlb_map_page
+ * interface. Here the scatter gather list elements are each tagged with the
+ * appropriate dma address and length. They are obtained via
+ * sg_dma_{address,length}(SG).
+ *
+ * NOTE: An implementation may be able to use a smaller number of
+ * DMA address/length pairs than there are SG table elements.
+ * (for example via virtual mapping capabilities)
+ * The routine returns the number of addr/length pairs actually
+ * used, at most nents.
+ *
+ * Device ownership issues as mentioned above for xen_swiotlb_map_page are the
+ * same here.
+ */
+int
+xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for_each_sg(sgl, sg, nelems, i) {
+ phys_addr_t paddr = sg_phys(sg);
+ dma_addr_t dev_addr = xen_phys_to_bus(paddr);
+
+ if (swiotlb_force ||
+ xen_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) ||
+ !dma_capable(hwdev, dev_addr, sg->length) ||
+ range_straddles_page_boundary(paddr, sg->length)) {
+ phys_addr_t map = swiotlb_tbl_map_single(hwdev,
+ start_dma_addr,
+ sg_phys(sg),
+ sg->length,
+ dir);
+ if (map == SWIOTLB_MAP_ERROR) {
+ dev_warn(hwdev, "swiotlb buffer is full\n");
+ /* Don't panic here, we expect map_sg users
+ to do proper error handling. */
+ xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
+ attrs);
+ sg_dma_len(sgl) = 0;
+ return 0;
+ }
+ xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
+ dev_addr,
+ map & ~PAGE_MASK,
+ sg->length,
+ dir,
+ attrs);
+ sg->dma_address = xen_phys_to_bus(map);
+ } else {
+ /* we are not interested in the dma_addr returned by
+ * xen_dma_map_page, only in the potential cache flushes executed
+ * by the function. */
+ xen_dma_map_page(hwdev, pfn_to_page(paddr >> PAGE_SHIFT),
+ dev_addr,
+ paddr & ~PAGE_MASK,
+ sg->length,
+ dir,
+ attrs);
+ sg->dma_address = dev_addr;
+ }
+ sg_dma_len(sg) = sg->length;
+ }
+ return nelems;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
+
+/*
+ * Unmap a set of streaming mode DMA translations. Again, cpu read rules
+ * concerning calls here are the same as for swiotlb_unmap_page() above.
+ */
+void
+xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ struct dma_attrs *attrs)
+{
+ struct scatterlist *sg;
+ int i;
+
+ BUG_ON(dir == DMA_NONE);
+
+ for_each_sg(sgl, sg, nelems, i)
+ xen_unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, attrs);
+
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_unmap_sg_attrs);
+
+/*
+ * Make physical memory consistent for a set of streaming mode DMA translations
+ * after a transfer.
+ *
+ * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
+ * and usage.
+ */
+static void
+xen_swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
+ int nelems, enum dma_data_direction dir,
+ enum dma_sync_target target)
+{
+ struct scatterlist *sg;
+ int i;
+
+ for_each_sg(sgl, sg, nelems, i)
+ xen_swiotlb_sync_single(hwdev, sg->dma_address,
+ sg_dma_len(sg), dir, target);
+}
+
+void
+xen_swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir)
+{
+ xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_cpu);
+
+void
+xen_swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
+ int nelems, enum dma_data_direction dir)
+{
+ xen_swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_sync_sg_for_device);
+
+int
+xen_swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr)
+{
+ return !dma_addr;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_dma_mapping_error);
+
+/*
+ * Return whether the given device DMA address mask can be supported
+ * properly. For example, if your device can only drive the low 24-bits
+ * during bus mastering, then you would pass 0x00ffffff as the mask to
+ * this function.
+ */
+int
+xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
+{
+ return xen_virt_to_bus(xen_io_tlb_end - 1) <= mask;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_dma_supported);
+
+int
+xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask)
+{
+ if (!dev->dma_mask || !xen_swiotlb_dma_supported(dev, dma_mask))
+ return -EIO;
+
+ *dev->dma_mask = dma_mask;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(xen_swiotlb_set_dma_mask);