Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 409 insertions, 0 deletions

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
new file mode 100644
index 000000000..7290f2b40
--- /dev/null
+++ b/drivers/xen/swiotlb-xen.c
@@ -0,0 +1,409 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Copyright 2010
+ *  by Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+ *
+ * This code provides a IOMMU for Xen PV guests with PCI passthrough.
+ *
+ * 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/memblock.h>
+#include <linux/dma-direct.h>
+#include <linux/dma-map-ops.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 <trace/events/swiotlb.h>
+#define MAX_DMA_BITS 32
+
+/*
+ * Quick lookup value of the bus address of the IOTLB.
+ */
+
+static inline phys_addr_t xen_phys_to_bus(struct device *dev, phys_addr_t paddr)
+{
+	unsigned long bfn = pfn_to_bfn(XEN_PFN_DOWN(paddr));
+	phys_addr_t baddr = (phys_addr_t)bfn << XEN_PAGE_SHIFT;
+
+	baddr |= paddr & ~XEN_PAGE_MASK;
+	return baddr;
+}
+
+static inline dma_addr_t xen_phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	return phys_to_dma(dev, xen_phys_to_bus(dev, paddr));
+}
+
+static inline phys_addr_t xen_bus_to_phys(struct device *dev,
+					  phys_addr_t baddr)
+{
+	unsigned long xen_pfn = bfn_to_pfn(XEN_PFN_DOWN(baddr));
+	phys_addr_t paddr = (xen_pfn << XEN_PAGE_SHIFT) |
+			    (baddr & ~XEN_PAGE_MASK);
+
+	return paddr;
+}
+
+static inline phys_addr_t xen_dma_to_phys(struct device *dev,
+					  dma_addr_t dma_addr)
+{
+	return xen_bus_to_phys(dev, dma_to_phys(dev, dma_addr));
+}
+
+static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
+{
+	unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
+	unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
+
+	next_bfn = pfn_to_bfn(xen_pfn);
+
+	for (i = 1; i < nr_pages; i++)
+		if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
+			return 1;
+
+	return 0;
+}
+
+static int is_xen_swiotlb_buffer(struct device *dev, dma_addr_t dma_addr)
+{
+	unsigned long bfn = XEN_PFN_DOWN(dma_to_phys(dev, dma_addr));
+	unsigned long xen_pfn = bfn_to_local_pfn(bfn);
+	phys_addr_t paddr = (phys_addr_t)xen_pfn << XEN_PAGE_SHIFT;
+
+	/* 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_DOWN(paddr)))
+		return is_swiotlb_buffer(dev, paddr);
+	return 0;
+}
+
+#ifdef CONFIG_X86
+int xen_swiotlb_fixup(void *buf, unsigned long nslabs)
+{
+	int rc;
+	unsigned int order = get_order(IO_TLB_SEGSIZE << IO_TLB_SHIFT);
+	unsigned int i, dma_bits = order + PAGE_SHIFT;
+	dma_addr_t dma_handle;
+	phys_addr_t p = virt_to_phys(buf);
+
+	BUILD_BUG_ON(IO_TLB_SEGSIZE & (IO_TLB_SEGSIZE - 1));
+	BUG_ON(nslabs % IO_TLB_SEGSIZE);
+
+	i = 0;
+	do {
+		do {
+			rc = xen_create_contiguous_region(
+				p + (i << IO_TLB_SHIFT), order,
+				dma_bits, &dma_handle);
+		} while (rc && dma_bits++ < MAX_DMA_BITS);
+		if (rc)
+			return rc;
+
+		i += IO_TLB_SEGSIZE;
+	} while (i < nslabs);
+	return 0;
+}
+
+static void *
+xen_swiotlb_alloc_coherent(struct device *dev, size_t size,
+		dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
+{
+	u64 dma_mask = dev->coherent_dma_mask;
+	int order = get_order(size);
+	phys_addr_t phys;
+	void *ret;
+
+	/* Align the allocation to the Xen page size */
+	size = 1UL << (order + XEN_PAGE_SHIFT);
+
+	ret = (void *)__get_free_pages(flags, get_order(size));
+	if (!ret)
+		return ret;
+	phys = virt_to_phys(ret);
+
+	*dma_handle = xen_phys_to_dma(dev, phys);
+	if (*dma_handle + size - 1 > dma_mask ||
+	    range_straddles_page_boundary(phys, size)) {
+		if (xen_create_contiguous_region(phys, order, fls64(dma_mask),
+				dma_handle) != 0)
+			goto out_free_pages;
+		SetPageXenRemapped(virt_to_page(ret));
+	}
+
+	memset(ret, 0, size);
+	return ret;
+
+out_free_pages:
+	free_pages((unsigned long)ret, get_order(size));
+	return NULL;
+}
+
+static void
+xen_swiotlb_free_coherent(struct device *dev, size_t size, void *vaddr,
+		dma_addr_t dma_handle, unsigned long attrs)
+{
+	phys_addr_t phys = virt_to_phys(vaddr);
+	int order = get_order(size);
+
+	/* Convert the size to actually allocated. */
+	size = 1UL << (order + XEN_PAGE_SHIFT);
+
+	if (WARN_ON_ONCE(dma_handle + size - 1 > dev->coherent_dma_mask) ||
+	    WARN_ON_ONCE(range_straddles_page_boundary(phys, size)))
+	    	return;
+
+	if (TestClearPageXenRemapped(virt_to_page(vaddr)))
+		xen_destroy_contiguous_region(phys, order);
+	free_pages((unsigned long)vaddr, get_order(size));
+}
+#endif /* CONFIG_X86 */
+
+/*
+ * 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.
+ */
+static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
+				unsigned long offset, size_t size,
+				enum dma_data_direction dir,
+				unsigned long attrs)
+{
+	phys_addr_t map, phys = page_to_phys(page) + offset;
+	dma_addr_t dev_addr = xen_phys_to_dma(dev, 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, true) &&
+	    !range_straddles_page_boundary(phys, size) &&
+		!xen_arch_need_swiotlb(dev, phys, dev_addr) &&
+		!is_swiotlb_force_bounce(dev))
+		goto done;
+
+	/*
+	 * Oh well, have to allocate and map a bounce buffer.
+	 */
+	trace_swiotlb_bounced(dev, dev_addr, size);
+
+	map = swiotlb_tbl_map_single(dev, phys, size, size, 0, dir, attrs);
+	if (map == (phys_addr_t)DMA_MAPPING_ERROR)
+		return DMA_MAPPING_ERROR;
+
+	phys = map;
+	dev_addr = xen_phys_to_dma(dev, map);
+
+	/*
+	 * Ensure that the address returned is DMA'ble
+	 */
+	if (unlikely(!dma_capable(dev, dev_addr, size, true))) {
+		swiotlb_tbl_unmap_single(dev, map, size, dir,
+				attrs | DMA_ATTR_SKIP_CPU_SYNC);
+		return DMA_MAPPING_ERROR;
+	}
+
+done:
+	if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+		if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dev_addr))))
+			arch_sync_dma_for_device(phys, size, dir);
+		else
+			xen_dma_sync_for_device(dev, dev_addr, size, dir);
+	}
+	return dev_addr;
+}
+
+/*
+ * 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_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
+		size_t size, enum dma_data_direction dir, unsigned long attrs)
+{
+	phys_addr_t paddr = xen_dma_to_phys(hwdev, dev_addr);
+
+	BUG_ON(dir == DMA_NONE);
+
+	if (!dev_is_dma_coherent(hwdev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+		if (pfn_valid(PFN_DOWN(dma_to_phys(hwdev, dev_addr))))
+			arch_sync_dma_for_cpu(paddr, size, dir);
+		else
+			xen_dma_sync_for_cpu(hwdev, dev_addr, size, dir);
+	}
+
+	/* NOTE: We use dev_addr here, not paddr! */
+	if (is_xen_swiotlb_buffer(hwdev, dev_addr))
+		swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
+}
+
+static void
+xen_swiotlb_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr,
+		size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
+
+	if (!dev_is_dma_coherent(dev)) {
+		if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
+			arch_sync_dma_for_cpu(paddr, size, dir);
+		else
+			xen_dma_sync_for_cpu(dev, dma_addr, size, dir);
+	}
+
+	if (is_xen_swiotlb_buffer(dev, dma_addr))
+		swiotlb_sync_single_for_cpu(dev, paddr, size, dir);
+}
+
+static void
+xen_swiotlb_sync_single_for_device(struct device *dev, dma_addr_t dma_addr,
+		size_t size, enum dma_data_direction dir)
+{
+	phys_addr_t paddr = xen_dma_to_phys(dev, dma_addr);
+
+	if (is_xen_swiotlb_buffer(dev, dma_addr))
+		swiotlb_sync_single_for_device(dev, paddr, size, dir);
+
+	if (!dev_is_dma_coherent(dev)) {
+		if (pfn_valid(PFN_DOWN(dma_to_phys(dev, dma_addr))))
+			arch_sync_dma_for_device(paddr, size, dir);
+		else
+			xen_dma_sync_for_device(dev, dma_addr, size, dir);
+	}
+}
+
+/*
+ * Unmap a set of streaming mode DMA translations.  Again, cpu read rules
+ * concerning calls here are the same as for swiotlb_unmap_page() above.
+ */
+static void
+xen_swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	struct scatterlist *sg;
+	int i;
+
+	BUG_ON(dir == DMA_NONE);
+
+	for_each_sg(sgl, sg, nelems, i)
+		xen_swiotlb_unmap_page(hwdev, sg->dma_address, sg_dma_len(sg),
+				dir, attrs);
+
+}
+
+static int
+xen_swiotlb_map_sg(struct device *dev, struct scatterlist *sgl, int nelems,
+		enum dma_data_direction dir, unsigned long attrs)
+{
+	struct scatterlist *sg;
+	int i;
+
+	BUG_ON(dir == DMA_NONE);
+
+	for_each_sg(sgl, sg, nelems, i) {
+		sg->dma_address = xen_swiotlb_map_page(dev, sg_page(sg),
+				sg->offset, sg->length, dir, attrs);
+		if (sg->dma_address == DMA_MAPPING_ERROR)
+			goto out_unmap;
+		sg_dma_len(sg) = sg->length;
+	}
+
+	return nelems;
+out_unmap:
+	xen_swiotlb_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
+	sg_dma_len(sgl) = 0;
+	return -EIO;
+}
+
+static void
+xen_swiotlb_sync_sg_for_cpu(struct device *dev, struct scatterlist *sgl,
+			    int nelems, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nelems, i) {
+		xen_swiotlb_sync_single_for_cpu(dev, sg->dma_address,
+				sg->length, dir);
+	}
+}
+
+static void
+xen_swiotlb_sync_sg_for_device(struct device *dev, struct scatterlist *sgl,
+			       int nelems, enum dma_data_direction dir)
+{
+	struct scatterlist *sg;
+	int i;
+
+	for_each_sg(sgl, sg, nelems, i) {
+		xen_swiotlb_sync_single_for_device(dev, sg->dma_address,
+				sg->length, dir);
+	}
+}
+
+/*
+ * 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.
+ */
+static int
+xen_swiotlb_dma_supported(struct device *hwdev, u64 mask)
+{
+	return xen_phys_to_dma(hwdev, io_tlb_default_mem.end - 1) <= mask;
+}
+
+const struct dma_map_ops xen_swiotlb_dma_ops = {
+#ifdef CONFIG_X86
+	.alloc = xen_swiotlb_alloc_coherent,
+	.free = xen_swiotlb_free_coherent,
+#else
+	.alloc = dma_direct_alloc,
+	.free = dma_direct_free,
+#endif
+	.sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
+	.sync_single_for_device = xen_swiotlb_sync_single_for_device,
+	.sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
+	.sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
+	.map_sg = xen_swiotlb_map_sg,
+	.unmap_sg = xen_swiotlb_unmap_sg,
+	.map_page = xen_swiotlb_map_page,
+	.unmap_page = xen_swiotlb_unmap_page,
+	.dma_supported = xen_swiotlb_dma_supported,
+	.mmap = dma_common_mmap,
+	.get_sgtable = dma_common_get_sgtable,
+	.alloc_pages = dma_common_alloc_pages,
+	.free_pages = dma_common_free_pages,
+	.max_mapping_size = swiotlb_max_mapping_size,
+};