Contributors: 26
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Konrad Rzeszutek Wilk |
884 |
49.83% |
5 |
6.67% |
| Christoph Hellwig |
327 |
18.43% |
19 |
25.33% |
| Stefano Stabellini |
319 |
17.98% |
22 |
29.33% |
| Juergen Gross |
38 |
2.14% |
3 |
4.00% |
| Julien Grall |
38 |
2.14% |
2 |
2.67% |
| Jan Beulich |
34 |
1.92% |
1 |
1.33% |
| Ian Campbell |
26 |
1.47% |
1 |
1.33% |
| Joe Jin |
21 |
1.18% |
1 |
1.33% |
| Alexander Duyck |
12 |
0.68% |
3 |
4.00% |
| Zoltan Kiss |
12 |
0.68% |
1 |
1.33% |
| Krzysztof Kozlowski |
12 |
0.68% |
1 |
1.33% |
| Claire Chang |
7 |
0.39% |
2 |
2.67% |
| Joe Perches |
7 |
0.39% |
1 |
1.33% |
| Andrzej Pietrasiewicz |
6 |
0.34% |
1 |
1.33% |
| Souptick Joarder |
5 |
0.28% |
1 |
1.33% |
| Keith Busch |
5 |
0.28% |
1 |
1.33% |
| Arnd Bergmann |
3 |
0.17% |
1 |
1.33% |
| Yinghai Lu |
3 |
0.17% |
1 |
1.33% |
| Paul Gortmaker |
3 |
0.17% |
1 |
1.33% |
| Thomas Gleixner |
2 |
0.11% |
1 |
1.33% |
| Lu Baolu |
2 |
0.11% |
1 |
1.33% |
| Martin Oliveira |
2 |
0.11% |
1 |
1.33% |
| Petr Tesarik |
2 |
0.11% |
1 |
1.33% |
| David L Stevens |
2 |
0.11% |
1 |
1.33% |
| David Vrabel |
1 |
0.06% |
1 |
1.33% |
| Bart Van Assche |
1 |
0.06% |
1 |
1.33% |
| Total |
1774 |
|
75 |
|
// 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, default_swiotlb_limit()) <= 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,
};