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xen/gntdev: Allow mappings for DMA buffers
Allow mappings for DMA backed buffers if grant table module supports such: this extends grant device to not only map buffers made of balloon pages, but also from buffers allocated with dma_alloc_xxx. Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Oleksandr Andrushchenko
Boris Ostrovsky
parent
9bdc7304f5
commit
975ef7ff81
@ -37,6 +37,9 @@
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#include <linux/slab.h>
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#include <linux/highmem.h>
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#include <linux/refcount.h>
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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#include <linux/of_device.h>
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#endif
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#include <xen/xen.h>
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#include <xen/grant_table.h>
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@ -72,6 +75,11 @@ struct gntdev_priv {
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struct mutex lock;
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struct mm_struct *mm;
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struct mmu_notifier mn;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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/* Device for which DMA memory is allocated. */
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struct device *dma_dev;
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#endif
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};
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struct unmap_notify {
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@ -96,10 +104,27 @@ struct grant_map {
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struct gnttab_unmap_grant_ref *kunmap_ops;
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struct page **pages;
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unsigned long pages_vm_start;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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/*
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* If dmabuf_vaddr is not NULL then this mapping is backed by DMA
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* capable memory.
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*/
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struct device *dma_dev;
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/* Flags used to create this DMA buffer: GNTDEV_DMA_FLAG_XXX. */
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int dma_flags;
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void *dma_vaddr;
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dma_addr_t dma_bus_addr;
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/* Needed to avoid allocation in gnttab_dma_free_pages(). */
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xen_pfn_t *frames;
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#endif
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};
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static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
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static struct miscdevice gntdev_miscdev;
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/* ------------------------------------------------------------------ */
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static void gntdev_print_maps(struct gntdev_priv *priv,
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@ -121,8 +146,27 @@ static void gntdev_free_map(struct grant_map *map)
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if (map == NULL)
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return;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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if (map->dma_vaddr) {
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struct gnttab_dma_alloc_args args;
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args.dev = map->dma_dev;
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args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
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args.nr_pages = map->count;
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args.pages = map->pages;
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args.frames = map->frames;
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args.vaddr = map->dma_vaddr;
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args.dev_bus_addr = map->dma_bus_addr;
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gnttab_dma_free_pages(&args);
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} else
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#endif
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if (map->pages)
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gnttab_free_pages(map->count, map->pages);
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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kfree(map->frames);
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#endif
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kfree(map->pages);
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kfree(map->grants);
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kfree(map->map_ops);
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@ -132,7 +176,8 @@ static void gntdev_free_map(struct grant_map *map)
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kfree(map);
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}
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static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
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static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
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int dma_flags)
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{
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struct grant_map *add;
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int i;
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@ -155,6 +200,37 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
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NULL == add->pages)
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goto err;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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add->dma_flags = dma_flags;
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/*
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* Check if this mapping is requested to be backed
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* by a DMA buffer.
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*/
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if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
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struct gnttab_dma_alloc_args args;
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add->frames = kcalloc(count, sizeof(add->frames[0]),
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GFP_KERNEL);
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if (!add->frames)
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goto err;
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/* Remember the device, so we can free DMA memory. */
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add->dma_dev = priv->dma_dev;
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args.dev = priv->dma_dev;
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args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
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args.nr_pages = count;
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args.pages = add->pages;
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args.frames = add->frames;
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if (gnttab_dma_alloc_pages(&args))
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goto err;
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add->dma_vaddr = args.vaddr;
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add->dma_bus_addr = args.dev_bus_addr;
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} else
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#endif
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if (gnttab_alloc_pages(count, add->pages))
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goto err;
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@ -325,6 +401,14 @@ static int map_grant_pages(struct grant_map *map)
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map->unmap_ops[i].handle = map->map_ops[i].handle;
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if (use_ptemod)
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map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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else if (map->dma_vaddr) {
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unsigned long bfn;
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bfn = pfn_to_bfn(page_to_pfn(map->pages[i]));
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map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn);
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}
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#endif
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}
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return err;
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}
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@ -548,6 +632,17 @@ static int gntdev_open(struct inode *inode, struct file *flip)
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}
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flip->private_data = priv;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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priv->dma_dev = gntdev_miscdev.this_device;
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/*
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* The device is not spawn from a device tree, so arch_setup_dma_ops
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* is not called, thus leaving the device with dummy DMA ops.
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* Fix this by calling of_dma_configure() with a NULL node to set
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* default DMA ops.
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*/
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of_dma_configure(priv->dma_dev, NULL, true);
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#endif
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pr_debug("priv %p\n", priv);
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return 0;
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@ -589,7 +684,7 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
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return -EINVAL;
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err = -ENOMEM;
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map = gntdev_alloc_map(priv, op.count);
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map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
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if (!map)
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return err;
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@ -200,4 +200,19 @@ struct ioctl_gntdev_grant_copy {
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/* Send an interrupt on the indicated event channel */
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#define UNMAP_NOTIFY_SEND_EVENT 0x2
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/*
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* Flags to be used while requesting memory mapping's backing storage
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* to be allocated with DMA API.
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*/
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/*
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* The buffer is backed with memory allocated with dma_alloc_wc.
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*/
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#define GNTDEV_DMA_FLAG_WC (1 << 0)
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/*
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* The buffer is backed with memory allocated with dma_alloc_coherent.
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*/
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#define GNTDEV_DMA_FLAG_COHERENT (1 << 1)
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#endif /* __LINUX_PUBLIC_GNTDEV_H__ */
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