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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#undef DEBUG
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#include <linux/dma-mapping.h>#include <linux/module.h>#include <linux/kernel.h>#include <linux/init.h>#include <linux/miscdevice.h>#include <linux/fs.h>#include <linux/uaccess.h>#include <linux/sched.h>#include <linux/sched/mm.h>#include <linux/spinlock.h>#include <linux/slab.h>#include <linux/highmem.h>#include <linux/refcount.h>#include <linux/workqueue.h>
#include <xen/xen.h>#include <xen/grant_table.h>#include <xen/balloon.h>#include <xen/gntdev.h>#include <xen/events.h>#include <xen/page.h>#include <asm/xen/hypervisor.h>#include <asm/xen/hypercall.h>
#include "gntdev-common.h"#ifdef CONFIG_XEN_GNTDEV_DMABUF#include "gntdev-dmabuf.h"#endif
MODULE_LICENSE("GPL");MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, " "Gerd Hoffmann <kraxel@redhat.com>");MODULE_DESCRIPTION("User-space granted page access driver");
#define GNTDEV_COPY_BATCH 16
struct gntdev_copy_batch { struct gnttab_copy ops[GNTDEV_COPY_BATCH]; struct page *pages[GNTDEV_COPY_BATCH]; s16 __user *status[GNTDEV_COPY_BATCH]; unsigned int nr_ops; unsigned int nr_pages; bool writeable; struct gntdev_copy_batch *next;};
static unsigned int limit = 64*1024;module_param(limit, uint, 0644);MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by one mapping request");
static void unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages);
static struct miscdevice gntdev_miscdev;
/* ------------------------------------------------------------------ */
bool gntdev_test_page_count(unsigned int count){ return !count || count > limit;}
static void gntdev_print_maps(struct gntdev_priv *priv, char *text, int text_index){#ifdef DEBUG struct gntdev_grant_map *map;
pr_debug("%s: maps list (priv %p)\n", __func__, priv); list_for_each_entry(map, &priv->maps, next) pr_debug(" index %2d, count %2d %s\n", map->index, map->count, map->index == text_index && text ? text : "");#endif}
static void gntdev_free_map(struct gntdev_grant_map *map){ if (map == NULL) return;
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC if (map->dma_vaddr) { struct gnttab_dma_alloc_args args;
args.dev = map->dma_dev; args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT); args.nr_pages = map->count; args.pages = map->pages; args.frames = map->frames; args.vaddr = map->dma_vaddr; args.dev_bus_addr = map->dma_bus_addr;
gnttab_dma_free_pages(&args); } else#endif if (map->pages) gnttab_free_pages(map->count, map->pages);
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC kvfree(map->frames);#endif kvfree(map->pages); kvfree(map->grants); kvfree(map->map_ops); kvfree(map->unmap_ops); kvfree(map->kmap_ops); kvfree(map->kunmap_ops); kvfree(map->being_removed); kfree(map);}
struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count, int dma_flags){ struct gntdev_grant_map *add; int i;
add = kzalloc_obj(*add); if (NULL == add) return NULL;
add->grants = kvmalloc_objs(add->grants[0], count); add->map_ops = kvmalloc_objs(add->map_ops[0], count); add->unmap_ops = kvmalloc_objs(add->unmap_ops[0], count); add->pages = kvzalloc_objs(add->pages[0], count); add->being_removed = kvzalloc_objs(add->being_removed[0], count); if (NULL == add->grants || NULL == add->map_ops || NULL == add->unmap_ops || NULL == add->pages || NULL == add->being_removed) goto err; if (xen_pv_domain()) { add->kmap_ops = kvmalloc_objs(add->kmap_ops[0], count); add->kunmap_ops = kvmalloc_objs(add->kunmap_ops[0], count); if (NULL == add->kmap_ops || NULL == add->kunmap_ops) goto err; }
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC add->dma_flags = dma_flags;
/* * Check if this mapping is requested to be backed * by a DMA buffer. */ if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) { struct gnttab_dma_alloc_args args;
add->frames = kvzalloc_objs(add->frames[0], count); if (!add->frames) goto err;
/* Remember the device, so we can free DMA memory. */ add->dma_dev = priv->dma_dev;
args.dev = priv->dma_dev; args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT); args.nr_pages = count; args.pages = add->pages; args.frames = add->frames;
if (gnttab_dma_alloc_pages(&args)) goto err;
add->dma_vaddr = args.vaddr; add->dma_bus_addr = args.dev_bus_addr; } else#endif if (gnttab_alloc_pages(count, add->pages)) goto err;
for (i = 0; i < count; i++) { add->grants[i].domid = DOMID_INVALID; add->grants[i].ref = INVALID_GRANT_REF; add->map_ops[i].handle = INVALID_GRANT_HANDLE; add->unmap_ops[i].handle = INVALID_GRANT_HANDLE; if (xen_pv_domain()) { add->kmap_ops[i].handle = INVALID_GRANT_HANDLE; add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE; } }
add->index = 0; add->count = count; refcount_set(&add->users, 1);
return add;
err: gntdev_free_map(add); return NULL;}
void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add){ struct gntdev_grant_map *map;
list_for_each_entry(map, &priv->maps, next) { if (add->index + add->count < map->index) { list_add_tail(&add->next, &map->next); goto done; } add->index = map->index + map->count; } list_add_tail(&add->next, &priv->maps);
done: gntdev_print_maps(priv, "[new]", add->index);}
static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv, int index, int count){ struct gntdev_grant_map *map;
list_for_each_entry(map, &priv->maps, next) { if (map->index != index) continue; if (count && map->count != count) continue; return map; } return NULL;}
void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map){ if (!map) return;
if (!refcount_dec_and_test(&map->users)) return;
if (map->pages && !xen_pv_domain()) { /* * Increment the reference count. This ensures that the * subsequent call to unmap_grant_pages() will not wind up * re-entering itself. It *can* wind up calling * gntdev_put_map() recursively, but such calls will be with a * reference count greater than 1, so they will return before * this code is reached. The recursion depth is thus limited to * 1. Do NOT use refcount_inc() here, as it will detect that * the reference count is zero and WARN(). */ refcount_set(&map->users, 1);
/* * Unmap the grants. This may or may not be asynchronous, so it * is possible that the reference count is 1 on return, but it * could also be greater than 1. */ unmap_grant_pages(map, 0, map->count);
/* Check if the memory now needs to be freed */ if (!refcount_dec_and_test(&map->users)) return;
/* * All pages have been returned to the hypervisor, so free the * map. */ }
if (xen_pv_domain() && map->notifier_init) mmu_interval_notifier_remove(&map->notifier);
if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) { notify_remote_via_evtchn(map->notify.event); evtchn_put(map->notify.event); } gntdev_free_map(map);}
/* ------------------------------------------------------------------ */
static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data){ struct gntdev_grant_map *map = data; unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT; int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte | (1 << _GNTMAP_guest_avail0); u64 pte_maddr;
BUG_ON(pgnr >= map->count); pte_maddr = arbitrary_virt_to_machine(pte).maddr;
/* Note: this will perform a pte_mkspecial() through the hypercall. */ gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags, map->grants[pgnr].ref, map->grants[pgnr].domid); gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags, INVALID_GRANT_HANDLE); return 0;}
int gntdev_map_grant_pages(struct gntdev_grant_map *map){ size_t alloced = 0; int i, err = 0;
if (!xen_pv_domain()) { /* Note: it could already be mapped */ if (map->map_ops[0].handle != INVALID_GRANT_HANDLE) return 0; for (i = 0; i < map->count; i++) { unsigned long addr = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); gnttab_set_map_op(&map->map_ops[i], addr, map->flags, map->grants[i].ref, map->grants[i].domid); gnttab_set_unmap_op(&map->unmap_ops[i], addr, map->flags, INVALID_GRANT_HANDLE); } } else { /* * Setup the map_ops corresponding to the pte entries pointing * to the kernel linear addresses of the struct pages. * These ptes are completely different from the user ptes dealt * with find_grant_ptes. * Note that GNTMAP_device_map isn't needed here: The * dev_bus_addr output field gets consumed only from ->map_ops, * and by not requesting it when mapping we also avoid needing * to mirror dev_bus_addr into ->unmap_ops (and holding an extra * reference to the page in the hypervisor). */ unsigned int flags = (map->flags & ~GNTMAP_device_map) | GNTMAP_host_map;
for (i = 0; i < map->count; i++) { unsigned long address = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); BUG_ON(PageHighMem(map->pages[i]));
gnttab_set_map_op(&map->kmap_ops[i], address, flags, map->grants[i].ref, map->grants[i].domid); gnttab_set_unmap_op(&map->kunmap_ops[i], address, flags, INVALID_GRANT_HANDLE); } }
pr_debug("map %d+%d\n", map->index, map->count); err = gnttab_map_refs(map->map_ops, map->kmap_ops, map->pages, map->count);
for (i = 0; i < map->count; i++) { if (map->map_ops[i].status == GNTST_okay) { map->unmap_ops[i].handle = map->map_ops[i].handle; alloced++; } else if (!err) err = -EINVAL;
if (map->flags & GNTMAP_device_map) map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
if (xen_pv_domain()) { if (map->kmap_ops[i].status == GNTST_okay) { alloced++; map->kunmap_ops[i].handle = map->kmap_ops[i].handle; } else if (!err) err = -EINVAL; } } atomic_add(alloced, &map->live_grants); return err;}
static void __unmap_grant_pages_done(int result, struct gntab_unmap_queue_data *data){ unsigned int i; struct gntdev_grant_map *map = data->data; unsigned int offset = data->unmap_ops - map->unmap_ops; int successful_unmaps = 0; int live_grants;
for (i = 0; i < data->count; i++) { if (map->unmap_ops[offset + i].status == GNTST_okay && map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) successful_unmaps++;
WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay && map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("unmap handle=%d st=%d\n", map->unmap_ops[offset+i].handle, map->unmap_ops[offset+i].status); map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; if (xen_pv_domain()) { if (map->kunmap_ops[offset + i].status == GNTST_okay && map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE) successful_unmaps++;
WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay && map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE); pr_debug("kunmap handle=%u st=%d\n", map->kunmap_ops[offset+i].handle, map->kunmap_ops[offset+i].status); map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE; } }
/* * Decrease the live-grant counter. This must happen after the loop to * prevent premature reuse of the grants by gnttab_mmap(). */ live_grants = atomic_sub_return(successful_unmaps, &map->live_grants); if (WARN_ON(live_grants < 0)) pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n", __func__, live_grants, successful_unmaps);
/* Release reference taken by __unmap_grant_pages */ gntdev_put_map(NULL, map);}
static void __unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages){ if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) { int pgno = (map->notify.addr >> PAGE_SHIFT);
if (pgno >= offset && pgno < offset + pages) { /* No need for kmap, pages are in lowmem */ uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0; map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE; } }
map->unmap_data.unmap_ops = map->unmap_ops + offset; map->unmap_data.kunmap_ops = xen_pv_domain() ? map->kunmap_ops + offset : NULL; map->unmap_data.pages = map->pages + offset; map->unmap_data.count = pages; map->unmap_data.done = __unmap_grant_pages_done; map->unmap_data.data = map; refcount_inc(&map->users); /* to keep map alive during async call below */
gnttab_unmap_refs_async(&map->unmap_data);}
static void unmap_grant_pages(struct gntdev_grant_map *map, int offset, int pages){ int range;
if (atomic_read(&map->live_grants) == 0) return; /* Nothing to do */
pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
/* It is possible the requested range will have a "hole" where we * already unmapped some of the grants. Only unmap valid ranges. */ while (pages) { while (pages && map->being_removed[offset]) { offset++; pages--; } range = 0; while (range < pages) { if (map->being_removed[offset + range]) break; map->being_removed[offset + range] = true; range++; } if (range) __unmap_grant_pages(map, offset, range); offset += range; pages -= range; }}
/* ------------------------------------------------------------------ */
static void gntdev_vma_open(struct vm_area_struct *vma){ struct gntdev_grant_map *map = vma->vm_private_data;
pr_debug("gntdev_vma_open %p\n", vma); refcount_inc(&map->users);}
static void gntdev_vma_close(struct vm_area_struct *vma){ struct gntdev_grant_map *map = vma->vm_private_data; struct file *file = vma->vm_file; struct gntdev_priv *priv = file->private_data;
pr_debug("gntdev_vma_close %p\n", vma);
vma->vm_private_data = NULL; gntdev_put_map(priv, map);}
static struct page *gntdev_vma_find_normal_page(struct vm_area_struct *vma, unsigned long addr){ struct gntdev_grant_map *map = vma->vm_private_data;
return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];}
static const struct vm_operations_struct gntdev_vmops = { .open = gntdev_vma_open, .close = gntdev_vma_close, .find_normal_page = gntdev_vma_find_normal_page,};
/* ------------------------------------------------------------------ */
static bool gntdev_invalidate(struct mmu_interval_notifier *mn, const struct mmu_notifier_range *range, unsigned long cur_seq){ struct gntdev_grant_map *map = container_of(mn, struct gntdev_grant_map, notifier); unsigned long mstart, mend; unsigned long map_start, map_end;
if (!mmu_notifier_range_blockable(range)) return false;
map_start = map->pages_vm_start; map_end = map->pages_vm_start + (map->count << PAGE_SHIFT);
/* * If the VMA is split or otherwise changed the notifier is not * updated, but we don't want to process VA's outside the modified * VMA. FIXME: It would be much more understandable to just prevent * modifying the VMA in the first place. */ if (map_start >= range->end || map_end <= range->start) return true;
mstart = max(range->start, map_start); mend = min(range->end, map_end); pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n", map->index, map->count, map_start, map_end, range->start, range->end, mstart, mend); unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT, (mend - mstart) >> PAGE_SHIFT);
return true;}
static const struct mmu_interval_notifier_ops gntdev_mmu_ops = { .invalidate = gntdev_invalidate,};
/* ------------------------------------------------------------------ */
static int gntdev_open(struct inode *inode, struct file *flip){ struct gntdev_priv *priv;
priv = kzalloc_obj(*priv); if (!priv) return -ENOMEM;
INIT_LIST_HEAD(&priv->maps); mutex_init(&priv->lock);
mutex_init(&priv->batch_lock);
#ifdef CONFIG_XEN_GNTDEV_DMABUF priv->dmabuf_priv = gntdev_dmabuf_init(flip); if (IS_ERR(priv->dmabuf_priv)) { int ret = PTR_ERR(priv->dmabuf_priv);
kfree(priv); return ret; }#endif
flip->private_data = priv;#ifdef CONFIG_XEN_GRANT_DMA_ALLOC priv->dma_dev = gntdev_miscdev.this_device; dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));#endif pr_debug("priv %p\n", priv);
return 0;}
static int gntdev_release(struct inode *inode, struct file *flip){ struct gntdev_priv *priv = flip->private_data; struct gntdev_grant_map *map; struct gntdev_copy_batch *batch;
pr_debug("priv %p\n", priv);
mutex_lock(&priv->lock); while (!list_empty(&priv->maps)) { map = list_entry(priv->maps.next, struct gntdev_grant_map, next); list_del(&map->next); gntdev_put_map(NULL /* already removed */, map); } mutex_unlock(&priv->lock);
mutex_lock(&priv->batch_lock); while (priv->batch) { batch = priv->batch; priv->batch = batch->next; kfree(batch); } mutex_unlock(&priv->batch_lock);
#ifdef CONFIG_XEN_GNTDEV_DMABUF gntdev_dmabuf_fini(priv->dmabuf_priv);#endif
kfree(priv); return 0;}
static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv, struct ioctl_gntdev_map_grant_ref __user *u){ struct ioctl_gntdev_map_grant_ref op; struct gntdev_grant_map *map; int err;
if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, add %d\n", priv, op.count); if (unlikely(gntdev_test_page_count(op.count))) return -EINVAL;
err = -ENOMEM; map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */); if (!map) return err;
if (copy_from_user(map->grants, &u->refs, sizeof(map->grants[0]) * op.count) != 0) { gntdev_put_map(NULL, map); return -EFAULT; }
mutex_lock(&priv->lock); gntdev_add_map(priv, map); op.index = map->index << PAGE_SHIFT;
if (copy_to_user(u, &op, sizeof(op)) != 0) { list_del(&map->next); mutex_unlock(&priv->lock); gntdev_put_map(priv, map); return -EFAULT; }
mutex_unlock(&priv->lock); return 0;}
static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv, struct ioctl_gntdev_unmap_grant_ref __user *u){ struct ioctl_gntdev_unmap_grant_ref op; struct gntdev_grant_map *map; int err = -ENOENT;
if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count); if (map) { list_del(&map->next); err = 0; } mutex_unlock(&priv->lock); if (map) gntdev_put_map(priv, map); return err;}
static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, struct ioctl_gntdev_get_offset_for_vaddr __user *u){ struct ioctl_gntdev_get_offset_for_vaddr op; struct vm_area_struct *vma; struct gntdev_grant_map *map; int rv = -EINVAL;
if (copy_from_user(&op, u, sizeof(op)) != 0) return -EFAULT; pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
mmap_read_lock(current->mm); vma = find_vma(current->mm, op.vaddr); if (!vma || vma->vm_ops != &gntdev_vmops) goto out_unlock;
map = vma->vm_private_data; if (!map) goto out_unlock;
op.offset = map->index << PAGE_SHIFT; op.count = map->count; rv = 0;
out_unlock: mmap_read_unlock(current->mm);
if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) return -EFAULT; return rv;}
static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u){ struct ioctl_gntdev_unmap_notify op; struct gntdev_grant_map *map; int rc; int out_flags; evtchn_port_t out_event;
if (copy_from_user(&op, u, sizeof(op))) return -EFAULT;
if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) return -EINVAL;
/* We need to grab a reference to the event channel we are going to use * to send the notify before releasing the reference we may already have * (if someone has called this ioctl twice). This is required so that * it is possible to change the clear_byte part of the notification * without disturbing the event channel part, which may now be the last * reference to that event channel. */ if (op.action & UNMAP_NOTIFY_SEND_EVENT) { if (evtchn_get(op.event_channel_port)) return -EINVAL; }
out_flags = op.action; out_event = op.event_channel_port;
mutex_lock(&priv->lock);
list_for_each_entry(map, &priv->maps, next) { uint64_t begin = map->index << PAGE_SHIFT; uint64_t end = (map->index + map->count) << PAGE_SHIFT; if (op.index >= begin && op.index < end) goto found; } rc = -ENOENT; goto unlock_out;
found: if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) && (map->flags & GNTMAP_readonly)) { rc = -EINVAL; goto unlock_out; }
out_flags = map->notify.flags; out_event = map->notify.event;
map->notify.flags = op.action; map->notify.addr = op.index - (map->index << PAGE_SHIFT); map->notify.event = op.event_channel_port;
rc = 0;
unlock_out: mutex_unlock(&priv->lock);
/* Drop the reference to the event channel we did not save in the map */ if (out_flags & UNMAP_NOTIFY_SEND_EVENT) evtchn_put(out_event);
return rc;}
static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, unsigned long *gfn){ unsigned long addr = (unsigned long)virt; struct page *page; unsigned long xen_pfn; int ret;
ret = pin_user_pages_fast(addr, 1, batch->writeable ? FOLL_WRITE : 0, &page); if (ret < 0) return ret;
batch->pages[batch->nr_pages++] = page;
xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK); *gfn = pfn_to_gfn(xen_pfn);
return 0;}
static void gntdev_put_pages(struct gntdev_copy_batch *batch){ unpin_user_pages_dirty_lock(batch->pages, batch->nr_pages, batch->writeable); batch->nr_pages = 0; batch->writeable = false;}
static int gntdev_copy(struct gntdev_copy_batch *batch){ unsigned int i;
gnttab_batch_copy(batch->ops, batch->nr_ops); gntdev_put_pages(batch);
/* * For each completed op, update the status if the op failed * and all previous ops for the segment were successful. */ for (i = 0; i < batch->nr_ops; i++) { s16 status = batch->ops[i].status; s16 old_status;
if (status == GNTST_okay) continue;
if (get_user(old_status, batch->status[i])) return -EFAULT;
if (old_status != GNTST_okay) continue;
if (put_user(status, batch->status[i])) return -EFAULT; }
batch->nr_ops = 0; return 0;}
static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch, struct gntdev_grant_copy_segment *seg, s16 __user *status){ uint16_t copied = 0;
/* * Disallow local -> local copies since there is only space in * batch->pages for one page per-op and this would be a very * expensive memcpy(). */ if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref))) return -EINVAL;
/* Can't cross page if source/dest is a grant ref. */ if (seg->flags & GNTCOPY_source_gref) { if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE) return -EINVAL; } if (seg->flags & GNTCOPY_dest_gref) { if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE) return -EINVAL; }
if (put_user(GNTST_okay, status)) return -EFAULT;
while (copied < seg->len) { struct gnttab_copy *op; void __user *virt; size_t len, off; unsigned long gfn; int ret;
if (batch->nr_ops >= GNTDEV_COPY_BATCH) { ret = gntdev_copy(batch); if (ret < 0) return ret; }
len = seg->len - copied;
op = &batch->ops[batch->nr_ops]; op->flags = 0;
if (seg->flags & GNTCOPY_source_gref) { op->source.u.ref = seg->source.foreign.ref; op->source.domid = seg->source.foreign.domid; op->source.offset = seg->source.foreign.offset + copied; op->flags |= GNTCOPY_source_gref; } else { virt = seg->source.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); batch->writeable = false;
ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret;
op->source.u.gmfn = gfn; op->source.domid = DOMID_SELF; op->source.offset = off; }
if (seg->flags & GNTCOPY_dest_gref) { op->dest.u.ref = seg->dest.foreign.ref; op->dest.domid = seg->dest.foreign.domid; op->dest.offset = seg->dest.foreign.offset + copied; op->flags |= GNTCOPY_dest_gref; } else { virt = seg->dest.virt + copied; off = (unsigned long)virt & ~XEN_PAGE_MASK; len = min(len, (size_t)XEN_PAGE_SIZE - off); batch->writeable = true;
ret = gntdev_get_page(batch, virt, &gfn); if (ret < 0) return ret;
op->dest.u.gmfn = gfn; op->dest.domid = DOMID_SELF; op->dest.offset = off; }
op->len = len; copied += len;
batch->status[batch->nr_ops] = status; batch->nr_ops++; }
return 0;}
static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u){ struct ioctl_gntdev_grant_copy copy; struct gntdev_copy_batch *batch; unsigned int i; int ret = 0;
if (copy_from_user(©, u, sizeof(copy))) return -EFAULT;
mutex_lock(&priv->batch_lock); if (!priv->batch) { batch = kmalloc_obj(*batch); } else { batch = priv->batch; priv->batch = batch->next; } mutex_unlock(&priv->batch_lock); if (!batch) return -ENOMEM;
batch->nr_ops = 0; batch->nr_pages = 0;
for (i = 0; i < copy.count; i++) { struct gntdev_grant_copy_segment seg;
if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) { ret = -EFAULT; gntdev_put_pages(batch); goto out; }
ret = gntdev_grant_copy_seg(batch, &seg, ©.segments[i].status); if (ret < 0) { gntdev_put_pages(batch); goto out; }
cond_resched(); } if (batch->nr_ops) ret = gntdev_copy(batch);
out: mutex_lock(&priv->batch_lock); batch->next = priv->batch; priv->batch = batch; mutex_unlock(&priv->batch_lock);
return ret;}
static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg){ struct gntdev_priv *priv = flip->private_data; void __user *ptr = (void __user *)arg;
switch (cmd) { case IOCTL_GNTDEV_MAP_GRANT_REF: return gntdev_ioctl_map_grant_ref(priv, ptr);
case IOCTL_GNTDEV_UNMAP_GRANT_REF: return gntdev_ioctl_unmap_grant_ref(priv, ptr);
case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR: return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: return gntdev_ioctl_notify(priv, ptr);
case IOCTL_GNTDEV_GRANT_COPY: return gntdev_ioctl_grant_copy(priv, ptr);
#ifdef CONFIG_XEN_GNTDEV_DMABUF case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS: return gntdev_ioctl_dmabuf_exp_from_refs(priv, ptr);
case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED: return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS: return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
case IOCTL_GNTDEV_DMABUF_IMP_RELEASE: return gntdev_ioctl_dmabuf_imp_release(priv, ptr);#endif
default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; }
return 0;}
static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma){ struct gntdev_priv *priv = flip->private_data; int index = vma->vm_pgoff; int count = vma_pages(vma); struct gntdev_grant_map *map; int err = -EINVAL;
if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED)) return -EINVAL;
/* * Private mappings of foreign grant pages must never become * writable: they would take the COW path on granted pages. */ if (!(vma->vm_flags & VM_SHARED)) vm_flags_clear(vma, VM_MAYWRITE);
pr_debug("map %d+%d at %lx (pgoff %lx)\n", index, count, vma->vm_start, vma->vm_pgoff);
mutex_lock(&priv->lock); map = gntdev_find_map_index(priv, index, count); if (!map) goto unlock_out; if (!atomic_add_unless(&map->in_use, 1, 1)) goto unlock_out;
refcount_inc(&map->users);
vma->vm_ops = &gntdev_vmops;
vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP);
if (xen_pv_domain()) vm_flags_set(vma, VM_DONTCOPY);
vma->vm_private_data = map; if (map->flags) { if ((vma->vm_flags & VM_WRITE) && (map->flags & GNTMAP_readonly)) goto out_unlock_put; } else { map->flags = GNTMAP_host_map; if (!(vma->vm_flags & VM_WRITE)) map->flags |= GNTMAP_readonly; }
map->pages_vm_start = vma->vm_start;
if (xen_pv_domain()) { err = mmu_interval_notifier_insert_locked( &map->notifier, vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, &gntdev_mmu_ops); if (err) goto out_unlock_put;
map->notifier_init = true; } mutex_unlock(&priv->lock);
if (xen_pv_domain()) { /* * gntdev takes the address of the PTE in find_grant_ptes() and * passes it to the hypervisor in gntdev_map_grant_pages(). The * purpose of the notifier is to prevent the hypervisor pointer * to the PTE from going stale. * * Since this vma's mappings can't be touched without the * mmap_lock, and we are holding it now, there is no need for * the notifier_range locking pattern. */ mmu_interval_read_begin(&map->notifier);
err = apply_to_page_range(vma->vm_mm, vma->vm_start, vma->vm_end - vma->vm_start, find_grant_ptes, map); if (err) { pr_warn("find_grant_ptes() failure.\n"); goto out_put_map; } }
err = gntdev_map_grant_pages(map); if (err) goto out_put_map;
if (!xen_pv_domain()) { err = vm_map_pages_zero(vma, map->pages, map->count); if (err) goto out_put_map; }
return 0;
unlock_out: mutex_unlock(&priv->lock); return err;
out_unlock_put: mutex_unlock(&priv->lock);out_put_map: if (xen_pv_domain()) unmap_grant_pages(map, 0, map->count); gntdev_put_map(priv, map); return err;}
static const struct file_operations gntdev_fops = { .owner = THIS_MODULE, .open = gntdev_open, .release = gntdev_release, .mmap = gntdev_mmap, .unlocked_ioctl = gntdev_ioctl};
static struct miscdevice gntdev_miscdev = { .minor = MISC_DYNAMIC_MINOR, .name = "xen/gntdev", .fops = &gntdev_fops,};
/* ------------------------------------------------------------------ */
static int __init gntdev_init(void){ int err;
if (!xen_domain()) return -ENODEV;
err = misc_register(&gntdev_miscdev); if (err != 0) { pr_err("Could not register gntdev device\n"); return err; } return 0;}
static void __exit gntdev_exit(void){ misc_deregister(&gntdev_miscdev);}
module_init(gntdev_init);module_exit(gntdev_exit);
/* ------------------------------------------------------------------ */