diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/xen/gntdev.c | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index cbd3836ec8fa..dc495383ad73 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -748,6 +748,206 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) return rc; } +#define GNTDEV_COPY_BATCH 24 + +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; +}; + +static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt, + bool writeable, unsigned long *gfn) +{ + unsigned long addr = (unsigned long)virt; + struct page *page; + unsigned long xen_pfn; + int ret; + + ret = get_user_pages_fast(addr, 1, writeable, &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) +{ + unsigned int i; + + for (i = 0; i < batch->nr_pages; i++) + put_page(batch->pages[i]); + batch->nr_pages = 0; +} + +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); + + ret = gntdev_get_page(batch, virt, false, &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); + + ret = gntdev_get_page(batch, virt, true, &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; + + 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; + goto out; + } + + ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status); + if (ret < 0) + goto out; + + cond_resched(); + } + if (batch.nr_ops) + ret = gntdev_copy(&batch); + return ret; + + out: + gntdev_put_pages(&batch); + return ret; +} + static long gntdev_ioctl(struct file *flip, unsigned int cmd, unsigned long arg) { @@ -767,6 +967,9 @@ static long gntdev_ioctl(struct file *flip, case IOCTL_GNTDEV_SET_UNMAP_NOTIFY: return gntdev_ioctl_notify(priv, ptr); + case IOCTL_GNTDEV_GRANT_COPY: + return gntdev_ioctl_grant_copy(priv, ptr); + default: pr_debug("priv %p, unknown cmd %x\n", priv, cmd); return -ENOIOCTLCMD; |