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authorAndres Lagar-Cavilla <andreslc@gridcentric.ca>2012-08-31 09:59:30 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-09-05 16:36:26 -0400
commitceb90fa0a8008059ecbbf9114cb89dc71a730bb6 (patch)
tree0f0507ed14176b7e17508b551cd22fef722dde0a /drivers/xen
parent69870a847856a1ba81f655a8633fce5f5b614730 (diff)
xen/privcmd: add PRIVCMD_MMAPBATCH_V2 ioctl
PRIVCMD_MMAPBATCH_V2 extends PRIVCMD_MMAPBATCH with an additional field for reporting the error code for every frame that could not be mapped. libxc prefers PRIVCMD_MMAPBATCH_V2 over PRIVCMD_MMAPBATCH. Also expand PRIVCMD_MMAPBATCH to return appropriate error-encoding top nibble in the mfn array. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/privcmd.c130
1 files changed, 100 insertions, 30 deletions
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 85226cbeca2..92a285b1b96 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -76,7 +76,7 @@ static void free_page_list(struct list_head *pages)
*/
static int gather_array(struct list_head *pagelist,
unsigned nelem, size_t size,
- void __user *data)
+ const void __user *data)
{
unsigned pageidx;
void *pagedata;
@@ -246,61 +246,117 @@ struct mmap_batch_state {
domid_t domain;
unsigned long va;
struct vm_area_struct *vma;
- int err;
-
- xen_pfn_t __user *user;
+ /* A tristate:
+ * 0 for no errors
+ * 1 if at least one error has happened (and no
+ * -ENOENT errors have happened)
+ * -ENOENT if at least 1 -ENOENT has happened.
+ */
+ int global_error;
+ /* An array for individual errors */
+ int *err;
+
+ /* User-space mfn array to store errors in the second pass for V1. */
+ xen_pfn_t __user *user_mfn;
};
static int mmap_batch_fn(void *data, void *state)
{
xen_pfn_t *mfnp = data;
struct mmap_batch_state *st = state;
+ int ret;
- if (xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
- st->vma->vm_page_prot, st->domain) < 0) {
- *mfnp |= 0xf0000000U;
- st->err++;
+ ret = xen_remap_domain_mfn_range(st->vma, st->va & PAGE_MASK, *mfnp, 1,
+ st->vma->vm_page_prot, st->domain);
+
+ /* Store error code for second pass. */
+ *(st->err++) = ret;
+
+ /* And see if it affects the global_error. */
+ if (ret < 0) {
+ if (ret == -ENOENT)
+ st->global_error = -ENOENT;
+ else {
+ /* Record that at least one error has happened. */
+ if (st->global_error == 0)
+ st->global_error = 1;
+ }
}
st->va += PAGE_SIZE;
return 0;
}
-static int mmap_return_errors(void *data, void *state)
+static int mmap_return_errors_v1(void *data, void *state)
{
xen_pfn_t *mfnp = data;
struct mmap_batch_state *st = state;
-
- return put_user(*mfnp, st->user++);
+ int err = *(st->err++);
+
+ /*
+ * V1 encodes the error codes in the 32bit top nibble of the
+ * mfn (with its known limitations vis-a-vis 64 bit callers).
+ */
+ *mfnp |= (err == -ENOENT) ?
+ PRIVCMD_MMAPBATCH_PAGED_ERROR :
+ PRIVCMD_MMAPBATCH_MFN_ERROR;
+ return __put_user(*mfnp, st->user_mfn++);
}
static struct vm_operations_struct privcmd_vm_ops;
-static long privcmd_ioctl_mmap_batch(void __user *udata)
+static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
{
int ret;
- struct privcmd_mmapbatch m;
+ struct privcmd_mmapbatch_v2 m;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long nr_pages;
LIST_HEAD(pagelist);
+ int *err_array = NULL;
struct mmap_batch_state state;
if (!xen_initial_domain())
return -EPERM;
- if (copy_from_user(&m, udata, sizeof(m)))
- return -EFAULT;
+ switch (version) {
+ case 1:
+ if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
+ return -EFAULT;
+ /* Returns per-frame error in m.arr. */
+ m.err = NULL;
+ if (!access_ok(VERIFY_WRITE, m.arr, m.num * sizeof(*m.arr)))
+ return -EFAULT;
+ break;
+ case 2:
+ if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
+ return -EFAULT;
+ /* Returns per-frame error code in m.err. */
+ if (!access_ok(VERIFY_WRITE, m.err, m.num * (sizeof(*m.err))))
+ return -EFAULT;
+ break;
+ default:
+ return -EINVAL;
+ }
nr_pages = m.num;
if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
return -EINVAL;
- ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t),
- m.arr);
+ ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t), m.arr);
+
+ if (ret)
+ goto out;
+ if (list_empty(&pagelist)) {
+ ret = -EINVAL;
+ goto out;
+ }
- if (ret || list_empty(&pagelist))
+ err_array = kcalloc(m.num, sizeof(int), GFP_KERNEL);
+ if (err_array == NULL) {
+ ret = -ENOMEM;
goto out;
+ }
down_write(&mm->mmap_sem);
@@ -315,24 +371,34 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
goto out;
}
- state.domain = m.dom;
- state.vma = vma;
- state.va = m.addr;
- state.err = 0;
+ state.domain = m.dom;
+ state.vma = vma;
+ state.va = m.addr;
+ state.global_error = 0;
+ state.err = err_array;
- ret = traverse_pages(m.num, sizeof(xen_pfn_t),
- &pagelist, mmap_batch_fn, &state);
+ /* mmap_batch_fn guarantees ret == 0 */
+ BUG_ON(traverse_pages(m.num, sizeof(xen_pfn_t),
+ &pagelist, mmap_batch_fn, &state));
up_write(&mm->mmap_sem);
- if (state.err > 0) {
- state.user = m.arr;
+ if (state.global_error && (version == 1)) {
+ /* Write back errors in second pass. */
+ state.user_mfn = (xen_pfn_t *)m.arr;
+ state.err = err_array;
ret = traverse_pages(m.num, sizeof(xen_pfn_t),
- &pagelist,
- mmap_return_errors, &state);
- }
+ &pagelist, mmap_return_errors_v1, &state);
+ } else
+ ret = __copy_to_user(m.err, err_array, m.num * sizeof(int));
+
+ /* If we have not had any EFAULT-like global errors then set the global
+ * error to -ENOENT if necessary. */
+ if ((ret == 0) && (state.global_error == -ENOENT))
+ ret = -ENOENT;
out:
+ kfree(err_array);
free_page_list(&pagelist);
return ret;
@@ -354,7 +420,11 @@ static long privcmd_ioctl(struct file *file,
break;
case IOCTL_PRIVCMD_MMAPBATCH:
- ret = privcmd_ioctl_mmap_batch(udata);
+ ret = privcmd_ioctl_mmap_batch(udata, 1);
+ break;
+
+ case IOCTL_PRIVCMD_MMAPBATCH_V2:
+ ret = privcmd_ioctl_mmap_batch(udata, 2);
break;
default: