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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/2] xen/privcmd: add PRIVCMD_MMAPBATCH_V2 ioctl
From: David Vrabel <david.vrabel@xxxxxxxxxx>
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.
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
drivers/xen/privcmd.c | 78 +++++++++++++++++++++++++++++++++++++-----------
include/xen/privcmd.h | 21 ++++++++++++-
2 files changed, 80 insertions(+), 19 deletions(-)
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index ccee0f1..ddd32cf 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -248,18 +248,23 @@ struct mmap_batch_state {
struct vm_area_struct *vma;
int err;
- xen_pfn_t __user *user;
+ xen_pfn_t __user *user_mfn;
+ int __user *user_err;
};
static int mmap_batch_fn(void *data, void *state)
{
xen_pfn_t *mfnp = data;
+ int *err = 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);
+ if (ret < 0) {
+ *err = ret;
+ if (st->err == 0 || st->err == -ENOENT)
+ st->err = ret;
}
st->va += PAGE_SIZE;
@@ -268,18 +273,30 @@ static int mmap_batch_fn(void *data, void *state)
static int mmap_return_errors(void *data, void *state)
{
- xen_pfn_t *mfnp = data;
+ int *err = data;
struct mmap_batch_state *st = state;
+ int ret;
+
+ if (st->user_err)
+ return __put_user(*err, st->user_err++);
+ else {
+ xen_pfn_t mfn;
- return put_user(*mfnp, st->user++);
+ ret = __get_user(mfn, st->user_mfn);
+ if (ret < 0)
+ return ret;
+
+ mfn |= PRIVCMD_MMAPBATCH_MFN_ERROR;
+ return __put_user(mfn, 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;
@@ -289,15 +306,32 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
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);
+ (xen_pfn_t *)m.arr);
if (ret || list_empty(&pagelist))
goto out;
@@ -325,12 +359,16 @@ static long privcmd_ioctl_mmap_batch(void __user *udata)
up_write(&mm->mmap_sem);
- if (state.err > 0) {
- state.user = m.arr;
+ if (state.err) {
+ state.user_mfn = (xen_pfn_t *)m.arr;
+ state.user_err = m.err;
ret = traverse_pages(m.num, sizeof(xen_pfn_t),
- &pagelist,
- mmap_return_errors, &state);
- }
+ &pagelist,
+ mmap_return_errors, &state);
+ if (!ret)
+ ret = state.err;
+ } else if (m.err)
+ __clear_user(m.err, m.num * sizeof(*m.err));
out:
free_page_list(&pagelist);
@@ -354,7 +392,11 @@ 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:
diff --git a/include/xen/privcmd.h b/include/xen/privcmd.h
index 17857fb..37e5255 100644
--- a/include/xen/privcmd.h
+++ b/include/xen/privcmd.h
@@ -59,13 +59,30 @@ struct privcmd_mmapbatch {
int num; /* number of pages to populate */
domid_t dom; /* target domain */
__u64 addr; /* virtual address */
- xen_pfn_t __user *arr; /* array of mfns - top nibble set on err */
+ xen_pfn_t __user *arr; /* array of mfns - or'd with
+ PRIVCMD_MMAPBATCH_MFN_ERROR on err */
+};
+
+#define PRIVCMD_MMAPBATCH_MFN_ERROR 0xf0000000U
+
+struct privcmd_mmapbatch_v2 {
+ unsigned int num; /* number of pages to populate */
+ domid_t dom; /* target domain */
+ __u64 addr; /* virtual address */
+ const xen_pfn_t __user *arr; /* array of mfns */
+ int __user *err; /* array of error codes */
};
/*
* @cmd: IOCTL_PRIVCMD_HYPERCALL
* @arg: &privcmd_hypercall_t
* Return: Value returned from execution of the specified hypercall.
+ *
+ * @cmd: IOCTL_PRIVCMD_MMAPBATCH_V2
+ * @arg: &struct privcmd_mmapbatch_v2
+ * Return: 0 if all pages were mapped successfully. -ENOENT if all
+ * failed mappings returned -ENOENT, otherwise the error code of the
+ * first failed mapping.
*/
#define IOCTL_PRIVCMD_HYPERCALL \
_IOC(_IOC_NONE, 'P', 0, sizeof(struct privcmd_hypercall))
@@ -73,5 +90,7 @@ struct privcmd_mmapbatch {
_IOC(_IOC_NONE, 'P', 2, sizeof(struct privcmd_mmap))
#define IOCTL_PRIVCMD_MMAPBATCH \
_IOC(_IOC_NONE, 'P', 3, sizeof(struct privcmd_mmapbatch))
+#define IOCTL_PRIVCMD_MMAPBATCH_V2 \
+ _IOC(_IOC_NONE, 'P', 4, sizeof(struct privcmd_mmapbatch_v2))
#endif /* __LINUX_PUBLIC_PRIVCMD_H__ */
--
1.7.2.5
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