Xen: Fix retry calls into PRIVCMD_MMAPBATCH*.
When a foreign mapper attempts to map guest frames that are paged out, the mapper receives an ENOENT response and will have to try again while a helper process pages the target frame back in. Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries of mapping calls. Permit subsequent calls to update a sub-range of the VMA, iff nothing is yet mapped in that range. Since it is now valid to call PRIVCMD_MMAPBATCH* multiple times, only set vma->vm_private_data if the parameters are valid and (if necessary) the pages for the auto_translated_physmap case have been allocated. This prevents subsequent calls from incorrectly entering the 'retry' path when there are no pages allocated etc. Signed-off-by: Andres Lagar-Cavilla <andres@lagarcavilla.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Родитель
669b0ae961
Коммит
a5deabe0e6
|
@ -43,9 +43,10 @@ MODULE_LICENSE("GPL");
|
|||
|
||||
#define PRIV_VMA_LOCKED ((void *)1)
|
||||
|
||||
#ifndef HAVE_ARCH_PRIVCMD_MMAP
|
||||
static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma);
|
||||
#endif
|
||||
static int privcmd_vma_range_is_mapped(
|
||||
struct vm_area_struct *vma,
|
||||
unsigned long addr,
|
||||
unsigned long nr_pages);
|
||||
|
||||
static long privcmd_ioctl_hypercall(void __user *udata)
|
||||
{
|
||||
|
@ -225,9 +226,9 @@ static long privcmd_ioctl_mmap(void __user *udata)
|
|||
vma = find_vma(mm, msg->va);
|
||||
rc = -EINVAL;
|
||||
|
||||
if (!vma || (msg->va != vma->vm_start) ||
|
||||
!privcmd_enforce_singleshot_mapping(vma))
|
||||
if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
|
||||
goto out_up;
|
||||
vma->vm_private_data = PRIV_VMA_LOCKED;
|
||||
}
|
||||
|
||||
state.va = vma->vm_start;
|
||||
|
@ -358,7 +359,7 @@ static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
|
|||
kfree(pages);
|
||||
return -ENOMEM;
|
||||
}
|
||||
BUG_ON(vma->vm_private_data != PRIV_VMA_LOCKED);
|
||||
BUG_ON(vma->vm_private_data != NULL);
|
||||
vma->vm_private_data = pages;
|
||||
|
||||
return 0;
|
||||
|
@ -421,19 +422,43 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
|
|||
|
||||
vma = find_vma(mm, m.addr);
|
||||
if (!vma ||
|
||||
vma->vm_ops != &privcmd_vm_ops ||
|
||||
(m.addr != vma->vm_start) ||
|
||||
((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) ||
|
||||
!privcmd_enforce_singleshot_mapping(vma)) {
|
||||
up_write(&mm->mmap_sem);
|
||||
vma->vm_ops != &privcmd_vm_ops) {
|
||||
ret = -EINVAL;
|
||||
goto out;
|
||||
goto out_unlock;
|
||||
}
|
||||
if (xen_feature(XENFEAT_auto_translated_physmap)) {
|
||||
ret = alloc_empty_pages(vma, m.num);
|
||||
if (ret < 0) {
|
||||
up_write(&mm->mmap_sem);
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* Caller must either:
|
||||
*
|
||||
* Map the whole VMA range, which will also allocate all the
|
||||
* pages required for the auto_translated_physmap case.
|
||||
*
|
||||
* Or
|
||||
*
|
||||
* Map unmapped holes left from a previous map attempt (e.g.,
|
||||
* because those foreign frames were previously paged out).
|
||||
*/
|
||||
if (vma->vm_private_data == NULL) {
|
||||
if (m.addr != vma->vm_start ||
|
||||
m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
|
||||
ret = -EINVAL;
|
||||
goto out_unlock;
|
||||
}
|
||||
if (xen_feature(XENFEAT_auto_translated_physmap)) {
|
||||
ret = alloc_empty_pages(vma, m.num);
|
||||
if (ret < 0)
|
||||
goto out_unlock;
|
||||
} else
|
||||
vma->vm_private_data = PRIV_VMA_LOCKED;
|
||||
} else {
|
||||
if (m.addr < vma->vm_start ||
|
||||
m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
|
||||
ret = -EINVAL;
|
||||
goto out_unlock;
|
||||
}
|
||||
if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
|
||||
ret = -EINVAL;
|
||||
goto out_unlock;
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -466,8 +491,11 @@ static long privcmd_ioctl_mmap_batch(void __user *udata, int version)
|
|||
|
||||
out:
|
||||
free_page_list(&pagelist);
|
||||
|
||||
return ret;
|
||||
|
||||
out_unlock:
|
||||
up_write(&mm->mmap_sem);
|
||||
goto out;
|
||||
}
|
||||
|
||||
static long privcmd_ioctl(struct file *file,
|
||||
|
@ -540,9 +568,24 @@ static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
|
|||
return 0;
|
||||
}
|
||||
|
||||
static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma)
|
||||
/*
|
||||
* For MMAPBATCH*. This allows asserting the singleshot mapping
|
||||
* on a per pfn/pte basis. Mapping calls that fail with ENOENT
|
||||
* can be then retried until success.
|
||||
*/
|
||||
static int is_mapped_fn(pte_t *pte, struct page *pmd_page,
|
||||
unsigned long addr, void *data)
|
||||
{
|
||||
return !cmpxchg(&vma->vm_private_data, NULL, PRIV_VMA_LOCKED);
|
||||
return pte_none(*pte) ? 0 : -EBUSY;
|
||||
}
|
||||
|
||||
static int privcmd_vma_range_is_mapped(
|
||||
struct vm_area_struct *vma,
|
||||
unsigned long addr,
|
||||
unsigned long nr_pages)
|
||||
{
|
||||
return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT,
|
||||
is_mapped_fn, NULL) != 0;
|
||||
}
|
||||
|
||||
const struct file_operations xen_privcmd_fops = {
|
||||
|
|
Загрузка…
Ссылка в новой задаче