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authorMike Kravetz <mike.kravetz@oracle.com>2017-02-23 00:43:04 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 01:41:28 +0100
commitcab350afcbc9c8a744e0d164d1c26560568f770b (patch)
tree57eb4021a19e2cd735454a85de03f271ebcb826d /fs/userfaultfd.c
parentuserfaultfd: hugetlbfs: add userfaultfd hugetlb hook (diff)
downloadlinux-cab350afcbc9c8a744e0d164d1c26560568f770b.tar.xz
linux-cab350afcbc9c8a744e0d164d1c26560568f770b.zip
userfaultfd: hugetlbfs: allow registration of ranges containing huge pages
Expand the userfaultfd_register/unregister routines to allow VM_HUGETLB vmas. huge page alignment checking is performed after a VM_HUGETLB vma is encountered. Also, since there is no UFFDIO_ZEROPAGE support for huge pages do not return that as a valid ioctl method for huge page ranges. Link: http://lkml.kernel.org/r/20161216144821.5183-22-aarcange@redhat.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/userfaultfd.c')
-rw-r--r--fs/userfaultfd.c55
1 files changed, 50 insertions, 5 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 26e1ef00b63c..5139d05f80e6 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -27,6 +27,7 @@
#include <linux/mempolicy.h>
#include <linux/ioctl.h>
#include <linux/security.h>
+#include <linux/hugetlb.h>
static struct kmem_cache *userfaultfd_ctx_cachep __read_mostly;
@@ -1058,6 +1059,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
struct uffdio_register __user *user_uffdio_register;
unsigned long vm_flags, new_flags;
bool found;
+ bool huge_pages;
unsigned long start, end, vma_end;
user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1109,6 +1111,17 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
goto out_unlock;
/*
+ * If the first vma contains huge pages, make sure start address
+ * is aligned to huge page size.
+ */
+ if (is_vm_hugetlb_page(vma)) {
+ unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
+
+ if (start & (vma_hpagesize - 1))
+ goto out_unlock;
+ }
+
+ /*
* Search for not compatible vmas.
*
* FIXME: this shall be relaxed later so that it doesn't fail
@@ -1116,6 +1129,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
* on anonymous vmas).
*/
found = false;
+ huge_pages = false;
for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {
cond_resched();
@@ -1124,8 +1138,21 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
/* check not compatible vmas */
ret = -EINVAL;
- if (!vma_is_anonymous(cur))
+ if (!vma_is_anonymous(cur) && !is_vm_hugetlb_page(cur))
goto out_unlock;
+ /*
+ * If this vma contains ending address, and huge pages
+ * check alignment.
+ */
+ if (is_vm_hugetlb_page(cur) && end <= cur->vm_end &&
+ end > cur->vm_start) {
+ unsigned long vma_hpagesize = vma_kernel_pagesize(cur);
+
+ ret = -EINVAL;
+
+ if (end & (vma_hpagesize - 1))
+ goto out_unlock;
+ }
/*
* Check that this vma isn't already owned by a
@@ -1138,6 +1165,12 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
cur->vm_userfaultfd_ctx.ctx != ctx)
goto out_unlock;
+ /*
+ * Note vmas containing huge pages
+ */
+ if (is_vm_hugetlb_page(cur))
+ huge_pages = true;
+
found = true;
}
BUG_ON(!found);
@@ -1149,7 +1182,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
do {
cond_resched();
- BUG_ON(!vma_is_anonymous(vma));
+ BUG_ON(!vma_is_anonymous(vma) && !is_vm_hugetlb_page(vma));
BUG_ON(vma->vm_userfaultfd_ctx.ctx &&
vma->vm_userfaultfd_ctx.ctx != ctx);
@@ -1207,7 +1240,8 @@ out_unlock:
* userland which ioctls methods are guaranteed to
* succeed on this range.
*/
- if (put_user(UFFD_API_RANGE_IOCTLS,
+ if (put_user(huge_pages ? UFFD_API_RANGE_IOCTLS_HPAGE :
+ UFFD_API_RANGE_IOCTLS,
&user_uffdio_register->ioctls))
ret = -EFAULT;
}
@@ -1254,6 +1288,17 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
goto out_unlock;
/*
+ * If the first vma contains huge pages, make sure start address
+ * is aligned to huge page size.
+ */
+ if (is_vm_hugetlb_page(vma)) {
+ unsigned long vma_hpagesize = vma_kernel_pagesize(vma);
+
+ if (start & (vma_hpagesize - 1))
+ goto out_unlock;
+ }
+
+ /*
* Search for not compatible vmas.
*
* FIXME: this shall be relaxed later so that it doesn't fail
@@ -1275,7 +1320,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
* provides for more strict behavior to notice
* unregistration errors.
*/
- if (!vma_is_anonymous(cur))
+ if (!vma_is_anonymous(cur) && !is_vm_hugetlb_page(cur))
goto out_unlock;
found = true;
@@ -1289,7 +1334,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
do {
cond_resched();
- BUG_ON(!vma_is_anonymous(vma));
+ BUG_ON(!vma_is_anonymous(vma) && !is_vm_hugetlb_page(vma));
/*
* Nothing to do: this vma is already registered into this