linux-toradex.git/drivers/xen/gntdev.c, branch v4.9.60

xen/gntdev: avoid out of bounds access in case of partial gntdev_mmap()

2017-11-02T08:49:13+00:00

commit 298d275d4d9bea3524ff4bc76678c140611d8a8d upstream.

In case gntdev_mmap() succeeds only partially in mapping grant pages
it will leave some vital information uninitialized needed later for
cleanup. This will lead to an out of bounds array access when unmapping
the already mapped pages.

So just initialize the data needed for unmapping the pages a little bit
earlier.

Reported-by: Arthur Borsboom 
Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky 
Signed-off-by: Greg Kroah-Hartman

xen/gntdev: Use VM_MIXEDMAP instead of VM_IO to avoid NUMA balancing

2017-01-06T09:40:17+00:00

commit 30faaafdfa0c754c91bac60f216c9f34a2bfdf7e upstream.

Commit 9c17d96500f7 ("xen/gntdev: Grant maps should not be subject to
NUMA balancing") set VM_IO flag to prevent grant maps from being
subjected to NUMA balancing.

It was discovered recently that this flag causes get_user_pages() to
always fail with -EFAULT.

check_vma_flags
__get_user_pages
__get_user_pages_locked
__get_user_pages_unlocked
get_user_pages_fast
iov_iter_get_pages
dio_refill_pages
do_direct_IO
do_blockdev_direct_IO
do_blockdev_direct_IO
ext4_direct_IO_read
generic_file_read_iter
aio_run_iocb

(which can happen if guest's vdisk has direct-io-safe option).

To avoid this let's use VM_MIXEDMAP flag instead --- it prevents
NUMA balancing just as VM_IO does and has no effect on
check_vma_flags().


Reported-by: Olaf Hering 
Suggested-by: Hugh Dickins 
Signed-off-by: Boris Ostrovsky 
Acked-by: Hugh Dickins 
Tested-by: Olaf Hering 
Signed-off-by: Juergen Gross 
Signed-off-by: Greg Kroah-Hartman

xen: use vma_pages().

2016-07-06T09:34:47+00:00

Replace explicit computation of vma page count by a call to
vma_pages().

Signed-off-by: Muhammad Falak R Wani 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: David Vrabel

xen/gntdev: reduce copy batch size to 16

2016-05-24T11:58:17+00:00

IOCTL_GNTDEV_GRANT_COPY batches copy operations to reduce the number
of hypercalls.  The stack is used to avoid a memory allocation in a
hot path. However, a batch size of 24 requires more than 1024 bytes of
stack which in some configurations causes a compiler warning.

    xen/gntdev.c: In function ‘gntdev_ioctl_grant_copy’:
    xen/gntdev.c:949:1: warning: the frame size of 1248 bytes is
    larger than 1024 bytes [-Wframe-larger-than=]

This is a harmless warning as there is still plenty of stack spare,
but people keep trying to "fix" it.  Reduce the batch size to 16 to
reduce stack usage to less than 1024 bytes.  This should have minimal
impact on performance.

Signed-off-by: David Vrabel

xen/gntdev: add ioctl for grant copy

2016-01-07T13:21:53+00:00

Add IOCTL_GNTDEV_GRANT_COPY to allow applications to copy between user
space buffers and grant references.

This interface is similar to the GNTTABOP_copy hypercall ABI except
the local buffers are provided using a virtual address (instead of a
GFN and offset).  To avoid userspace from having to page align its
buffers the driver will use two or more ops if required.

If the ioctl returns 0, the application must check the status of each
segment with the segments status field.  If the ioctl returns a -ve
error code (EINVAL or EFAULT), the status of individual ops is
undefined.

Signed-off-by: David Vrabel 
Reviewed-by: Boris Ostrovsky

xen/gntdev: constify mmu_notifier_ops structures

2015-12-21T14:41:01+00:00

This mmu_notifier_ops structure is never modified, so declare it as
const, like the other mmu_notifier_ops structures.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall 
Signed-off-by: David Vrabel

xen/gntdev: Grant maps should not be subject to NUMA balancing

2015-11-26T17:47:35+00:00

Doing so will cause the grant to be unmapped and then, during
fault handling, the fault to be mistakenly treated as NUMA hint
fault.

In addition, even if those maps could partcipate in NUMA
balancing, it wouldn't provide any benefit since we are unable
to determine physical page's node (even if/when VNUMA is
implemented).

Marking grant maps' VMAs as VM_IO will exclude them from being
part of NUMA balancing.

Signed-off-by: Boris Ostrovsky 
Cc: stable@vger.kernel.org
Signed-off-by: David Vrabel

mm: mark most vm_operations_struct const

2015-09-10T20:29:01+00:00

With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct
structs should be constant.

Signed-off-by: Kirill A. Shutemov 
Reviewed-by: Oleg Nesterov 
Cc: "H. Peter Anvin" 
Cc: Andy Lutomirski 
Cc: Dave Hansen 
Cc: Ingo Molnar 
Cc: Minchan Kim 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

xen/gntdevt: Fix race condition in gntdev_release()

2015-06-30T15:57:32+00:00

While gntdev_release() is called the MMU notifier is still registered
and can traverse priv->maps list even if no pages are mapped (which is
the case -- gntdev_release() is called after all). But
gntdev_release() will clear that list, so make sure that only one of
those things happens at the same time.

Signed-off-by: Marek Marczykowski-Górecki 
Cc: 
Signed-off-by: David Vrabel

xen: Include xen/page.h rather than asm/xen/page.h

2015-06-17T15:14:18+00:00

Using xen/page.h will be necessary later for using common xen page
helpers.

As xen/page.h already include asm/xen/page.h, always use the later.

Signed-off-by: Julien Grall 
Reviewed-by: David Vrabel 
Cc: Stefano Stabellini 
Cc: Ian Campbell 
Cc: Wei Liu 
Cc: Konrad Rzeszutek Wilk 
Cc: Boris Ostrovsky 
Cc: netdev@vger.kernel.org
Signed-off-by: David Vrabel