linux.git/drivers/xen/gntdev.c, branch v5.13.4

xen/gntdev: fix gntdev_mmap() error exit path

2021-05-10T07:32:00+00:00

Commit d3eeb1d77c5d0af ("xen/gntdev: use mmu_interval_notifier_insert")
introduced an error in gntdev_mmap(): in case the call of
mmu_interval_notifier_insert_locked() fails the exit path should not
call mmu_interval_notifier_remove(), as this might result in NULL
dereferences.

One reason for failure is e.g. a signal pending for the running
process.

Fixes: d3eeb1d77c5d0af ("xen/gntdev: use mmu_interval_notifier_insert")
Cc: stable@vger.kernel.org
Reported-by: Marek Marczykowski-Górecki 
Tested-by: Marek Marczykowski-Górecki 
Signed-off-by: Juergen Gross 
Reviewed-by: Luca Fancellu 
Link: https://lore.kernel.org/r/20210423054038.26696-1-jgross@suse.com
Signed-off-by: Juergen Gross

Xen/gntdev: don't needlessly use kvcalloc()

2021-03-10T22:39:29+00:00

Requesting zeroed memory when all of it will be overwritten subsequently
by all ones is a waste of processing bandwidth. In fact, rather than
recording zeroed ->grants[], fill that array too with more appropriate
"invalid" indicators.

Signed-off-by: Jan Beulich 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/9a726be2-4893-8ffe-0ef1-b70dd1c229b1@suse.com
Signed-off-by: Boris Ostrovsky

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

2021-03-10T22:39:29+00:00

It's not helpful if every driver has to cook its own. Generalize
xenbus'es INVALID_GRANT_HANDLE and pcifront's INVALID_GRANT_REF (which
shouldn't have expanded to zero to begin with). Use the constants in
p2m.c and gntdev.c right away, and update field types where necessary so
they would match with the constants' types (albeit without touching
struct ioctl_gntdev_grant_ref's ref field, as that's part of the public
interface of the kernel and would require introducing a dependency on
Xen's grant_table.h public header).

Signed-off-by: Jan Beulich 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/db7c38a5-0d75-d5d1-19de-e5fe9f0b9c48@suse.com
Signed-off-by: Boris Ostrovsky

Xen/gntdev: don't needlessly allocate k{,un}map_ops[]

2021-03-10T22:39:29+00:00

They're needed only in the not-auto-translate (i.e. PV) case; there's no
point in allocating memory that's never going to get accessed.

Signed-off-by: Jan Beulich 
Reviewed-by: Juergen Gross 
Link: https://lore.kernel.org/r/180d50cb-5531-8952-4bf0-d65c554638ed@suse.com
Signed-off-by: Boris Ostrovsky

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

2021-02-15T07:52:27+00:00

Failure of the kernel part of the mapping operation should also be
indicated as an error to the caller, or else it may assume the
respective kernel VA is okay to access.

Furthermore gnttab_map_refs() failing still requires recording
successfully mapped handles, so they can be unmapped subsequently. This
in turn requires there to be a way to tell full hypercall failure from
partial success - preset map_op status fields such that they won't
"happen" to look as if the operation succeeded.

Also again use GNTST_okay instead of implying its value (zero).

This is part of XSA-361.

Signed-off-by: Jan Beulich 
Cc: stable@vger.kernel.org
Reviewed-by: Juergen Gross 
Signed-off-by: Juergen Gross

Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()

2021-02-15T07:51:07+00:00

We may not skip setting the field in the unmap structure when
GNTMAP_device_map is in use - such an unmap would fail to release the
respective resources (a page ref in the hypervisor). Otoh the field
doesn't need setting at all when GNTMAP_device_map is not in use.

To record the value for unmapping, we also better don't use our local
p2m: In particular after a subsequent change it may not have got updated
for all the batch elements. Instead it can simply be taken from the
respective map's results.

We can additionally avoid playing this game altogether for the kernel
part of the mappings in (x86) PV mode.

This is part of XSA-361.

Signed-off-by: Jan Beulich 
Cc: stable@vger.kernel.org
Reviewed-by: Stefano Stabellini 
Signed-off-by: Juergen Gross

xen/gntdev.c: Convert get_user_pages() to pin_user_pages()

2020-10-04T23:41:33+00:00

In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 5 as per document [1].

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
        https://lwn.net/Articles/807108/

Signed-off-by: Souptick Joarder 
Cc: John Hubbard 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: David Vrabel 
Link: https://lore.kernel.org/r/1599375114-32360-2-git-send-email-jrdr.linux@gmail.com
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

xen/gntdev.c: Mark pages as dirty

2020-10-04T23:39:18+00:00

There seems to be a bug in the original code when gntdev_get_page()
is called with writeable=true then the page needs to be marked dirty
before being put.

To address this, a bool writeable is added in gnt_dev_copy_batch, set
it in gntdev_grant_copy_seg() (and drop `writeable` argument to
gntdev_get_page()) and then, based on batch->writeable, use
set_page_dirty_lock().

Fixes: a4cdb556cae0 (xen/gntdev: add ioctl for grant copy)
Suggested-by: Boris Ostrovsky 
Signed-off-by: Souptick Joarder 
Cc: John Hubbard 
Cc: Boris Ostrovsky 
Cc: Juergen Gross 
Cc: David Vrabel 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/1599375114-32360-1-git-send-email-jrdr.linux@gmail.com
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Boris Ostrovsky

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

2020-06-09T16:39:14+00:00

This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.

The change is generated using coccinelle with the following rule:

// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Daniel Jordan 
Reviewed-by: Laurent Dufour 
Reviewed-by: Vlastimil Babka 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds

linux.git/drivers/xen/gntdev.c, branch v5.13.4

xen/gntdev: fix gntdev_mmap() error exit path

Xen/gntdev: don't needlessly use kvcalloc()

Xen/gnttab: introduce common INVALID_GRANT_{HANDLE,REF}

Xen/gntdev: don't needlessly allocate k{,un}map_ops[]

Xen/gntdev: correct error checking in gntdev_map_grant_pages()

Xen/gntdev: correct dev_bus_addr handling in gntdev_map_grant_pages()

xen/gntdev.c: Convert get_user_pages*() to pin_user_pages*()

xen/gntdev.c: Mark pages as dirty

mmap locking API: convert mmap_sem comments

mmap locking API: use coccinelle to convert mmap_sem rwsem call sites

xen/gntdev.c: Convert get_user_pages() to pin_user_pages()