xen-blkback: print stats about persistent grants

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: use balloon pages for all mappings

Using balloon pages for all granted pages allows us to simplify the
logic in blkback, especially in the xen_blkbk_map function, since now
we can decide if we want to map a grant persistently or not after we
have actually mapped it. This could not be done before because
persistent grants used ballooned pages, whereas non-persistent grants
used pages from the kernel.

This patch also introduces several changes, the first one is that the
list of free pages is no longer global, now each blkback instance has
it's own list of free pages that can be used to map grants. Also, a
run time parameter (max_buffer_pages) has been added in order to tune
the maximum number of free pages each blkback instance will keep in
it's buffer.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: implement LRU mechanism for persistent grants

This mechanism allows blkback to change the number of grants
persistently mapped at run time.

The algorithm uses a simple LRU mechanism that removes (if needed) the
persistent grants that have not been used since the last LRU run, or
if all grants have been used it removes the first grants in the list
(that are not in use).

The algorithm allows the user to change the maximum number of
persistent grants, by changing max_persistent_grants in sysfs.

Since we are storing the persistent grants used inside the request
struct (to be able to mark them as "unused" when unmapping), we no
longer need the bitmap (unmap_seg).

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: move pending handles list from blkbk to pending_req

Moving grant ref handles from blkbk to pending_req will allow us to
get rid of the shared blkbk structure.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: make the queue of free requests per backend

Remove the last dependency from blkbk by moving the list of free
requests to blkif. This change reduces the contention on the list of
available requests.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: expand map/unmap functions

Preparatory change for implementing indirect descriptors. Change
xen_blkbk_{map/unmap} in order to be able to map/unmap a random amount
of grants (previously it was limited to
BLKIF_MAX_SEGMENTS_PER_REQUEST). Also, remove the usage of pending_req
in the map/unmap functions, so we can map/unmap grants without needing
to pass a pending_req.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-block: implement indirect descriptors

Indirect descriptors introduce a new block operation
(BLKIF_OP_INDIRECT) that passes grant references instead of segments
in the request. This grant references are filled with arrays of
blkif_request_segment_aligned, this way we can send more segments in a
request.

The proposed implementation sets the maximum number of indirect grefs
(frames filled with blkif_request_segment_aligned) to 256 in the
backend and 32 in the frontend. The value in the frontend has been
chosen experimentally, and the backend value has been set to a sane
value that allows expanding the maximum number of indirect descriptors
in the frontend if needed.

The migration code has changed from the previous implementation, in
which we simply remapped the segments on the shared ring. Now the
maximum number of segments allowed in a request can change depending
on the backend, so we have to requeue all the requests in the ring and
in the queue and split the bios in them if they are bigger than the
new maximum number of segments.

[v2: Fixed minor comments by Konrad.
[v1: Added padding to make the indirect request 64bit aligned.
 Added some BUGs, comments; fixed number of indirect pages in
 blkif_get_x86_{32/64}_req. Added description about the indirect operation
 in blkif.h]
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
[v3: Fixed spaces and tabs mix ups]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: allocate list of pending reqs in small chunks

Allocate pending requests in smaller chunks instead of allocating them
all at the same time.

This change also removes the global array of pending_reqs, it is no
longer necessay.

Variables related to the grant mapping have been grouped into a struct
called "grant_page", this allows to allocate them in smaller chunks,
and also improves memory locality.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkfront: use a different scatterlist for each request

In blkif_queue_request blkfront iterates over the scatterlist in order
to set the segments of the request, and in blkif_completion blkfront
iterates over the raw request, which makes it hard to know the exact
position of the source and destination memory positions.

This can be solved by allocating a scatterlist for each request, that
will be keep until the request is finished, allowing us to copy the
data back to the original memory without having to iterate over the
raw request.

Oracle-Bug: 16660413 - LARGE ASYNCHRONOUS READS APPEAR BROKEN ON 2.6.39-400
CC: stable@vger.kernel.org
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-and-Tested-by: Anne Milicia <anne.milicia@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkfront: Introduce a 'max' module parameter to alter the amount of indirect segments.

The max module parameter (by default 32) is the maximum number of
segments that the frontend will negotiate with the backend for indirect
descriptors.  Higher value means more potential throughput but more
memory usage. The backend picks the minimum of the frontend and its
default backend value.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback/sysfs: Move the parameters for the persistent grant features

to a testing subdirectory (as this value should not be baked
for the life-time) and also in an appropiate file.

Also modified the introduction Linux version from 3.10 to 3.11.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/blkback: Use physical sector size for setup

Currently xen-blkback passes the logical sector size over xenbus and
xen-blkfront sets up the paravirt disk with that logical block size.
But newer drives usually have the logical sector size set to 512 for
compatibility reasons and would show the actual sector size only in
physical sector size.
This results in the device being partitioned and accessed in dom0 with
the correct sector size, but the guest thinks 512 bytes is the correct
block size. And that results in poor performance.

To fix this, blkback gets modified to pass also physical-sector-size
over xenbus and blkfront to use both values to set up the paravirt
disk. I did not just change the passed in sector-size because I am
not sure having a bigger logical sector size than the physical one
is valid (and that would happen if a newer dom0 kernel hits an older
domU kernel). Also this way a domU set up before should still be
accessible (just some tools might detect the unaligned setup).

[v2: Make xenbus write failure non-fatal]
[v3: Use xenbus_scanf instead of xenbus_gather]
[v4: Rebased against segment changes]

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen/blkback: Check device permissions before allowing OP_DISCARD

We need to make sure that the device is not RO or that
the request is not past the number of sectors we want to
issue the DISCARD operation for.

This fixes CVE-2013-2140.

Cc: stable@vger.kernel.org
Acked-by: Jan Beulich <JBeulich@suse.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
[v1: Made it pr_warn instead of pr_debug]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
drm/radeon: fix UVD on big endian

This fixes the kernel side so that the ring should come
up and ring and IB tests should work.  The userspace
UVD drivers will also need big endian fixes.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/radeon: fix AVI infoframe generation

- remove adding 2 to checksum, this is incorrect.

This was incorrectly introduced in:
92db7f6c860b8190571a9dc1fcbc16d003422fe8
http://lists.freedesktop.org/archives/dri-devel/2011-December/017717.html
However, the off by 2 was due to adding the version twice.
From the examples in the URL above:

[Rafał Miłecki][RV620] fglrx:
0x7454: 00 A8 5E 79     R600_HDMI_VIDEOINFOFRAME_0
0x7458: 00 28 00 10     R600_HDMI_VIDEOINFOFRAME_1
0x745C: 00 48 00 28     R600_HDMI_VIDEOINFOFRAME_2
0x7460: 02 00 00 48     R600_HDMI_VIDEOINFOFRAME_3
===================
(0x82 + 0x2 + 0xD) + 0x1F8 = 0x289
-0x289 = 0x77

However, the payload sum is not 0x1f8, it's 0x1f6.
00 + A8 + 5E + 00 +
00 + 28 + 00 + 10 +
00 + 48 + 00 + 28 +
00 + 48 =
0x1f6

Bits 25:24 of HDMI_VIDEOINFOFRAME_3 are the packet version, not part
of the payload.  So the total would be:
(0x82 + 0x2 + 0xD) + 0x1f6 = 0x287
-0x287 = 0x79

- properly emit the AVI infoframe version.  This was not being
emitted previous which is probably what caused the issue above.

This should fix blank screen when HDMI audio is enabled on
certain monitors.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Cc: Rafał Miłecki <zajec5@gmail.com>
drm/radeon: add backlight quirk for hybrid mac

Mac laptops with multiple GPUs apparently use the gmux
driver for backlight control.  Don't register a radeon
backlight interface.  We may need to add other pci ids
for other hybrid mac laptops.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=65377

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
OMAPDSS: add pdata->default_display_name

We can currently set the default display (i.e. the initial display) in
the omapdss platform data by using a pointer to the default
omap_dss_device. Internally omapdss uses the device's name to resolve
the default display.

As it's difficult to get the omap_dss_device pointer in the future,
after we've changed the omapdss device model, this patch adds a new way
to define the default display, by using the name of the display.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Archit Taneja <archit@ti.com>
OMAPDSS: only probe pdata if there's one

omapdss output drivers always read the platform data. This crashes when
there's no platform data when using DT.

Add a check to read the platform data only if it exists.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
OMAPDSS: add omap_dss_find_output()

Add a support function to find a DSS output by given name. This is used
in later patches to link the panels to DSS outputs.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
OMAPDSS: add omap_dss_find_output_by_node()

Add a support function to find a DSS output by given DT node. This is
used in later patches to link the panels to DSS outputs.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>