Preparation for a followup patch "libs/guest: allocate various migration
arrays just once".
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
These lines (in mctelem_reserve)
newhead = oldhead->mcte_next;
if (cmpxchgptr(freelp, oldhead, newhead) == oldhead) {
are racy. After you read the newhead pointer it can happen that another
flow (thread or recursive invocation) change all the list but set head
with same value. So oldhead is the same as *freelp but you are setting
a new head that could point to whatever element (even already used).
This patch use instead a bit array and atomic bit operations.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Reviewed-by: Liu Jinsong <jinsong.liu@intel.com>
The function (mctelem_xchg_head()) used to exchange mce telemetry
list heads is racy. It may write to the head twice, with the second
write linking to an element in the wrong state.
If there are two threads, T1 inserting on committed list; and T2
trying to consume it.
1. T1 starts inserting an element (A), sets prev pointer (mcte_prev).
2. T1 is interrupted after the cmpxchg succeeded.
3. T2 gets the list and changes element A and updates the commit list
head.
4. T1 resumes, reads pointer to prev again and compare with result
from the cmpxchg which succeeded but in the meantime prev changed
in memory.
5. T1 thinks the cmpxchg failed and goes around the loop again,
linking head to A again.
To solve the race use temporary variable for prev pointer.
*linkp (which point to a field in the element) must be updated before
the cmpxchg() as after a successful cmpxchg the element might be
immediately removed and reinitialized.
The wmb() prior to the cmpchgptr() call is not necessary since it is
already a full memory barrier. This wmb() is thus removed.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Reviewed-by: Liu Jinsong <jinsong.liu@intel.com>
Split coverage informations extracted from xencov utility.
This script accept coverage blob either as file or from input and extract
into files compatible with gcc format (gcda).
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
This device was removed due to change in specifications.
Original patch written by Paul Durrant
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
First draft specification document it as a 64bit counter, now are a 128bit
value handled as a couple of 64bit values.
Allow to disable the device is values are all zeroes.
Add documentation for platform/generation-id key.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Operations are handled by a sysctl specific operation.
Implement 4 operations
- check if coverage is compiled in
- read size of coverage information
- read coverage information
- reset coverage counters
Information are stored in a single blob in a format specific to Xen designed
to make code that generate coverage as small as possible.
This patch add a public header with the structure of blob exported by Xen.
This avoid problems distributing header which is GPL2.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
This patch introduce coverage support to Xen.
Currently it allows to compile Xen with coverage support but there is no
way to extract them.
The declarations came from Linux source files (as you can see from file
headers).
The idea is to have some operations mainly
- get coverage information size
- read coverage information
- reset coverage counters
Linux use a file system to export these information. The information will
be a blob to handle with some tools (as usually tools require a bunch of
files but Xen does not handle files at all). I'll pack them to make things
simpler as possible.
These information cannot be put in a specific section (allowing a safe
mapping) as gcc use .rodata, .data, .text and .ctors sections.
I added code to handle constructors used in this case to initialize a
linked list of files.
I excluded %.init.o files as they are used before Xen start and should
not have section like .text or .data.
I used a "coverage" configuration option to mimic the "debug" one.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Apparently Windows 8 refuse to use any mode if has more than one page.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
Vesa specification require that mode information return if a given
mode is supported or not so test if we can support it checking
required memory and set correctly supported bit.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
Informations are stored in a structure that is smaller than final one.
Previous code copy this structure to stack extending with zeroes then
update it and copy to caller while now the not-extended version is
copied into stack and then is extended during copy reducing stack
usage.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
If you try to get mode information for an unsupported mode
interrupt should return error but not that the function is not
supported.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
Remove an overflow computing width x height x bit which does
not fit into a 16 bits. I wrote a routine to multiple these value
and get the size required for framebuffer in segment unit (64k).
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Committed-by: Keir Fraser <keir@xen.org>
Frediano Ziglio