qemu/util
Daniel P. Berrange 9dc44aa582 os: don't corrupt pre-existing memory-backend data with prealloc
When using a memory-backend object with prealloc turned on, QEMU
will memset() the first byte in every memory page to zero. While
this might have been acceptable for memory backends associated
with RAM, this corrupts application data for NVDIMMs.

Instead of setting every page to zero, read the current byte
value and then just write that same value back, so we are not
corrupting the original data. Directly write the value instead
of memset()ing it, since there's no benefit to memset for a
single byte write.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Message-id: 20170303113255.28262-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-03-15 11:55:41 +08:00
..
acl.c Drop Emacs local variables lists redundant with .dir-locals.el 2016-07-12 16:19:16 +02:00
aio-posix.c async: remove unnecessary inc/dec pairs 2017-02-21 11:39:40 +00:00
aio-win32.c async: remove unnecessary inc/dec pairs 2017-02-21 11:39:40 +00:00
aiocb.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
async.c cpus: define QEMUTimerListNotifyCB for QEMU system emulation 2017-03-14 13:28:29 +01:00
base64.c include/qemu/osdep.h: Don't include qapi/error.h 2016-03-22 22:20:15 +01:00
bitmap.c bitmap: assert that start and nr are non negative 2017-01-20 13:22:17 +01:00
bitops.c util: Clean up includes 2016-02-04 17:01:04 +00:00
buffer.c qemu-common: stop including qemu/host-utils.h from qemu-common.h 2016-05-19 16:42:28 +02:00
bufferiszero.c cutils: Rewrite x86 buffer zero checking 2016-09-14 12:25:14 +02:00
compatfd.c cpus: remove ugly cast on sigbus_handler 2017-03-03 16:40:02 +01:00
coroutine-gthread.c all: Remove unnecessary glib.h includes 2016-06-07 18:19:24 +03:00
coroutine-sigaltstack.c coroutine-sigaltstack: use helper for allocating stack memory 2016-09-29 14:13:39 +02:00
coroutine-ucontext.c coroutine-ucontext: use helper for allocating stack memory 2016-09-29 14:13:39 +02:00
coroutine-win32.c coroutine: add a macro for the coroutine stack size 2016-09-29 14:13:39 +02:00
crc32c.c util: Clean up includes 2016-02-04 17:01:04 +00:00
cutils.c util/cutils: Change qemu_strtosz*() from int64_t to uint64_t 2017-02-23 20:35:36 +01:00
envlist.c util: Clean up includes 2016-02-04 17:01:04 +00:00
error.c migration: add reporting of errors for outgoing migration 2016-05-26 11:31:30 +05:30
event_notifier-posix.c event_notifier: cleanups around event_notifier_set_handler 2017-01-16 17:52:35 +01:00
event_notifier-win32.c event_notifier: cleanups around event_notifier_set_handler 2017-01-16 17:52:35 +01:00
fifo8.c migration: consolidate VMStateField.start 2017-02-13 17:27:13 +00:00
getauxval.c util: Clean up includes 2016-02-04 17:01:04 +00:00
hbitmap.c hbitmap: Add hbitmap_is_serializable() 2017-01-26 10:25:01 +08:00
hexdump.c util: Improved qemu_hexmap() to include an ascii dump of the buffer 2016-04-06 09:52:07 +08:00
host-utils.c host-utils: Implement unsigned quadword left/right shift and unit tests 2017-01-31 10:10:14 +11:00
id.c util: move declarations out of qemu-common.h 2016-03-22 22:20:17 +01:00
iohandler.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
iov.c util: Fix assertion in iov_copy() upon zero 'bytes' and non-zero 'offset' 2016-08-03 18:44:57 +02:00
keyval.c keyval: Support lists 2017-03-07 16:07:48 +01:00
lockcnt.c qemu-thread: optimize QemuLockCnt with futexes on Linux 2017-01-16 13:25:18 +00:00
log.c util/cutils: Rename qemu_strtoll(), qemu_strtoull() 2017-02-23 20:35:35 +01:00
main-loop.c cpus: define QEMUTimerListNotifyCB for QEMU system emulation 2017-03-14 13:28:29 +01:00
Makefile.objs keyval: New keyval_parse() 2017-03-07 16:07:46 +01:00
memfd.c os-posix: include sys/mman.h 2016-06-16 18:39:03 +02:00
mmap-alloc.c exec, kvm, target-ppc: Move getrampagesize() to common code 2017-03-03 11:30:59 +11:00
module.c module: Don't load the same module if requested multiple times 2016-10-07 14:14:06 +02:00
notify.c util: Clean up includes 2016-02-04 17:01:04 +00:00
osdep.c osdep: Introduce qemu_dup 2016-07-13 13:26:02 +02:00
oslib-posix.c os: don't corrupt pre-existing memory-backend data with prealloc 2017-03-15 11:55:41 +08:00
oslib-win32.c mem-prealloc: reduce large guest start-up and migration time. 2017-03-14 13:26:36 +01:00
path.c util: Removed unneeded header from path.c 2017-03-14 13:26:37 +01:00
qdist.c qdist: return "(empty)" instead of NULL when printing an empty dist 2016-08-03 18:44:56 +02:00
qemu-config.c block: Add bdrv_runtime_opts to query-command-line-options 2016-10-07 13:34:07 +02:00
qemu-coroutine-io.c coroutine: move entry argument to qemu_coroutine_create 2016-07-13 13:26:02 +02:00
qemu-coroutine-lock.c coroutine-lock: make CoRwlock thread-safe and fair 2017-02-21 11:39:40 +00:00
qemu-coroutine-sleep.c block: explicitly acquire aiocontext in timers that need it 2017-02-21 11:14:08 +00:00
qemu-coroutine.c coroutine-lock: add limited spinning to CoMutex 2017-02-21 11:39:40 +00:00
qemu-error.c qemu-error: remove dependency of stubs on monitor 2016-11-01 16:06:57 +01:00
qemu-openpty.c util: Clean up includes 2016-02-04 17:01:04 +00:00
qemu-option.c option: Tweak invalid size error message and unbreak iotest 049 2017-02-28 20:40:31 +01:00
qemu-progress.c util: Clean up includes 2016-02-04 17:01:04 +00:00
qemu-sockets.c io: introduce a DNS resolver API 2017-01-23 15:32:46 +00:00
qemu-thread-posix.c * QOM interface fix (Eduardo) 2017-01-20 16:42:07 +00:00
qemu-thread-win32.c * QOM interface fix (Eduardo) 2017-01-20 16:42:07 +00:00
qemu-timer-common.c util: Clean up includes 2016-02-04 17:01:04 +00:00
qemu-timer.c icount: process QEMU_CLOCK_VIRTUAL timers in vCPU thread 2017-03-14 13:51:34 +01:00
qht.c qht: fix unlock-after-free segfault upon resizing 2016-10-06 18:04:13 +02:00
range.c range: Replace internal representation of Range 2016-07-04 16:49:33 +03:00
rcu.c rcu: simplify memory barriers 2016-10-24 11:30:56 +02:00
readline.c util: move declarations out of qemu-common.h 2016-03-22 22:20:17 +01:00
thread-pool.c block: explicitly acquire aiocontext in aio callbacks that need it 2017-02-21 11:39:39 +00:00
throttle.c throttle: Don't allow burst limits to be lower than the normal limits 2016-08-05 09:59:06 +01:00
timed-average.c Fix some typos found by codespell 2016-05-18 15:04:27 +03:00
trace-events coroutine-lock: make CoMutex thread-safe 2017-02-21 11:39:40 +00:00
unicode.c util: move declarations out of qemu-common.h 2016-03-22 22:20:17 +01:00
uri.c Fix documentation and some comments (article, grammar) 2017-01-24 23:26:52 +03:00
uuid.c uuid: Tighten uuid parse 2016-09-23 11:42:52 +08:00