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qemu / qemu / 9dc44aa5829eb3131a01378a738dee28a382bbc1
commit9dc44aa5829eb3131a01378a738dee28a382bbc1[log] [tgz]
authorDaniel P. Berrange <berrange@redhat.com>Fri Mar 03 11:32:55 2017 +0000
committerStefan Hajnoczi <stefanha@redhat.com>Wed Mar 15 11:55:41 2017 +0800
tree7626e5cbbd351029d49c269a4291b60540beba1e
parentd84f714eafedd8bb9d4aaec8b76417bef8e3535e [diff]
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>
1 file changed
tree: 7626e5cbbd351029d49c269a4291b60540beba1e
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. chardev/
  6. contrib/
  7. crypto/
  8. default-configs/
  9. disas/
  10. docs/
  11. fpu/
  12. fsdev/
  13. gdb-xml/
  14. hw/
  15. include/
  16. io/
  17. libdecnumber/
  18. linux-headers/
  19. linux-user/
  20. migration/
  21. nbd/
  22. net/
  23. pc-bios/
  24. po/
  25. qapi/
  26. qga/
  27. qobject/
  28. qom/
  29. replay/
  30. roms/
  31. scripts/
  32. slirp/
  33. stubs/
  34. target/
  35. tcg/
  36. tests/
  37. trace/
  38. ui/
  39. util/
  40. dtc
  41. pixman
  42. .dir-locals.el
  43. .exrc
  44. .gitignore
  45. .gitmodules
  46. .mailmap
  47. .shippable.yml
  48. .travis.yml
  49. accel.c
  50. arch_init.c
  51. atomic_template.h
  52. balloon.c
  53. block.c
  54. blockdev-nbd.c
  55. blockdev.c
  56. blockjob.c
  57. bootdevice.c
  58. bt-host.c
  59. bt-vhci.c
  60. Changelog
  61. CODING_STYLE
  62. configure
  63. COPYING
  64. COPYING.LIB
  65. cpu-exec-common.c
  66. cpu-exec.c
  67. cpus-common.c
  68. cpus.c
  69. cputlb.c
  70. device-hotplug.c
  71. device_tree.c
  72. disas.c
  73. dma-helpers.c
  74. dump.c
  75. exec.c
  76. gdbstub.c
  77. HACKING
  78. hax-stub.c
  79. hmp-commands-info.hx
  80. hmp-commands.hx
  81. hmp.c
  82. hmp.h
  83. ioport.c
  84. iothread.c
  85. kvm-all.c
  86. kvm-stub.c
  87. LICENSE
  88. MAINTAINERS
  89. Makefile
  90. Makefile.objs
  91. Makefile.target
  92. memory.c
  93. memory_ldst.inc.c
  94. memory_mapping.c
  95. module-common.c
  96. monitor.c
  97. numa.c
  98. os-posix.c
  99. os-win32.c
  100. page_cache.c
  101. qapi-schema.json
  102. qdev-monitor.c
  103. qdict-test-data.txt
  104. qemu-bridge-helper.c
  105. qemu-doc.texi
  106. qemu-ga.texi
  107. qemu-img-cmds.hx
  108. qemu-img.c
  109. qemu-img.texi
  110. qemu-io-cmds.c
  111. qemu-io.c
  112. qemu-nbd.c
  113. qemu-nbd.texi
  114. qemu-option-trace.texi
  115. qemu-options-wrapper.h
  116. qemu-options.h
  117. qemu-options.hx
  118. qemu-seccomp.c
  119. qemu-tech.texi
  120. qemu.nsi
  121. qemu.sasl
  122. qmp.c
  123. qtest.c
  124. README
  125. replication.c
  126. replication.h
  127. rules.mak
  128. softmmu_template.h
  129. spice-qemu-char.c
  130. tcg-runtime.c
  131. tci.c
  132. thunk.c
  133. tpm.c
  134. trace-events
  135. translate-all.c
  136. translate-all.h
  137. translate-common.c
  138. user-exec-stub.c
  139. user-exec.c
  140. VERSION
  141. version.rc
  142. vl.c
  143. xen-common-stub.c
  144. xen-common.c
  145. xen-hvm-stub.c
  146. xen-hvm.c
  147. xen-mapcache.c