cirrus: add option to disable blitter

Ok, we have this beast in the cirrus code which is not used at all by
modern guests, except when you try to find security holes in qemu.  So,
add an option to disable blitter altogether.  Guests released within
the last ten years should not show any rendering issues if you turn off
blitter support.

There are no known bugs in the cirrus blitter code.  But in the past we
hoped a few times already that we've finally nailed the last issue.  So
having some easy way to mitigate in case yet another blitter issue shows
up certainly makes me sleep a bit better at night.

For completeness:  The by far better way to mitigate is to switch away
from cirrus and use stdvga instead.  Or something more modern like
virtio-vga in case your guest has support for it.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 1489494540-15745-1-git-send-email-kraxel@redhat.com
1 file changed
tree: fcec479fb38aeeb4b6f13f0528feccd973736965
  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. .dir-locals.el
  41. .exrc
  42. .gitignore
  43. .gitmodules
  44. .mailmap
  45. .shippable.yml
  46. .travis.yml
  47. accel.c
  48. arch_init.c
  49. atomic_template.h
  50. balloon.c
  51. block.c
  52. blockdev-nbd.c
  53. blockdev.c
  54. blockjob.c
  55. bootdevice.c
  56. bt-host.c
  57. bt-vhci.c
  58. Changelog
  59. CODING_STYLE
  60. configure
  61. COPYING
  62. COPYING.LIB
  63. cpu-exec-common.c
  64. cpu-exec.c
  65. cpus-common.c
  66. cpus.c
  67. cputlb.c
  68. device-hotplug.c
  69. device_tree.c
  70. disas.c
  71. dma-helpers.c
  72. dump.c
  73. exec.c
  74. gdbstub.c
  75. HACKING
  76. hax-stub.c
  77. hmp-commands-info.hx
  78. hmp-commands.hx
  79. hmp.c
  80. hmp.h
  81. ioport.c
  82. iothread.c
  83. kvm-all.c
  84. kvm-stub.c
  85. LICENSE
  86. MAINTAINERS
  87. Makefile
  88. Makefile.objs
  89. Makefile.target
  90. memory.c
  91. memory_ldst.inc.c
  92. memory_mapping.c
  93. module-common.c
  94. monitor.c
  95. numa.c
  96. os-posix.c
  97. os-win32.c
  98. page_cache.c
  99. qapi-schema.json
  100. qdev-monitor.c
  101. qdict-test-data.txt
  102. qemu-bridge-helper.c
  103. qemu-doc.texi
  104. qemu-ga.texi
  105. qemu-img-cmds.hx
  106. qemu-img.c
  107. qemu-img.texi
  108. qemu-io-cmds.c
  109. qemu-io.c
  110. qemu-nbd.c
  111. qemu-nbd.texi
  112. qemu-option-trace.texi
  113. qemu-options-wrapper.h
  114. qemu-options.h
  115. qemu-options.hx
  116. qemu-seccomp.c
  117. qemu-tech.texi
  118. qemu.nsi
  119. qemu.sasl
  120. qmp.c
  121. qtest.c
  122. README
  123. replication.c
  124. replication.h
  125. rules.mak
  126. softmmu_template.h
  127. spice-qemu-char.c
  128. tcg-runtime.c
  129. tci.c
  130. thunk.c
  131. tpm.c
  132. trace-events
  133. translate-all.c
  134. translate-all.h
  135. translate-common.c
  136. user-exec-stub.c
  137. user-exec.c
  138. VERSION
  139. version.rc
  140. vl.c
  141. xen-common-stub.c
  142. xen-common.c
  143. xen-hvm-stub.c
  144. xen-hvm.c
  145. xen-mapcache.c