diff options
author | Peter Maydell <peter.maydell@linaro.org> | 2019-10-25 14:59:53 +0100 |
---|---|---|
committer | Peter Maydell <peter.maydell@linaro.org> | 2019-10-25 14:59:53 +0100 |
commit | 03bf012e523ecdf047ac56b2057950247256064d (patch) | |
tree | 6e1b06a3c71cfb191bc2aabc8a79d436c9d05d72 /qemu-options.hx | |
parent | bad76ac319556dab2497429d473b49a237672e1c (diff) | |
parent | 5e9785505210e2477e590e61b1ab100d0ec22b01 (diff) |
Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging
Block layer patches:
- qcow2: Fix data corruption bug that is triggered in partial cluster
allocation with default options
- qapi: add support for blkreplay driver
- doc: Describe missing generic -blockdev options
- iotests: Fix 118 when run as root
- Minor code cleanups
# gpg: Signature made Fri 25 Oct 2019 14:19:04 BST
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6
* remotes/kevin/tags/for-upstream:
qcow2: Fix corruption bug in qcow2_detect_metadata_preallocation()
coroutine: Add qemu_co_mutex_assert_locked()
doc: Describe missing generic -blockdev options
block/backup: drop dead code from backup_job_create
blockdev: Use error_report() in hmp_commit()
iotests: Skip read-only cases in 118 when run as root
qapi: add support for blkreplay driver
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'qemu-options.hx')
-rw-r--r-- | qemu-options.hx | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index 88b05599b1..b95bf9fbed 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -864,7 +864,8 @@ ETEXI DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" " [,cache.direct=on|off][,cache.no-flush=on|off]\n" - " [,read-only=on|off][,detect-zeroes=on|off|unmap]\n" + " [,read-only=on|off][,auto-read-only=on|off]\n" + " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" " [,driver specific parameters...]\n" " configure a block backend\n", QEMU_ARCH_ALL) STEXI @@ -900,6 +901,25 @@ name is not intended to be predictable and changes between QEMU invocations. For the top level, an explicit node name must be specified. @item read-only Open the node read-only. Guest write attempts will fail. + +Note that some block drivers support only read-only access, either generally or +in certain configurations. In this case, the default value +@option{read-only=off} does not work and the option must be specified +explicitly. +@item auto-read-only +If @option{auto-read-only=on} is set, QEMU may fall back to read-only usage +even when @option{read-only=off} is requested, or even switch between modes as +needed, e.g. depending on whether the image file is writable or whether a +writing user is attached to the node. +@item force-share +Override the image locking system of QEMU by forcing the node to utilize +weaker shared access for permissions where it would normally request exclusive +access. When there is the potential for multiple instances to have the same +file open (whether this invocation of QEMU is the first or the second +instance), both instances must permit shared access for the second instance to +succeed at opening the file. + +Enabling @option{force-share=on} requires @option{read-only=on}. @item cache.direct The host page cache can be avoided with @option{cache.direct=on}. This will attempt to do disk IO directly to the guest's memory. QEMU may still perform an |