On 23.09.2016 18:06, Kevin Wolf wrote: > This adds documentation for the -blockdev options that apply to all > nodes independent of the block driver used. > > All options that are shared by -blockdev and -drive are now explained in > the section for -blockdev. The documentation of -drive mentions that all > -blockdev options are accepted as well. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > Reviewed-by: Eric Blake <ebl...@redhat.com> > --- > qemu-options.hx | 98 > ++++++++++++++++++++++++++++++++++++++++----------------- > 1 file changed, 69 insertions(+), 29 deletions(-) > > diff --git a/qemu-options.hx b/qemu-options.hx > index 542c483..8766589 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -523,6 +523,43 @@ STEXI > @findex -blockdev > > Define a new block driver node. > + > +@table @option > +@item Valid options for any block driver node: > + > +@table @code > +@item driver > +Specifies the block driver to use for the given node. > +@item node-name > +This defines the name of the block driver node by which it will be referenced > +later. The name must be unique, i.e. it must not match the name of a > different > +block driver node, or (if you use @option{-drive} as well) the ID of a drive.
Could use a mention of the default behavior, but since you didn't do that anywhere else, not doing so is fine, too. > +@item read-only > +Open the node read-only. Guest write attempts will fail. > +@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 > +internal copy of the data. > +@item cache.no-flush > +In case you don't care about data integrity over host failures, use > +@option{cache.no-flush=on}. This option tells QEMU that it never needs to > write Just text movement, but that doesn't mean we can improve it: While it's a matter of test whether to use contractions in official documentations (some do not (e.g. me), others do; and the state of the qemu man page reflects this well), I'd definitely rather not use an imperative here. If people do not care about this, they *may contemplate* using this option. But we should not tell them to. > +any data to the disk but can instead keep things in cache. If anything goes > +wrong, like your host losing power, the disk storage getting disconnected > +accidentally, etc. your image will most probably be rendered unusable. Especially since losing integrity of your data is something different than losing access to your data entirely. > +@item discard=@var{discard} > +@var{discard} is one of "ignore" (or "off") or "unmap" (or "on") and controls > +whether @dfn{discard} (also known as @dfn{trim} or @dfn{unmap}) requests are > +ignored or passed to the filesystem. Some machine types may not support Again, just text movement, but the double whitespace after the period here is inconsistent with the rest. > +discard requests. > +@item detect-zeroes=@var{detect-zeroes} > +@var{detect-zeroes} is "off", "on" or "unmap" and enables the automatic > +conversion of plain zero writes by the OS to driver specific optimized > +zero write commands. You may even choose "unmap" if @var{discard} is set > +to "unmap" to allow a zero write to be converted to an UNMAP operation. Once more, just text movement, but to be consistent, I'd prefer @dfn{unmap} here like above. Max > +@end table > + > +@end table > + > ETEXI > > DEF("drive", HAS_ARG, QEMU_OPTION_drive,
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