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[Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs
From: |
Avi Kivity |
Subject: |
[Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs |
Date: |
Sun, 30 May 2010 12:09:45 +0300 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 |
On 05/28/2010 09:21 PM, Markus Armbruster wrote:
<snip, agreed>
Summary of the host / guest split:
-drive options host or guest?
bus, unit, if, index, addr guest, already covered by qdev
cyls, heads, secs, trans guest, new qdev properties
(but defaults depend on image)
media guest
snapshot, file, cache, aio, format host, blockdev_add options
We expose some of the cache property to the guest. IMO we need the
cache property to be both guest and host, with qemu bridging the
impedance mismatch if needed.
rerror, werror host, guest drivers will reject
values they don't support
Did you mean 'block format drivers will reject'?
serial guest, new qdev properties
readonly both host& guest, qdev will refuse
to connect readonly host to read/
write guest
QMP command docs:
blockdev_add
------------
Add host block device.
Arguments:
- "id": the host block device's ID, must be unique (json-string)
Unique in which namespace? A global ID namespace if fine.
- "file": the disk image file to use (json-string, optional)
- "format": disk format (json-string, optional)
- Possible values: "raw", "qcow2", ...
Need some way to list supported formats.
- "aio": host AIO (json-string, optional)
- Possible values: "threads" (default), "native"
Need some way to list supported options.
- "cache": host cache usage (json-string, optional)
- Possible values: "writethrough" (default), "writeback", "unsafe",
"none"
...
- "readonly": open image read-only (json-bool, optional, default false)
- "rerror": what to do on read error (json-string, optional)
- Possible values: "report" (default), "ignore", "stop"
...
- "werror": what to do on write error (json-string, optional)
- Possible values: "enospc" (default), "report", "ignore", "stop"
...
- "snapshot": enable snapshot (json-bool, optional, default false)
An alternative to the "Need some way to list *" is to provide another
query capability, akin to KVM_CAP_..., but I think listing is superior.
Example:
-> { "execute": "blockdev_add",
"arguments": { "format": "raw", "id": "blk1",
"file": "fedora.img" } }
<- { "return": {} }
Notes:
(1) If argument "file" is missing, all other optional arguments must be
missing as well. This defines a block device with no media
inserted.
(2) It's possible to list supported disk formats by running QEMU with
arguments "-blockdev_add \?".
Ok, so there's a partial answer here.
blockdev_change
---------------
Change host block device media.
Arguments are exactly like blockdev_add.
Notes:
(1) If argument "file" is missing, all other optional arguments must be
missing as well. This ejects the media without inserting a new one.
Maybe we want an explicit blockdev_eject instead, not sure.
--
error compiling committee.c: too many arguments to function
- [Qemu-devel] RFC: blockdev_add & friends, brief rationale, QMP docs, Markus Armbruster, 2010/05/28
- [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Kevin Wolf, 2010/05/28
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Anthony Liguori, 2010/05/28
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Luiz Capitulino, 2010/05/28
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Avi Kivity, 2010/05/30
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Markus Armbruster, 2010/05/31
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Luiz Capitulino, 2010/05/31
- Re: [Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs, Kevin Wolf, 2010/05/31
[Qemu-devel] Re: RFC: blockdev_add & friends, brief rationale, QMP docs,
Avi Kivity <=