[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Insufficiently documented deprecated command arguments
From: |
Markus Armbruster |
Subject: |
Re: Insufficiently documented deprecated command arguments |
Date: |
Wed, 11 Dec 2019 17:30:04 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) |
Peter Krempa <address@hidden> writes:
> On Wed, Dec 11, 2019 at 12:32:10 +0000, Daniel Berrange wrote:
>> On Wed, Dec 11, 2019 at 01:24:17PM +0100, Kevin Wolf wrote:
>> > Am 11.12.2019 um 11:51 hat Peter Krempa geschrieben:
>> > > On Wed, Dec 11, 2019 at 11:14:39 +0100, Kevin Wolf wrote:
>
> [...]
>
>> > > Well, in some specific cases we could detect the node names
>> > > auto-assigned by qemu and use them instead of paths, but in my opinion
>> > > it's not worth the effort and extra code.
>> >
>> > Well, the question is what to do on the QEMU side then. Deprecation
>> > should mean that we have a plan for removing the feature. If we're
>> > planning to keep the feature indefinitely because libvirt needs it, we
>> > might want to consider removing the deprecation notice.
>>
>> Ideally libvirt would stop using -drive entirely, as I hate the idea of
>> having to keep this around indefinitely in libvirt too. This needs QEMU
>> to close the last gaps wrt SD cards
>
> Yes and also give us guidance how to convert it. Looking at the code
> didn't help. There's a plethora of controllers and options to configure
> without clear indication what is default behaviour expected.
Similar situation as for if=pflash. That one we addressed just for
"tier 1" machine types: i386 pc-*, arm virt-*.
Would addressing if=sd just for these machines suffice?
Addressing if=pflash and if=sd for all machines looks is beyond my
capacity.
For a more detailed analysis, see my "Review of onboard block device
configuration with -drive", Message-ID:
<address@hidden>. Relevant parts:
The interface types are:
[...]
* if=pflash
Many machines have onboard pflash devices. They recognize
bus=0,unit=U where 0 <= U < number of such onboard devices. ARM
machine sbsa-ref, virt, i386 machines pc*, isapc, xenfv, Risc-V
machine virt provide machine properties for connecting backends to
their onboard pflash devices. For the other machines, -drive is still
the only way to connect backends.
PPC machines pseries* create spapr-nvram devices instead. It can be
created with -device instead.
SPARC machine niagara creates a memory region instead *boggle*.
-drive is the only way to configure that.
Other machines create the onboard pflash device only when the
corresponing drive is present. Since pflash devices are not
pluggable, -drive is the only way to create them.
[...]
* if=sd
Many machines have onboard sd-card devices. They recognize
bus=0,unit=U where 0 <= U < number of such onboard devices. -drive is
the only way to connect backends.
[...]
Summary
[...]
* if=pflash, if=mtd and if=sd are blocked by the "no way to connect
backends to onboard devices" issue, and the "no way to create the
device" issue. We solved them for if=pflash with some boards. Many
more remain.
> Trying to convert it blindly would end up worse than just ditching
> support for sdcards altogehter.
Tempting, isn't it?