Re: [libvirt] OVMF exposure in libvirt
On 14.07.2014 16:12, Paolo Bonzini wrote:
Il 14/07/2014 11:27, Daniel P. Berrange ha scritto:
> -drive file=img_1,if=pflash,format=raw,readonly \
> -drive file=img_2,if=pflash,format=raw
It's safer to add ",unit=0" and ",unit=1" too.
> We already use <loader/> for specifying alternative BIOS blobs for
> the QEMU -bios arg. Since you say this obsoletes the -bios arg, I
> think it makes sense to use <loader/> for the read-only firmware
> image.
It obsoletes the -bios argument, but it is not the same thing:
1) on some machines you can use "-drive if=pflash" for the nvram, but
not for the firmware
And how should the FW cmd line look like then?
2) on some older versions of QEMU, "-drive if=pflash" will work only on
TCG or will not work at all so you cannot blindly replace it.
Whoa. How to detect this? I mean, how do detect both?
What about:
<loader readonly='on|off' type='rom|flash'>...</loader>
<nvram>...</nvram>
where the mapping from <nvram> to -drive if=flash is partly
machine-dependent. On x86, for example, <nvram> adds the ",unit=1"
sub-option and fails if the <loader> element is absent; it also fails if
<loader> has type='rom'.
Makes sense.
> For the variable storage, I'd probably suggest <nvram/>
as the
> element name, since IIUC that's a fairly commonly used term for
> this concept.
I like this.
> Additionally it would be great if we'd be able to
> generate an empty nvram for a guest if the user doesn't specify it.
I'm not big fan of this. Pre-creating storage is something that should
be done by mgmt applications (migration with non-shared storage is
something different).
Laszlo has OVMF patches to "auto-format" an all-zero nvram file.
Great. Do they work automagically or does libvirt need to enable the
formatting somehow (e.g. monitor command, cmd line argument, ...)?
Paolo