Re: [libvirt] [PATCH] Don't parse/format vram attribute for cirrus video
On Thu, Jun 20, 2019 at 14:51:12 -0500, Jonathon Jongsma wrote:
Since the cirrus vga memory size isn't configurable, we can
ignore any
'vram' attribute when parsing a domain definition. However, when no
value is specified, it ends up getting set to a default value of 16MB.
This 16MB value is not used anywhere (for example, it is not passed as
an argument to qemu), but is displayed in the XML definition. So by
changing this default value to 0, it will also be omitted from the XML
definition of the domain.
Fixes: rhbz#1447831
Please always use the full link so that it's clickable and users don't
have to figure out what 'rhbz' is.
Signed-off-by: Jonathon Jongsma <jjongsma(a)redhat.com>
---
This is an attempt to apply the fix suggested by Gerd at
https://bugzilla.redhat.com/show_bug.cgi?id=1447831#c2. I'm not
totally confident that this is the right approach, since I'm
relatively new to the code. Another approach might be to simply close
the bug as NOTABUG since it doesn't seem that having this unused
attribute in the domain definition has any significant drawbacks.
We certainly should not set any default if it's not used. There's not
much else we can do though as we did put a default into the
configuration. Doing any validation would mean that any VM which had the
default errorneously configured in the XML would fail to start.
Whether it's worth clearing the default or not I'm not so certain but I
don't think it should hurt.
You definitely should fix the docs though:
https://libvirt.org/formatdomain.html#elementsVideo
As it says 'For a guest of type "kvm", the default video is: type with
value "cirrus", vram with value "16384" and heads with value
"1".'
(see docs/formatdomain.html.in )
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