[libvirt] [PATCH 4/4] qemu: Add support for setting the TSEG size

[Martin Kletzander]

On Thu, Jun 07, 2018 at 10:14:38PM +0200, Laszlo Ersek wrote:
>On 06/07/18 21:58, Ján Tomko wrote:
>
>> Does a size of 0 MiB make sense? It's divisible by 1 MiB.
>
>"-global mch.extended-tseg-mbytes=0" makes QEMU behave as if it lacked
>the extended TSEG feature; the guest will believe that only the standard
>1 / 2 / 8 MB TSEG sizes are available, and pick one of those.
>
>Technically, in QEMU the extended TSEG feature is disabled for older
>machine types by setting "mch.extended-tseg-mbytes" to zero:
>
>[include/hw/i386/pc.h]
>
>#define PC_COMPAT_2_9 \
>    HW_COMPAT_2_9 \
>    {\
>        .driver   = "mch",\
>        .property = "extended-tseg-mbytes",\
>        .value    = stringify(0),\
>    },\
>
>I'm unsure whether this -- i.e., disabling the feature -- is useful to
>expose through the domain config. Probably not.
>

I wouldn't want to disable that option now in a way that we won't be able to fix
later.  So from my point of view it makes sense.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: Digital signature
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20180607/fcfb4b75/attachment-0001.sig>