[SeaBIOS] [PATCH 2/2] accept MADT over fw_cfg
Michael S. Tsirkin
mst at redhat.com
Sun Mar 24 14:06:14 CET 2013
On Fri, Mar 22, 2013 at 08:02:21PM +0100, Paolo Bonzini wrote:
> Il 21/03/2013 14:12, Michael S. Tsirkin ha scritto:
> > On Thu, Mar 21, 2013 at 01:04:35PM +0000, David Woodhouse wrote:
> >> On Thu, 2013-03-21 at 13:56 +0100, Laszlo Ersek wrote:
> >>> - for an earlier qemu, the option must be set,
> >>> - for a later qemu the option must be clear &&
> >>> (no -acpitable switch must be specified on the qemu cmldine ||
> >>> one -acpitable switch must load a MADT)
> >> Hm, that sounds like it won't be possible to build one version of
> >> SeaBIOS that works for *both* old and new qemu. That doesn't seem like a
> >> great idea. I'd prefer something like:
> >> - If Qemu provides the 'core' ACPI tables (i.e. not just SSDT) then
> >> SeaBIOS uses them.
> >> - Otherwise, it makes its own.
> >> --
> >> dwmw2
> > It might simplify life for someone bisecting qemu
> > as you don't need to rebuild seabios after each
> > bisect but is this really a common workflow?
> It would help me working on RHEL's qemu-kvm, which I often do on a
> Fedora box.
> The bios.bin in the RHEL qemu-kvm tree is obsolete (like Gerd showed for
> Fedora, RHEL's bios.bin comes from a separate package), and using
> whatever happens to be in /usr or in my local SeaBIOS clone is the
> simplest thing to do. I'd like this not to break.
Sure, but be warned that the seabios copy of ACPI tables will bitrot
with time, it will only be used for old qemu binaries. We might not be
able to keep it alive for the full multi-year RHEL lifecycle.
> > Anyway, I am not against such runtime flags.
> > If we add to this an option to build a minimal BIOS
> > that only works with the new QEMU, do we have a deal?
> > Then the plan is to make progress and apply patches step by step without
> > deciding on the detection interface first.
> > Before QEMU is switched to the new configuration,
> > we'll add the runtime thing for the benefit of developers
> > that bisect.
> > Makes sense?
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