Re: [Qemu-devel] [SeaBIOS] KVM call agenda for 2013-05-28

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, May 30, 2013 at 09:57:10AM -0700, Jordan Justen wrote:
> On Thu, May 30, 2013 at 9:41 AM, Laszlo Ersek <lersek@redhat.com> wrote:
> > On 05/30/13 18:20, Jordan Justen wrote:
> >> I think ACPI table generation lives in firmware on real products,
> >> because on real products the firmware is the point that best
> >> understands the actual hardware layout for the machine. In qemu, I
> >> would say that qemu best knows the hardware layout, given that the
> >> firmware is generally a slightly separate project from qemu.
> >>
> >> I don't think adding a coreboot layer into the picture helps, if it
> >> brings along the coreboot payload boot interface as a requirement.
> >>
> >> Then again, I don't really understand how firmware could be swapped
> >> out in this case. What would -bios do? How would the coreboot ACPI
> >> shim layer be specified to qemu?
> >
> > I guess -bios would load coreboot. Coreboot would siphon the data
> > necessary for ACPI table building through the current (same) fw_cfg
> > bottleneck, build the tables, load the boot firmware (SeaBIOS or OVMF or
> > something else -- not sure how to configure that), and pass down the
> > tables to the firmware (through a now unspecified interface -- perhaps
> > the tables could even be installed at this point). This could introduce
> > another interface (fw_cfg+something rather than just fw_cfg), but ACPI
> > table preparation would be concentrated in one project.
> >
> > I guess.
> 
> For reference, I believe that both Xen and virtualbox build ACPI table
> in the VMM rather than firmware. They both dump the tables into the
> 0xe000 segment (yuck) where firmware finds and publishes it to the OS.
> I think fw-cfg would be a reasonable alternative to this for
> communicating the tables.
> 
> -Jordan

Want to review/ack the patches I sent? That's exactly what they do.

-- 
MST