Il 13/09/2012 22:12, Jason Baron ha scritto:
Subject: [PATCH 0/9] q35 seabios support take #1
Hi,
Seabios bits for q35 support, I'm posting the qemu changes separately. The patches require '-M pc_q35' and -L 'seabios dir with q35 changes' on the qemu command line. Hopefully, we can make it the default for x86 at some future point when we feel comfortable with it.
The main question, IMHO, is how to proceed for supporting both PIIX4 and q35. The two extreme possibilities are:
- use a single binary for everything
- use two binaries for everything
Right now, you do a mix of the two, where you have two DSDTs and one binary. Furthermore, PIIX4 is still a "preferred" chipset in that its DSDT is embedded in SeaBIOS and q35's isn't.
With more than one chipset being supported, and with the desire to support OVMF/UEFI as an alternative firmware, I think it makes sense to move QEMU towards a model more similar to CoreBoot's, where QEMU itself makes the default ACPI tables and passes them to SeaBIOS or OVMF via fw_cfg.
So my favorite choice is to move the DSDT to fw_cfg, and keep a single binary for everything else. I don't really care whether the DSDT sources live in the SeaBIOS or QEMU repository, though the former makes more sense until all things ACPI are done in QEMU.
Paolo
On Fri, Sep 14, 2012 at 09:23:46AM +0200, Paolo Bonzini wrote:
Il 13/09/2012 22:12, Jason Baron ha scritto:
Subject: [PATCH 0/9] q35 seabios support take #1
Hi,
Seabios bits for q35 support, I'm posting the qemu changes separately. The patches require '-M pc_q35' and -L 'seabios dir with q35 changes' on the qemu command line. Hopefully, we can make it the default for x86 at some future point when we feel comfortable with it.
The main question, IMHO, is how to proceed for supporting both PIIX4 and q35. The two extreme possibilities are:
use a single binary for everything
use two binaries for everything
Right now, you do a mix of the two, where you have two DSDTs and one binary. Furthermore, PIIX4 is still a "preferred" chipset in that its DSDT is embedded in SeaBIOS and q35's isn't.
With more than one chipset being supported, and with the desire to support OVMF/UEFI as an alternative firmware, I think it makes sense to move QEMU towards a model more similar to CoreBoot's, where QEMU itself makes the default ACPI tables and passes them to SeaBIOS or OVMF via fw_cfg.
So my favorite choice is to move the DSDT to fw_cfg, and keep a single binary for everything else. I don't really care whether the DSDT sources live in the SeaBIOS or QEMU repository, though the former makes more sense until all things ACPI are done in QEMU.
Yes agreed, especially since I needlessly wasting ram on q35 with the piix acpi table.
In terms of implementation then, qemu would basically advertise a single dsdt table (based on the -M) using fw_cfg, and then seabios would pick up the correct one. Is that the right way to think about it?
Thanks,
-Jason
Il 14/09/2012 16:35, Jason Baron ha scritto:
In terms of implementation then, qemu would basically advertise a single dsdt table (based on the -M) using fw_cfg, and then seabios would pick up the correct one. Is that the right way to think about it?
That's what I like, Gerd suggested on qemu-devel two seabios binaries.
Paolo
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Jason Baron -
Paolo Bonzini