Dear Igor, dear Kevin, dear Gerd,
Am 20.04.22 um 11:14 schrieb Igor Mammedov:
On Tue, 19 Apr 2022 09:52:42 -0400 Kevin O'Connor wrote:
On Tue, Apr 19, 2022 at 11:46:59AM +0200, Gerd Hoffmann wrote:
diff --git a/src/fw/mptable.c b/src/fw/mptable.c
index 47385cc..3a7b02f 100644
--- a/src/fw/mptable.c
+++ b/src/fw/mptable.c
If you look at the top of that file you'll see the notice:
// DO NOT ADD NEW FEATURES HERE. (See paravirt.c / biostables.c instead.)
The mptable.c file in seabios is no longer modified. If a guest OS
needs a different mptable then it will be necessary to extend qemu to
pass the desired mptable to seabios (as is done for smbios and acpi).
Maybe its time to think about removing this code? Current state of
affairs in qemu is:
# qemu-default -M help
Supported machines are:
[ ... ]
pc-i440fx-2.1 Standard PC (i440FX + PIIX, 1996)
pc-i440fx-2.0 Standard PC (i440FX + PIIX, 1996)
pc-i440fx-1.7 Standard PC (i440FX + PIIX, 1996) (deprecated)
pc-i440fx-1.6 Standard PC (i440FX + PIIX, 1996) (deprecated)
pc-i440fx-1.5 Standard PC (i440FX + PIIX, 1996) (deprecated)
pc-i440fx-1.4 Standard PC (i440FX + PIIX, 1996) (deprecated)
[ ... ]
So qemu plans to remove support for machine types 1.7 and older, this
will probably happen later this year in the 7.1 or 7.2 release.
qemu added support for passing acpi tables to the firmware in version
1.7, so the compatibility code is only used for machine types 1.6 and
older.
So in a year or so the only purpose the compatibility code will serve
is confusing people ...
I know qemu produces the acpi and smbios tables. I wasn't aware it
will currently pass in the mptable to seabios. (Nor the PIR table.)
As far as I'm aware QEMU doesn't produce legacy mptable (which was
supplemented by ACPI spec in 1996), so guest will have to parse ACPI
tales instead (MADT at minimum). I guess whoever plays with some very
legacy OS or does it for educational purpose can use old Seabios
to do that.
Along with this perhaps we also should prepare to remove code that
generates SeaBIOS own version of ACPI tables /MADT/DSDT/SSDT/SRAT/
since QEMU does this task from 1.7 and onward.
Old SeaBIOS ACPI code is likely bit-rotted at this point, we do not
exercise related code in QEMU tests.
That will also allow QEMU to drop quite a bit of legacy ABI/code
that it's kept around since this code is still present in SeaBIOS.
I'm okay with removing support from seabios. As a first step we can
change the Kconfig defaults to not produce the tables.
Please excuse my ignorance, but will it still be possible to run
alternative OS projects like KolibriOS [1] in QEMU and coreboot with
SeaBIOS payload?
Kind regards,
Paul
[1]: https://kolibrios.org/de/
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