[SeaBIOS] KVM cpu limitations

[Kevin O'Connor]

On Tue, Aug 09, 2011 at 02:32:02PM -0400, John Paul Walters wrote:
> I've enabled debugging in seabios (#define DEBUG_BIOS) and get the
> output below.  Note that with the help of folks in the KVM irc
> channel I'm able to start a 254 core instance using the KVM tool, so
> the problem seems to be limited to qemu/seabios.
[...]
> jwalters at uv /tmp/qemu_test_jp $ /opt/qemu.git/bin/qemu-system-x86_64 -smp 84 -drive file=big_image_2.qcow2,if=virtio -m 8388
> Found 84 cpu(s) max supported 84 cpu(s)
> MP table addr=0x000fd4b0 MPC table addr=0x000fd4c0 size=1892
> SMBIOS ptr=0x000fd490 table=0xdffff030
> ACPI tables: RSDP=0x000fd460 RSDT=0xdfffa5c0
[...]
> WARNING - Unable to allocate resource at init_virtio_blk:107!
> WARNING - Unable to allocate resource at init_atadrive:740!

You're hitting a weird interaction with the mptable - its allocation
just barely fits, and since it takes up all the ram in the f-segment
it causes other allocations to fail (which are needed to hold info on
the boot drive).

This should no longer be an issue in the latest SeaBIOS from git.
Alternatively, if you increase the number of CPUs, you should see the
machine boot becuase only the mptable allocation will fail.

-Kevin