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@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