Unaccessible memory

[JKB]

Hello,

I'm trying to develop a OS over L4/X2 microkernel and I use Linux debian and qemu 0.13 in 64 bits mode. When I start qemu with qemu-system-x86_64 -hdc freevms.img -smp 1 -serial stdio -m 128M -k fr, my kernel boots fine. If I modify this command line with -m 384M (for example), my kernel is loaded but enter in a deadlock. I have found a bug in my code until I have tried to use the _same_ disk image under virtualbox and it works without any trouble. I runs fine on a real PC also.

I have bissected my code and qemu stops (maybe in a deadlock) when I try to access to memory :
%MEM-I-VM_ALLOC, adding $0000000000045000 - $0000000000108FFF to VM allocator
%MEM-I-VM_ALLOC, adding $000000000010B000 - $00000000003F2FFF to VM allocator
%MEM-I-VM_ALLOC, adding $000000000040C000 - $0000000000FFFFFF to VM allocator
%MEM-I-VM_ALLOC, adding $000000000100F000 - $FFFFFEFFFFFFFFFF to VM allocator
%MEM-I-ACCMAP, accepting mapping
%MEM-I-ACCMAP, virtual $FFFF000000000000 - $FFFF000000000FFF
%MEM-I-ACCMAP, physical $000000000009E000 - $000000000009EFFF

Note that qemu doesn't crash. It only stops. My virtual memory subsystem maps $FFFF000000000000 in physical memory ($9E000). And when I try to initialize this memory, qemu enters in deadlock.

A disk image to reproduce this bug is available at http://www.systella.fr/~bertrand/freevms.img.bz2

Regards,

JKB

[Michael liu (ztehypervisor)]

This is a qemu emulator problem, whould qemu stop when the memory is larger than 128M? You can try set the memory 256 to start vm.

[Thomas Huth (th-huth)]

QEMU 0.13 is pretty much outdated nowadays ... can you still reproduce this issue with the latest version of QEMU?

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]