Re: [Qemu-devel] x86_64 linux kernel doesn't boot with -icount enabled

["Cao,Bing Bu" <mars@linux.vnet.ibm.com>]

On 11/08/2011 11:52 PM, Max Filippov wrote:
> With kernel command line of 'console=ttyS0 noapic=1 panic=1' patched
> qemu boots up successfully with -icount, whereas unpatched qemu loops
> infinitely.
>
> Looks like APIC emulation issue to me.
>
I'm trying to test issue using a 2.6.38 vmlinuz image.
The image is a kernel image of a another ubuntu guest. I just copy it to 
host and use it directly.

# /usr/local/bin/qemu-system-x86_64 -enable-kvm -m 1024 -kernel 
vmlinuz-2.6.38-8-generic -append 'ro quiet noacpi=1 ' -chardev 
stdio,id=mon0 -mon chardev=mon0

The kernel can be successfully loaded and run normally until 
kernel_init(),and panic because there is no root file-system supplied.

But add -icount option:

# /usr/local/bin/qemu-system-x86_64 -enable-kvm -m 1024 -kernel 
vmlinuz-2.6.38-8-generic -append 
'root=UUID=96bc04c5-410e-482a-82bf-95b2355552d6 ro quiet noacpi=1' 
-chardev stdio,id=mon0 -mon chardev=mon0 -icount auto

The kernel can not be loaded successfully.

loop in main_loop_wait().


-- 
Best Regards,
Cao,Bing Bu