Re: [Qemu-devel] qemu crash running FASM/FreeDOS

[Michael Tokarev]

31.05.2014 12:22, Stefan Weil wrote:
> Am 31.05.2014 09:57, schrieb Paolo Bonzini:
>> Il 31/05/2014 09:50, Adam Baxter ha scritto:
>>> Sorry. FASM 1.66 (included as a FreeDOS package) crashes as described,
>>> but FASM 1.71.21 works as expected.
>>
>> Yeah, I was about to reply that if a userspace program crashes both TCG
>> and KVM, it's more likely to be a bug in that program (or at worst
>> SeaBIOS, but in your case the output pointed at the program).
> 
> A userspace program should never crash QEMU system emulation, should it?
> Overwise this would allow Denial-of-service by any user in the virtual
> machine.

If the guest kernel is correct.

In this case this is FreeDOS, which allows any instructions to be run
by "userspace" programs.  And when such a bad/invalid instruction is
run, real hw will either reboot or lock up, -- this is much more
severe DoS condition :)

Thanks,

/mjt