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

2014-05-31 Thread 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

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

2014-05-31 Thread Stefan Weil 
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).
> 
> Paolo
> 


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.

Stefan

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

2014-05-31 Thread 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).


Paolo

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

2014-05-31 Thread Adam Baxter 
Sorry. FASM 1.66 (included as a FreeDOS package) crashes as described, but
FASM 1.71.21 works as expected.

--Adam