Re: [PATCH -v2] QEMU-KVM: MCE: Relay UCR MCE to guest

[Avi Kivity <avi@redhat.com>]

On 09/10/2009 12:35 PM, Andi Kleen wrote:
>>> (also, I if we can't handle guest-mode SIGBUS I think it would be nice
>>> to raise it again so the process terminates due to the SIGBUS).
>>>        
>> For SIGBUS we can not relay to guest as MCE, we can either abort or
>> reset SIGBUS to SIGDFL and re-raise it. Both are OK for me. You prefer
>> the latter one?
>>      
> I think a suitable error message and exit would be better than a plain
> signal kill. It shouldn't look like qemu crashed due to a software
> bug. Ideally a error message in a way that it can be parsed by libvirt etc.
> and reported in a suitable way.
>    

libvirt etc. can/should wait() for qemu to terminate abnormally and 
report the reason why.  However it doesn't seem there is a way to get 
extended signal information from wait(), so it looks like internal 
handling by qemu is better.


> However qemu getting killed itself is very unlikely, it doesn't
> have much memory foot print compared to the guest and other data.
> So this should be a very rare condition.
>    

(I get SIGBUS quite often running qemu from nfs and compiling a new one, 
however that's a really different use case)

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.