Re: [Qemu-devel] [Patch] Support translating Guest physical address to Host virtual address.

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 02/02/2010 10:04 PM, Zheng, Jiajia wrote:
> Hi,
> Any futher comments for this patch so that we can modify?
>    

Unfortunately, I see no way to modify this feature so that it would be 
acceptable to upstream.  I think you're going to have to carry this 
patch for your own debugging.

The problem is, the approach you're taking to testing is extremely 
racy.  Even just with the p2v command, the mapping within qemu that 
translates guest physical to host virtual is not stable over any given 
period of time.  By the time the monitor prints out the virtual mapping 
of a host page, it's already potentially wrong.

Likewise, the virtual->physical mapping within the host is also not 
stable so using that virtual address to lookup a physical address in the 
kernel is inherently racy.

If you want to integrate MCE testing into qemu using the host to inject 
MCEs, you'll need to figure out a way to do it that allows the whole 
thing to be done without potentially killing the wrong process or 
injecting it to within the wrong address within qemu.  I suspect that's 
going to be very difficult to achieve.

Regards,

Anthony Liguori