Re: [PATCH 11/20] xen: use XSM instead of IS_PRIV where duplicated

[Daniel De Graaf <dgdegra@tycho.nsa.gov>]

On 09/11/2012 05:05 AM, Ian Campbell wrote:
> On Tue, 2012-09-11 at 08:29 +0100, Jan Beulich wrote:
>>>  * do_console_io has changed to IS_PRIV from an explicit domid==0
>>
>> I see a point in actually limiting this to Dom0 - that's the only
>> domain that can't possibly have a virtual console. But I'm not
>> really opposed to changing this.
> 
> On a debug and/or verbose build of the hypervisor any domain can log
> here, and pvops Linux with earlyprintk=xen and/or xen_raw_printk will do
> so - it's quite useful for debugging early start of day issues in guest
> kernels. Although I suppose we can always comment out the check locally
> when doing such debugging.

I did keep the #ifdef VERBOSE around that IS_PRIV check, although it's
not noted in the commit message. I also take advantage of earlyprintk=xen
for debugging and for minios output.
 
> It occurs to me now that perhaps this should be handled more like the
> HVM port e9 stuff (i.e. with rate limiting etc) anyway.
> 
> Ian.
> 

I also have a patch for debugging that prepends "(domid) " to the console
output to help sorting out the serial log output when many domains are
using it (which is quite helpful during bootup). Combined with rate
limiting, this should make domU serial output useful in production builds.

-- 
Daniel De Graaf
National Security Agency