Re: Dom0 PAE panic when starting xend

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

Christoph Egger wrote:
> PFN 55555 is obviously bogus. It gets used as poison in 
machine-to-phys and
> phys-to-machine tables in some cases. domain->interface should have been
> mapped at setup time by a call to xc_map_foreign_range() in
> xenstored_domain.c:do_introduce(). An attempt to demand-map the interface
> page probably means something went wrong earlier.

Hmm, if this problem happens while there is no domain running (except 
dom0), I am not sure that the xc_map_foreign_range() code is at fault.

I am more inclined to say that the mmap() code used to map the initial 
xen_start_info of dom0 (through /dev/xsd_kva) is doing something wrong 
(see dom0_init() with the call to xenbus_map()). This part is skipped 
when you start xenstored with -D, which looks plausible to me.

However, I can't manage to reproduce that issue with dom0 PAE and Xen3.3.

Reading xsd_kva code around its mmap routine (xenevtmmap() in 
arch/xen/xen/xenevt.c), it is using x86_btop which casts away to 
unsigned long, which could be wrong with PAE (paddr_t being unsigned 
long long).

Could you give [1] a try (ugly, but I'd like to check that first)

Thanks,

[1] http://www.netbsd.org/~jym/xenevt.c.diff

--
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost