Re: [PATCH 23/25] [PATCH] paravirt hooks for arch initialization

Jeremy Fitzhardinge escreveu:

Glauber de Oliveira Costa wrote:

quoted

I think the idea you gave me earlier of using probe_kernel_address could
work. Xen/lguest/put_yours_here that won't use an ebda would then have
to unmap the page, to make sure a read would fault.

Hm, the memory might be mapped anyway, but we could make sure its all
zero.  discover_ebda should be able to deal with that OK.

    J

Indeed, as the EBDA_ADDR_POINTER is not aligned, this may work even better.

It seems to me safe to assume that if we read zero on that line:

ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);

We could just do ebda_size = 0 and go home happy, skipping the rest of 
the process.

Andi, are you okay with it ?