Re: accessing domain's page contents from hypervisor

[Pradheep K E <pradheep.ke@gmail.com>]

I have seen a very similar situation too. When I tried to dereference
a domain's page from Xen, after mapping it to a virtual address is
Xen, my machine also booted. I think,  this means some locked data
structure is being accessed. Anyone, any ideas?






---------------------------------------------------------------------------------------------------
> Hi,

I was trying to read the contents of a domain's L1 page table page
from hypervisor.
The system reboots whenever I dereference the contents of a page.
I use the map_domain_mem and unmap_domain_mem functions before and
after I dereference it.
Any suggestions on the possible reasons would be really helpful.

Thanks,
Sai


/*----------------------code---start------------------------------*/
    unsigned long * pg;
    int i;
    list_for_each_entry(page, &d->page_list, list)
    {
        if ( (page->u.inuse.type_info & PGT_type_mask) == PGT_l1_page_table){
       
            pg = (unsigned long *) map_domain_mem(domain_id);
             for(i=0; i<1024; i++) {
                if( ( pg != NULL) &&  (pg[i] & 0x00000041) )
                count++;
              }
         }
         unmap_domain_mem(pg);
     }
/*----------------------code---end------------------------------*/