On Thu, 2006-08-31 at 08:07 -0400, Jimi Xenidis wrote: > > Hollis, ASAICT the only way Amos could have gotten here (and passed > the BUG() in pfn2mfn()) is if one of the user_copy routines tried to > access a PFN_TYPE_REMOTE or PFN_TYPE_IO, that paddr is not an IO type > so the question I have for you is: > Is it possible for Xen (on behalf of a privileged domain) use a > user_copy routine to access another domains memory?
No. Because copy_*_guest() require a xencomm_desc structure to do anything, they can only copy into areas of memory the domain expects. However, if we need that functionality, we can create a parallel API to do this. x86 does that right now with copy_*_user() -- that API only exists in x86-specific code, and it directly accesses the "user" virtual address.  If we go with IA64's proposed "inline" extension to the xencomm stuff, this isn't strictly true and I think we could copy to physically contiguous areas that way. -- Hollis Blanchard IBM Linux Technology Center _______________________________________________ Xen-ppc-devel mailing list Xenemail@example.com http://lists.xensource.com/xen-ppc-devel