Re: [Xen-ia64-devel] Faulty protection key handling

[Jürgen Groß <juergen.gross@xxxxxxxxxxxxxxxxxxx>]

Jürgen Groß wrote:
> Tristan Gingold wrote:
>> On Wed, Apr 25, 2007 at 03:36:20PM +0200, Dietmar Hahn wrote:
>>> Hi,
>> [..]
>>> By the way, are there any thoughts about adding emulation of protection 
>>> keys 
>>> to the hypervisor? I know, whether the hypervisor nor dom0-linux are using 
>>> this but we need this stuff. I would try to write a proposal and add using 
>>> protection keys in the minios for tests. What do you think?
>> It shouldn't be that different from RID partitions: just partition PK space
>> like RID space is partitionned.  I really think the modifications are not
>> that big, unless we find a blocking issue.  I will try to think more...
> 
> Are you sure? I don't think PK space must be partitioned. Protection keys are
> an additional feature for further access limitations of pages which are
> already "protected" via RID.
> 
> One issue arises with support of protection keys: the hypervisor must be able
> to run with enabled protection keys as well (protection keys are enabled in
> %cr.dcr which is not changed in case of interruption). So we will need an own
> protection key value for the hypervisor and of course a reserved protection
> key register.

Sorry, PK is enables in %psr, of course, but there is no corresponding
%cr.dcr bit for interrupt defaults.

Juergen

-- 
Juergen Gross                             Principal Developer
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