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

[Jürgen Groß <juergen.gross@xxxxxxxxxxxxxxxxxxx>]

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.
For PV domains this should be easy: 15 PKRs should be enough for the DomU.
For HVM the PKRs must be virtualized completely.

Juergen

-- 
Juergen Gross                             Principal Developer
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