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

[Jürgen Groß <juergen.gross@xxxxxxxxxxxxxxxxxxx>]

Tristan Gingold wrote:
> On Thu, Apr 26, 2007 at 09:08:21PM +0200, Tristan Gingold wrote:
>> On Thu, Apr 26, 2007 at 08:31:11AM +0200, Jürgen Groß wrote:
>>> Tristan Gingold wrote:
>>> For PV domains this should be easy: 15 PKRs should be enough for the DomU.
>>> For HVM the PKRs must be virtualized completely.
>> I think this is the easiest solution, although it breaks the architecture
>> requirements.
> If you reserve a PKR for the hypervisor, you must reserve a value too.  So
> the PK space must still be reduced ;-)

For PV this is not completely true. If an OS uses PKRs, it has the same
problem as the hypervisor: one PKR with a specific value must always be loaded
for interrupt handling. I would see no problem to use the same PKR and PK
value as the hypervisor (PKR 0 with PK value 0, rwx allowed).
This would eliminate the restriction to 15 PKRs as well.

Juergen

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Juergen Gross                             Principal Developer
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