On Wed, Jun 06, 2018 at 11:19:22AM +0200, Greg Kurz wrote: > On Wed, 6 Jun 2018 10:53:17 +1000 > David Gibson <da...@gibson.dropbear.id.au> wrote: > > > On Tue, Jun 05, 2018 at 06:46:12PM +0200, Greg Kurz wrote: > > > On Mon, 4 Jun 2018 10:53:22 +1000 > > > David Gibson <da...@gibson.dropbear.id.au> wrote: > > > > > > > On Mon, May 07, 2018 at 01:52:42PM -0300, luporl wrote: > > > > > According to PowerISA, the PIR register should be readable in > > > > > privileged > > > > > mode also, not only in hypervisor privileged mode. > > > > > > > > > > PowerISA 3.0 - 4.3.3 Processor Identification Register > > > > > > > > > > "Read access to the PIR is privileged; write access is not > > > > > provided." > > > > > > > > Yes... but a little further down it says "The PIR is a hypervisor > > > > resource". Looking at the older 2.07 ISA, it says that > > > > guest-supervisor mode reads to the PIR should be redirected to the > > > > GPIR register, which this change won't accomplish. > > > > > > > > > > Hmmm, there are two definitions for the PIR, one in Book III-S (4.3.3) > > > and one in Book III-E (5.3.3). It looks like you're referring to the > > > latter... > > > > > > [Category:Embedded.Hypervisor] > > > Read accesses to the PIR in guest supervisor state are > > > mapped to the GPIR. > > > > > > The Book III-S definition doesn't mention the GPIR. > > > > Oops, sorry. Yes the GPIR stuff is only for BookE. The statement > > about the PIR being a hypervisor resource is definitely in the BookS > > section, however (both 2.07 and 3.0). > > > > Yes it is, but IIUC, this means that the guest cannot modify it, eg, > do mtspr. Section 4.4.4 in Book III-S has a list of SPRs that seem to > indicate that mfspr doesn't require hypervisor state with the PIR.
Ah, yes, I was looking for a summary that covered that, but hadn't
found it yet.
The patch doesn't actually apply clean to the current tree any more,
due to a rename. So can you repost, and I'll apply.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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