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Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield,
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches |
Date: |
Wed, 15 Jun 2016 14:17:57 +1000 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Mon, Jun 13, 2016 at 06:08:30PM -0500, address@hidden wrote:
> We've used older versions of QEMU for several years as a virtual
> target for our OS. Many thanks to the community for providing this
> platform.
Hi,
Thanks for your interest.
> We've been working to get our OS running under QEMU 2.x and have
> identified a few bugs in QEMU, have made some enhancements, and are
> still tracking down some other curious behaviors. I'm looking for
> some guidance as to how, and whether, you'd like patches for the
> following.
Always interested in bug fixes. The e500 support probably doesn't get
a whole lot of attention these days, but you're proof that there are
at least a few people who care.
> 1. There is a defect in ppce500_spin.c:spin_kick() that creates an
> incorrectly sized TLB entry. This was reported as bug
> https://bugs.launchpad.net/qemu/+bug/1587535 I can provide a
> patch if desired.
Absolutely.
> 2. We have implemented the PPC "yield" instruction. I can provide a
> patch if desired.
Sounds good.
> 3. We're working on support for openpic timers. We're not finished,
> but it would be helpful to know if a patch is desired or if we
> should expect to maintain the changes independently.
I don't see a reason we wouldn't want it, unless it's horribly
invasive. By all means post patches, and I'll review as best I can.
> 4. We're currently tracking down why in our e500 (both unicore and
> multi-core) PPC QEMU 2.5 guest (x86 host), that with interrupts
> disabled, after enabling the decrementer and issuing a "wait"
> instruction QEMU continues to "busy loop", consuming an entire host
> CPU doing apparently nothing. As expected, issuing a "wait" prior
> to enabling the decrementer leaves the host process idle. We found
> the bug in the PPC "wait" instruction implementation that was
> independently reported and resolved last week, but that did not fix
> the problem. We also have our OS running on the g3beige and using
> MSR.POW which causes the host to "sleep", but we are having no joy
> with e500 and "wait". Any pointers would be appreciated. When we
> find something we'll report back.
Ok.
So, patches for ppc related code should be sent to myself and Alex
Graf <address@hidden>, co-maintainers for the target-ppc and related
code. You should CC both address@hidden and
address@hidden
I have a (frequently rebased) git tree where I stage ppc patches at:
https://github.com/dgibson/qemu/tree/ppc-for-2.7
--
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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- [Qemu-devel] Determining interest in PPC e500spin, yield, and openpic patches, alarson, 2016/06/13
- Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches, Mark Cave-Ayland, 2016/06/14
- Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches,
David Gibson <=
- Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches, alarson, 2016/06/15
- Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches, Thomas Huth, 2016/06/16
- [Qemu-devel] PPC e500spin pir improperly initialized, alarson, 2016/06/17
- Re: [Qemu-devel] PPC e500spin pir improperly initialized, Thomas Huth, 2016/06/20
- Re: [Qemu-devel] [Qemu-ppc] Determining interest in PPC e500spin, yield, and openpic patches, David Gibson, 2016/06/16