[17.10 FEAT] qemu: P8-Compat mode - HPT to guest

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== Comment: #0 - Frank P. Novak <email address hidden> - 2016-08-12 14:49:38 ==

[Feature] UbuntuKVM: qemu: P8-Compat mode - HPT to guest

[Christian Ehrhardt  (paelzer)]

Hi,
thanks for starting the tracking of all related changes.
Is this in qemu 2.9, if not is it at least upstream and which are the related commits?

[Christian Ehrhardt  (paelzer)]

Hi,
especially for new features I assume that you'll do the testing, but some sort of extra info on ...

a) what it does
b) how to use/exploit it as a user
c) implications/regressions
d) HW constraints (min HW level, FW, ...)

... would be really great

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------- Comment From <email address hidden> 2017-05-23 12:24 EDT-------
(In reply to comment #4)
> Hi,
> thanks for starting the tracking of all related changes.
> Is this in qemu 2.9, if not is it at least upstream and which are the
> related commits?

This is QEMU 2.10. Sam might be able to post here the relevant commit IDs.

------- Comment From <email address hidden> 2017-05-23 12:26 EDT-------
(In reply to comment #5)
> Hi,
> especially for new features I assume that you'll do the testing, but some
> sort of extra info on ...
>
> a) what it does

Hash Page Tables is the page table structure used in POWER8 and previous machines. POWER9 supports both HPT and Radix Page Tables (RPT), but our focus on POWER9 guests is with RPT for now.

> b) how to use/exploit it as a user

Just boot a Ubuntu guest built for POWER8 and see if it boots correctly using HPT. There will be messages in the log stating this.

> c) implications/regressions
> d) HW constraints (min HW level, FW, ...)

You need POWER9 hardware to test this.

>
> ... would be really great

[Christian Ehrhardt  (paelzer)]

Ping - Since 2.10 likely will be too late to make 17.10 polling for related commit ID's for p9 support

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------- Comment From <email address hidden> 2017-06-19 11:02 EDT-------
(In reply to comment #11)
> Ping - Since 2.10 likely will be too late to make 17.10 polling for related
> commit ID's for p9 support

I am working to get the commit IDs needed and will post them soon.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2017-08-09 13:14 EDT-------
(In reply to comment #11)
> Ping - Since 2.10 likely will be too late to make 17.10 polling for related
> commit ID's for p9 support

I haven't sent the commit IDs yet because I could not validate the whole HPT scenario on P( yet.
The only patches that should be needed on that are related to the basic P9 enablement. I will post the commit IDs again here:

40fda982f2e ppc: remove cannot_destroy_with_object_finalize_yet
f3d9f303acb target/ppc: Improve accuracy of guest HTM availability on P8s
c64abd1f9c7 spapr: Add ibm,processor-radix-AP-encodings to the device tree
cf1c4cce7c0 target-ppc: support KVM_CAP_PPC_MMU_RADIX, KVM_CAP_PPC_MMU_HASH_V3
d77a98b015 target/ppc: Add new H-CALL shells for in memory table translation
b4db54132ff target/ppc: Implement H_REGISTER_PROCESS_TABLE H_CALL
86d5771a5a spapr: move spapr_populate_pa_features()
9fb4541f580 spapr: Enable ISA 3.0 MMU mode selection via CAS
e957f6a9b92 spapr: Workaround for broken radix guests
9bf502fe127f spapr: Don't accidentally advertise HTM support on POWER9
ccd531b9c9d target/ppc: Add ibm,processor-radix-AP-encodings for TCG
5f3066d8b10 target/ppc: Allow workarounds for POWER9 DD1

The patches applied straight forward so I've been able to test it and also created a branch which contains 2.9 + those patches back ported: https://github.com/alinefm/qemu/tree/2.9-p9-support

But there is a FFE (Feature Freeze Exception) https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1699968 to get QEMU 2.10 into Ubuntu 17.10
So most probably, no backport will be needed.

Also the tests on QEMU 2.10-rc2 have already started https://trello.com/c/zGBvQFvQ/143-virt-stack-merges-for-1710-qemu-libvirt?menu=filter&filter=virt

[Christian Ehrhardt  (paelzer)]

I know we worked much closer together and things should be good for all I've heard, but thereby forgot to update all these bugs. Also the usual automatic bug close didn't post here on the uploads.
So we need to update all those - it was a lot of effort to get all that in time, but the final qemu 2.10 is now pushed to Artful and given former comments this should be fix-released.

Please verify your cases if anything might be left.
There were a few that I know got punted to qemu 2.11 - I left those open for now.
If one of the cases I close are actually one of these please reopen and clarify what will be needed.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2018-02-14 13:34 EDT-------
POWER8-compat mode should be working on Ubuntu 18.04. Closing.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2018-02-15 01:18 EDT-------
We have not attempted this yet.. there are couple of issues

1. DD 2.2 machine availability. Even though we have workarounds for compat mode on < DD 2.2.. that's not what customers would use
2. chicken switches for compat mode is still not in FW yet.. refer https://github.com/open-power/boston-openpower/issues/963