[20.04 FEAT] qemu: P9 guest - XIVE support/exploitation

[bugproxy]

== Comment: #0 - Frank P. Novak <email address hidden> - 2016-08-12 10:15:22 ==

[FEATURE] P9 guest - XIVE support/exploitation

[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

[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

[Christian Ehrhardt  (paelzer)]

Also this might be 18.04 according to the tagging, but if known and ready please let me know.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2017-06-14 08:48 EDT-------
Hi Christian,

This is QEMU 2.11 and linux 4.13 at minimum. So definitely not a Ubuntu 17.10 thing. This is targeted for Ubuntu 18.04.

------- Comment From <email address hidden> 2017-06-14 08:57 EDT-------
(In reply to comment #6)
> Hi,
> especially for new features I assume that you'll do the testing, but some
> sort of extra info on ...
>
> a) what it does

POWER9 has a new interrupt controller called XIVE (eXternal Interrupt Virtualization Engine). This new interrupt controller will provide considerable performance enhancements for interrupts being routed to guests when compared to the previous interrupt controller, XICS (eXternal Interrupt Controller Specification), used on POWER8 processors.

This feature is about building support for a guest to use the XIVE interrupt controller. If this is not available the guest will continue to use emulated XICS as available on POWER8 guets.

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

We need a host with a kernel and QEMU with the necessary support to export XIVE directly to the guest, plus a guest kernel that can use XIVE. This combination should be enough to make the guest automatically use XIVE. This can be easily checked in dmesg or /proc/interrupts.

> c) implications/regressions

If XIVE is not working the guest will use XICS. This can be checked in dmesg and /proc/interrupts. If no interrupt controller is working this will be easily noticed because the guest will not boot.

> d) HW constraints (min HW level, FW, ...)

This needs POWER9 hardware.

[Dimitri John Ledkov (xnox)]

This is targetted at 18.10 now, are there new package version requirements?

We are currently targetting qemu 2.11 & linux kernel 4.15. Is that not sufficient to exploit P9 guest XIVE?

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2018-02-14 13:01 EDT-------
XIVE in a guest is not yet available upstream.

[Andrew Cloke (andrew-cloke)]

From comment #7, waiting for "XIVE in a guest" support to land upstream.

[Manoj Iyer (manjo)]

Since this is an 18.10 feature request marking priority a low for now.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2018-08-17 15:23 EDT-------
Feature still being worked upstream. Postponing to Ubuntu 19.04.

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2019-03-13 16:28 EDT-------
This is still being discussed upstream.

[Andrew Cloke (andrew-cloke)]

Note: Feature Freeze for 19.10 is 22nd August.

[Andrew Cloke (andrew-cloke)]

We are now past feature freeze for 19.10. Should this be re-targeted to 20.04?

[bugproxy (bugproxy)]

------- Comment From <email address hidden> 2019-10-08 12:24 EDT-------
Everything for this support did go upstream is already part of 19.10 so we can close.

[Andrew Cloke (andrew-cloke)]

Thanks Michael. Closing out.