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xen/timer: make xen timer optional
AcceptedPublic

Authored by ehem_freebsd_m5p.com on Mar 3 2021, 4:33 PM.

Details

Reviewers
royger
mhorne
Summary

The timer is not used on ARM.

Adapted-to-HEAD-by: Elliott Mitchell <ehem+freebsd@m5p.com>

Diff Detail

Repository
rS FreeBSD src repository - subversion
Lint
Lint OK
Unit
No Unit Test Coverage
Build Status
Buildable 37541
Build 34430: arc lint + arc unit

Event Timeline

Some minor comments.

sys/amd64/conf/GENERIC
383

I don't think XENHVM strictly depends on xentimer (as it does on xenpci). It's the other way around, xentimer depends on XENHVM, but you should be able to build a kernel with XENHVM but without xentimer.

387

Could you please append a comment with 'Xen x86 PV timer device' , like it's done for the other lines?

Getting one of the adjustments in.

The one comment is done. Thinking about the wording for the other a bit more. The comment came from Julien Grall's original patch, so I can believe time having changed things or the original thinking being mistaken.

sys/amd64/conf/GENERIC
383

I don't think XENHVM strictly depends on xentimer (as it does on xenpci). It's the other way around, xentimer depends on XENHVM, but you should be able to build a kernel with XENHVM but without xentimer.

Could I have some certainty here? Does an x86 kernel built with XENHVM, but xentimer disabled boot successfully?

sys/amd64/conf/GENERIC
383

Yes, it will just use another timer, there are plenty on HVM guests, and on PVH it should resort to the local APIC timer.

Adjust comment along proposed line. Hopefully this language works.

This revision is now accepted and ready to land.Apr 6 2021, 9:27 AM