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Re: CVS commit: src/sys/arch (lapic va change)

Upon further investigation it seems that the lapic va change is not the cause of the hangs I've been seeing. I'm currently looking further to find the real root cause.

On Sat, 17 Dec 2016, Maxime Villard wrote:

Le 15/12/2016 à 09:21, Paul Goyette a écrit :
Module Name:    src
Committed By:   maxv
Date:           Sun Dec 11 08:31:53 UTC 2016

Modified Files:
        src/sys/arch/amd64/amd64: machdep.c
        src/sys/arch/i386/i386: machdep.c
        src/sys/arch/x86/x86: pmap.c

Log Message:
Kenter local_apic_va to a fake physical page, because our x86
implementation expects this va to be valid even if no lapic is
present; which probably is a bug in itself, but let's just reproduce
the old behavior and rehide that bug.

This change (and the subsequent fix for the build break) breaks the
installation process when running under pkgsrc/emulators/qemu-2.7.0nb1

Booting the install media image gets as far as the end of device
auto-configuration, and hangs after reporting the boot device and
/path/to/modules.  It never gets to starting the init(8) process.

Reverting this fix (and the build break fix) restores the ability to
finish booting, and actually gets into sysinst.

I don't know what the correct fix is, but I think we should revert this
commit (at least for amd64, not sure about i386) until it is better
understood and can be fixed properly.

This problem doesn't seem to be affecting the rel-eng amd64 test-bed,
probably because it is likely running an older version of qemu?

Given what you say, I would tend to believe that it is not related to lapic.
The fix just reproduces the old behavior, the exact same way. The only place
where things could go wrong is before the pa is kentered, which is done way
before the autoconfiguration. I guess you were running a generic amd64? And
I guess this change [1] does not fix the issue?



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