seems I finally found what upset kqemu on amd64 SMP... shared
gdt! (please test new patch :)
nox at jelal.kn-bremen.de
Sun May 11 21:09:55 UTC 2008
On Sun, May 11, 2008 at 12:27:45PM -0700, Bakul Shah wrote:
> With your latest patch things are looking pretty good!
> - Multiple qemus on a MP FreeBSD amd64 works with kqemu
> enabled for user code. Some running 64 bit kernels
> (freebsd), some running 32 bit kernels (freebsd and plan9).
> - Nested qemus work! That is, qemu*x86_64 under qemu*x86_64,
> both with user mode kqemu. A 32 bit 7.0 kernel under it ran
> fine. Ideally qemus should nest as long as there is enough
> memory (a torture test for emulation fidelity).
> - As mentioned in another thread netbooting works well enough
> but you have to use pxeboot from -current and append a byte
> to it to work around an etherboot tftp bug.
> Now the bugs (probably most having to do with qemu/kqemu,
> not the freebsd port):
> 1. kernel mode kqemu seems to cause crashes. Generally this
> happens right after the guest freebsd kernel comes up.
Yeah I posted one of those on the qemu list,
32 bit linux guests seem to work fine tho at least.
> 2. After the above crash VM reboots automatically but now it
> can't find the root device so it hangs at the root
> selection prompt.
> 3. Ocassionally plan9 and (less often FreeBSD) crashes on
> boot. Looks like a race condition of some sort. If they
> boot, there are no further problems traceable to
> 4. "calcru: runtime went backwards from <t1> usec to <t2> for
> pid <pid> (<cmd>)" is back!
Well, the clock never was very accurate thats true...
> Also, ntpd seems to get very
> confused and after syncing with another clock shifts
> mostly correct time by a few hours.
> 5. An initial getty gets killed as it "exceeded maximum CPU limit"
> This could an emulation bug or related to time issues.
> Random thoughts:
> - If qemu is made scriptable we can automate a lot of
> testing. For qemu/kqemu and freebsd.
Hmm what exactly do you want to script there?
> - We need to add a section on qemu in the handbook.
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