Re: Xen MP panics in cpu_switchto()

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Jan 13, 2020 at 12:02:13PM +0000, Andrew Doran wrote:
> Ah yes it does, I saw something that made me think it affected x86_64 only. 
> I'll make the change on i386 too.

thanks.

Now I get a different panic:
[   1.0000000] vcpu0 at hypervisor0
[   1.0000000] vcpu0: 64 page colors
[   1.0000000] vcpu0: Intel(R) Core(TM)2 Duo CPU     E6550  @ 2.33GHz, id 0x6fb
[   1.0000000] vcpu0: node 0, package 0, core 1, smt 0
[   1.0000000] vcpu1 at hypervisor0
[   1.0000000] vcpu1: 2 page colors
[   1.0000000] vcpu1: starting
[   1.0000000] vcpu1: is started.
[   1.0000000] vcpu1: Intel(R) Core(TM)2 Duo CPU     E6550  @ 2.33GHz, id 0x6fb
[   1.0000000] vcpu1: node 0, package 0, core 0, smt 0
[...]
[   1.0000030] UVM: using package allocation scheme, 1 package(s) per bucket
[   1.0000030] Xen vcpu1 clock: using event channel 7
[   1.8809493] vcpu1: running
[   1.8809493] panic: kernel diagnostic assertion "prev != NULL" failed: file "/dsk/l1/misc/bouyer/HEAD/clean/src/sys/kern/kern_lwp.c", line 1021
[   1.8809493] cpu1: Begin traceback...
[   1.8809493] vpanic(c057f868,d77abf74,d77abf98,c03cc3e5,c057f868,c057f802,c05b0f71,c05b0ce4,3fd,0) at netbsd:vpanic+0x134
[   1.8809493] kern_assert(c057f868,c057f802,c05b0f71,c05b0ce4,3fd,0,0,0,c13a6900,c03c60c0) at netbsd:kern_assert+0x23
[   1.8809493] lwp_startup(0,c13a6900,8b1000,c0674200,0,c010007a,0,0,0,0) at netbsd:lwp_startup+0x155
[   1.8809493] cpu1: End traceback...

If I remove the call to cpu_switchto() in cpu_hatch() it boots, but it seems
that all user processes are running on cpu0 only ...
I can't see what extra work the cpu_switchto() could be doing that would
matters, execpt maybe the %epb/rbp init. Any idea ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--