[PATCH 1/2] KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode

[Balbir Singh]

On Fri, Apr 6, 2018 at 3:56 AM, Nicholas Piggin <npiggin at gmail.com> wrote:
> This crashes with a "Bad real address for load" attempting to load
> from the vmalloc region in realmode (faulting address is in DAR).
>
>   Oops: Bad interrupt in KVM entry/exit code, sig: 6 [#1]
>   LE SMP NR_CPUS=2048 NUMA PowerNV
>   CPU: 53 PID: 6582 Comm: qemu-system-ppc Not tainted 4.16.0-01530-g43d1859f0994
>   NIP:  c0000000000155ac LR: c0000000000c2430 CTR: c000000000015580
>   REGS: c000000fff76dd80 TRAP: 0200   Not tainted  (4.16.0-01530-g43d1859f0994)
>   MSR:  9000000000201003 <SF,HV,ME,RI,LE>  CR: 48082222  XER: 00000000
>   CFAR: 0000000102900ef0 DAR: d00017fffd941a28 DSISR: 00000040 SOFTE: 3
>   NIP [c0000000000155ac] perf_trace_tlbie+0x2c/0x1a0
>   LR [c0000000000c2430] do_tlbies+0x230/0x2f0
>
> I suspect the reason is the per-cpu data is not in the linear chunk.
> This could be restored if that was able to be fixed, but for now,
> just remove the tracepoints.

Could you share the stack trace as well? I've not observed this in my testing.
May be I don't have as many cpus. I presume your talking about the per cpu
data offsets for per cpu trace data?

Balbir Singh.