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

On Thu, 2018-04-05 at 17:56:30 UTC, Nicholas Piggin 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.

Fixes: 0428491cba ("powerpc/mm: Trace tlbie(l) instructions")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/19ce7909ed11c49f7eddf59e7f49cd

cheers