linux-kernel - [PATCH 4.14 14/49] KVM: PPC: Book3S HV: trace

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Date:   Tue, 17 Apr 2018 17:58:53 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Nicholas Piggin <npiggin@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 4.14 14/49] KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Piggin <npiggin@...il.com>

commit 19ce7909ed11c49f7eddf59e7f49cd3062bf83d5 upstream.

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: 0428491cba92 ("powerpc/mm: Trace tlbie(l) instructions")
Cc: stable@...r.kernel.org # v4.13+
Signed-off-by: Nicholas Piggin <npiggin@...il.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/powerpc/kvm/book3s_hv_rm_mmu.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -447,8 +447,6 @@ static void do_tlbies(struct kvm *kvm, u
 		for (i = 0; i < npages; ++i) {
 			asm volatile(PPC_TLBIE_5(%0,%1,0,0,0) : :
 				     "r" (rbvalues[i]), "r" (kvm->arch.lpid));
-			trace_tlbie(kvm->arch.lpid, 0, rbvalues[i],
-				kvm->arch.lpid, 0, 0, 0);
 		}
 		asm volatile("eieio; tlbsync; ptesync" : : : "memory");
 		kvm->arch.tlbie_lock = 0;
@@ -458,8 +456,6 @@ static void do_tlbies(struct kvm *kvm, u
 		for (i = 0; i < npages; ++i) {
 			asm volatile(PPC_TLBIEL(%0,%1,0,0,0) : :
 				     "r" (rbvalues[i]), "r" (0));
-			trace_tlbie(kvm->arch.lpid, 1, rbvalues[i],
-				0, 0, 0, 0);
 		}
 		asm volatile("ptesync" : : : "memory");
 	}