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From: Nicholas Piggin <npiggin@gmail.com>
To: kvm-ppc@vger.kernel.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@ozlabs.org>,
	Balbir Singh <bsingharora@gmail.com>
Subject: [PATCH 1/2] KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode
Date: Fri,  6 Apr 2018 03:56:30 +1000	[thread overview]
Message-ID: <20180405175631.31381-2-npiggin@gmail.com> (raw)
In-Reply-To: <20180405175631.31381-1-npiggin@gmail.com>

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

diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index e1c083fbe434..78e6a392330f 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -470,8 +470,6 @@ static void do_tlbies(struct kvm *kvm, unsigned long *rbvalues,
 		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);
 		}
 
 		if (cpu_has_feature(CPU_FTR_P9_TLBIE_BUG)) {
@@ -492,8 +490,6 @@ static void do_tlbies(struct kvm *kvm, unsigned long *rbvalues,
 		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");
 	}
-- 
2.16.3

  reply	other threads:[~2018-04-05 17:56 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-05 17:56 [PATCH 0/2] KVM powerpc tlbie scalability improvement Nicholas Piggin
2018-04-05 17:56 ` Nicholas Piggin [this message]
2018-04-08 10:17   ` [PATCH 1/2] KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode Balbir Singh
2018-04-08 13:41     ` Nicholas Piggin
2018-04-10  3:21       ` Michael Ellerman
2018-04-10  5:55         ` Naveen N. Rao
2018-04-10  6:10           ` Nicholas Piggin
2018-04-11 14:49   ` [1/2] " Michael Ellerman
2018-04-05 17:56 ` [PATCH 2/2] KVM: PPC: Book3S HV: lockless tlbie for HPT hcalls Nicholas Piggin
2018-04-06  5:39   ` Nicholas Piggin
2018-04-06  6:12   ` Michael Ellerman
2018-05-10  5:30     ` Paul Mackerras
2018-05-14  4:04       ` Michael Ellerman
2018-05-17  3:53         ` Paul Mackerras

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