Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754713AbdDJPyg (ORCPT ); Mon, 10 Apr 2017 11:54:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:38061 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754419AbdDJPeb (ORCPT ); Mon, 10 Apr 2017 11:34:31 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Huth , Paul Mackerras , Sumit Semwal , Jiri Slaby Subject: [PATCH 3.12 049/142] KVM: PPC: Book3S PR: Fix illegal opcode emulation Date: Mon, 10 Apr 2017 17:32:10 +0200 Message-Id: X-Mailer: git-send-email 2.12.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2119 Lines: 53 From: Thomas Huth 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 708e75a3ee750dce1072134e630d66c4e6eaf63c upstream. If kvmppc_handle_exit_pr() calls kvmppc_emulate_instruction() to emulate one instruction (in the BOOK3S_INTERRUPT_H_EMUL_ASSIST case), it calls kvmppc_core_queue_program() afterwards if kvmppc_emulate_instruction() returned EMULATE_FAIL, so the guest gets an program interrupt for the illegal opcode. However, the kvmppc_emulate_instruction() also tried to inject a program exception for this already, so the program interrupt gets injected twice and the return address in srr0 gets destroyed. All other callers of kvmppc_emulate_instruction() are also injecting a program interrupt, and since the callers have the right knowledge about the srr1 flags that should be used, it is the function kvmppc_emulate_instruction() that should _not_ inject program interrupts, so remove the kvmppc_core_queue_program() here. This fixes the issue discovered by Laurent Vivier with kvm-unit-tests where the logs are filled with these messages when the test tries to execute an illegal instruction: Couldn't emulate instruction 0x00000000 (op 0 xop 0) kvmppc_handle_exit_pr: emulation at 700 failed (00000000) Signed-off-by: Thomas Huth Reviewed-by: Alexander Graf Tested-by: Laurent Vivier Signed-off-by: Paul Mackerras Cc: Sumit Semwal Signed-off-by: Jiri Slaby --- arch/powerpc/kvm/emulate.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c index 751cd45f65a0..128651aa8437 100644 --- a/arch/powerpc/kvm/emulate.c +++ b/arch/powerpc/kvm/emulate.c @@ -471,7 +471,6 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu) advance = 0; printk(KERN_ERR "Couldn't emulate instruction 0x%08x " "(op %d xop %d)\n", inst, get_op(inst), get_xop(inst)); - kvmppc_core_queue_program(vcpu, 0); } } -- 2.12.2