Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752424AbdFSShP (ORCPT + 2 others); Mon, 19 Jun 2017 14:37:15 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:52436 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753560AbdFSShM (ORCPT ); Mon, 19 Jun 2017 14:37:12 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Thomas Huth , Paul Mackerras , Sumit Semwal , Jiri Slaby , Willy Tarreau Subject: [PATCH 3.10 165/268] KVM: PPC: Book3S PR: Fix illegal opcode emulation Date: Mon, 19 Jun 2017 20:31:04 +0200 Message-Id: <1497897167-14556-166-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1497897167-14556-1-git-send-email-w@1wt.eu> References: <1497897167-14556-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Thomas Huth 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 Signed-off-by: Willy Tarreau --- 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 631a265..50b482b 100644 --- a/arch/powerpc/kvm/emulate.c +++ b/arch/powerpc/kvm/emulate.c @@ -511,7 +511,6 @@ 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); } } -- 2.8.0.rc2.1.gbe9624a