From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40G0dK4VltzF2B6 for ; Wed, 4 Apr 2018 06:12:53 +1000 (AEST) Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w33KAeCg044033 for ; Tue, 3 Apr 2018 16:12:50 -0400 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0b-001b2d01.pphosted.com with ESMTP id 2h4fuqhrhn-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Tue, 03 Apr 2018 16:12:50 -0400 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 3 Apr 2018 21:12:48 +0100 From: "Naveen N. Rao" To: Michael Ellerman , Steven Rostedt Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras , Nicholas Piggin , Anton Blanchard , sathnaga@linux.vnet.ibm.com Subject: [PATCH v4 02/10] powerpc64/ftrace: Disable ftrace during kvm guest entry/exit Date: Wed, 4 Apr 2018 01:42:17 +0530 In-Reply-To: References: In-Reply-To: References: Message-Id: List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , During guest entry/exit, we switch over to/from the guest MMU context. While doing so, we set our state to KVM_GUEST_MODE_HOST_HV to note down the fact that we cannot take any exceptions in the hypervisor code. Since ftrace may be enabled and since it can result in us taking a trap, disable ftrace by setting paca->ftrace_enabled to zero. Once we exit the guest and restore host MMU context, we re-enable ftrace. Signed-off-by: Naveen N. Rao --- arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index bd63fa8a08b5..6f2d7206a12b 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -598,6 +598,10 @@ kvmppc_hv_entry: /* Save R1 in the PACA */ std r1, HSTATE_HOST_R1(r13) + /* Disable ftrace since we can't take a trap any more */ + li r6, 0 + stb r6, PACA_FTRACE_ENABLED(r13) + li r6, KVM_GUEST_MODE_HOST_HV stb r6, HSTATE_IN_GUEST(r13) @@ -2078,6 +2082,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300) /* Unset guest mode */ li r0, KVM_GUEST_MODE_NONE stb r0, HSTATE_IN_GUEST(r13) + li r0, 1 + stb r0, PACA_FTRACE_ENABLED(r13) lwz r12, STACK_SLOT_TRAP(r1) /* return trap # in r12 */ ld r0, SFS+PPC_LR_STKOFF(r1) @@ -3547,6 +3553,8 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_RADIX) ld r8, KVM_HOST_LPCR(r10) mtspr SPRN_LPCR, r8 isync + li r0, 1 + stb r0, PACA_FTRACE_ENABLED(r13) li r0, KVM_GUEST_MODE_NONE stb r0, HSTATE_IN_GUEST(r13) -- 2.16.2