From patchwork Mon Jun 2 15:50:13 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mihai Caraman X-Patchwork-Id: 354972 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 20BEE14009E for ; Tue, 3 Jun 2014 01:50:36 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751251AbaFBPuf (ORCPT ); Mon, 2 Jun 2014 11:50:35 -0400 Received: from mail-by2lp0243.outbound.protection.outlook.com ([207.46.163.243]:14358 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752166AbaFBPud (ORCPT ); Mon, 2 Jun 2014 11:50:33 -0400 Received: from BY2PR03CA040.namprd03.prod.outlook.com (10.141.249.13) by BY2PR03MB506.namprd03.prod.outlook.com (10.141.143.18) with Microsoft SMTP Server (TLS) id 15.0.949.11; Mon, 2 Jun 2014 15:50:30 +0000 Received: from BN1BFFO11FD040.protection.gbl (2a01:111:f400:7c10::1:158) by BY2PR03CA040.outlook.office365.com (2a01:111:e400:2c5d::13) with Microsoft SMTP Server (TLS) id 15.0.954.9 via Frontend Transport; Mon, 2 Jun 2014 15:50:30 +0000 Received: from tx30smr01.am.freescale.net (192.88.168.50) by BN1BFFO11FD040.mail.protection.outlook.com (10.58.144.103) with Microsoft SMTP Server (TLS) id 15.0.949.9 via Frontend Transport; Mon, 2 Jun 2014 15:50:29 +0000 Received: from fsr-fed1764-012.ea.freescale.net (fsr-fed1764-012-010171073213.ea.freescale.net [10.171.73.213]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with ESMTP id s52FoPRf010153; Mon, 2 Jun 2014 08:50:28 -0700 From: Mihai Caraman To: CC: , , Mihai Caraman Subject: [PATCH 1/4 v3] KVM: PPC: e500mc: Revert "add load inst fixup" Date: Mon, 2 Jun 2014 18:50:13 +0300 Message-ID: <1401724216-26486-2-git-send-email-mihai.caraman@freescale.com> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1401724216-26486-1-git-send-email-mihai.caraman@freescale.com> References: <1401724216-26486-1-git-send-email-mihai.caraman@freescale.com> X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:192.88.168.50; CTRY:US; IPV:CAL; IPV:NLI; EFV:NLI; SFV:NSPM; SFS:(6009001)(199002)(189002)(77156001)(74662001)(92726001)(6806004)(84676001)(80022001)(50466002)(21056001)(102836001)(74502001)(92566001)(26826002)(104166001)(68736004)(88136002)(4396001)(86362001)(85852003)(97736001)(50226001)(87936001)(87286001)(31966008)(99396002)(33646001)(77982001)(76482001)(76176999)(81342001)(20776003)(77096999)(19580405001)(81542001)(83322001)(93916002)(44976005)(79102001)(89996001)(50986999)(47776003)(48376002)(64706001)(46102001)(104016001)(62966002)(36756003)(83072002)(19580395003); DIR:OUT; SFP:; SCL:1; SRVR:BY2PR03MB506; H:tx30smr01.am.freescale.net; FPR:; MLV:ovrnspm; PTR:InfoDomainNonexistent; A:1; MX:1; LANG:en; MIME-Version: 1.0 X-Microsoft-Antispam: BL:0; ACTION:Default; RISK:Low; SCL:0; SPMLVL:NotSpam; PCL:0; RULEID: X-Forefront-PRVS: 0230B09AC4 Received-SPF: Fail (: domain of freescale.com does not designate 192.88.168.50 as permitted sender) receiver=; client-ip=192.88.168.50; helo=tx30smr01.am.freescale.net; Authentication-Results: spf=fail (sender IP is 192.88.168.50) smtp.mailfrom=mihai.caraman@freescale.com; X-OriginatorOrg: freescale.com Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org The commit 1d628af7 "add load inst fixup" made an attempt to handle failures generated by reading the guest current instruction. The fixup code that was added works by chance hiding the real issue. Load external pid (lwepx) instruction, used by KVM to read guest instructions, is executed in a substituted guest translation context (EPLC[EGS] = 1). In consequence lwepx's TLB error and data storage interrupts need to be handled by KVM, even though these interrupts are generated from host context (MSR[GS] = 0) where lwepx is executed. Currently, KVM hooks only interrupts generated from guest context (MSR[GS] = 1), doing minimal checks on the fast path to avoid host performance degradation. As a result, the host kernel handles lwepx faults searching the faulting guest data address (loaded in DEAR) in its own Logical Partition ID (LPID) 0 context. In case a host translation is found the execution returns to the lwepx instruction instead of the fixup, the host ending up in an infinite loop. Revert the commit "add load inst fixup". lwepx issue will be addressed in a subsequent patch without needing fixup code. Signed-off-by: Mihai Caraman --- v3: - no change v2: - reworked patch description arch/powerpc/kvm/bookehv_interrupts.S | 26 +------------------------- 1 file changed, 1 insertion(+), 25 deletions(-) diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S index a1712b8..6ff4480 100644 --- a/arch/powerpc/kvm/bookehv_interrupts.S +++ b/arch/powerpc/kvm/bookehv_interrupts.S @@ -29,7 +29,6 @@ #include #include #include -#include #ifdef CONFIG_64BIT #include @@ -164,32 +163,9 @@ PPC_STL r30, VCPU_GPR(R30)(r4) PPC_STL r31, VCPU_GPR(R31)(r4) mtspr SPRN_EPLC, r8 - - /* disable preemption, so we are sure we hit the fixup handler */ - CURRENT_THREAD_INFO(r8, r1) - li r7, 1 - stw r7, TI_PREEMPT(r8) - isync - - /* - * In case the read goes wrong, we catch it and write an invalid value - * in LAST_INST instead. - */ -1: lwepx r9, 0, r5 -2: -.section .fixup, "ax" -3: li r9, KVM_INST_FETCH_FAILED - b 2b -.previous -.section __ex_table,"a" - PPC_LONG_ALIGN - PPC_LONG 1b,3b -.previous - + lwepx r9, 0, r5 mtspr SPRN_EPLC, r3 - li r7, 0 - stw r7, TI_PREEMPT(r8) stw r9, VCPU_LAST_INST(r4) .endif