From patchwork Mon Nov 11 13:59:47 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Aneesh Kumar K.V" X-Patchwork-Id: 290292 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 CEBA52C0119 for ; Tue, 12 Nov 2013 01:00:09 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753625Ab3KKOAI (ORCPT ); Mon, 11 Nov 2013 09:00:08 -0500 Received: from e23smtp09.au.ibm.com ([202.81.31.142]:40257 "EHLO e23smtp09.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753520Ab3KKOAG (ORCPT ); Mon, 11 Nov 2013 09:00:06 -0500 Received: from /spool/local by e23smtp09.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Tue, 12 Nov 2013 00:00:02 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 6D8192BB0059; Tue, 12 Nov 2013 00:59:55 +1100 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id rABDg95W55115854; Tue, 12 Nov 2013 00:42:10 +1100 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id rABDxsaZ022231; Tue, 12 Nov 2013 00:59:55 +1100 Received: from skywalker.in.ibm.com ([9.77.202.172]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id rABDxqhL022206; Tue, 12 Nov 2013 00:59:52 +1100 From: "Aneesh Kumar K.V" To: agraf@suse.de, benh@kernel.crashing.org, paulus@samba.org Cc: linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, "Aneesh Kumar K.V" Subject: [PATCH] powerpc: book3s: kvm: Don't abuse host r2 in exit path Date: Mon, 11 Nov 2013 19:29:47 +0530 Message-Id: <1384178387-22993-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.2 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13111114-3568-0000-0000-00000489A0EF Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org From: "Aneesh Kumar K.V" We don't use PACATOC for PR. Avoid updating HOST_R2 with PR KVM mode when both HV and PR are enabled in the kernel. Without this we get the below crash (qemu) Unable to handle kernel paging request for data at address 0xffffffffffff8310 Faulting instruction address: 0xc00000000001d5a4 cpu 0x2: Vector: 300 (Data Access) at [c0000001dc53aef0] pc: c00000000001d5a4: .vtime_delta.isra.1+0x34/0x1d0 lr: c00000000001d760: .vtime_account_system+0x20/0x60 sp: c0000001dc53b170 msr: 8000000000009032 dar: ffffffffffff8310 dsisr: 40000000 current = 0xc0000001d76c62d0 paca = 0xc00000000fef1100 softe: 0 irq_happened: 0x01 pid = 4472, comm = qemu-system-ppc enter ? for help [c0000001dc53b200] c00000000001d760 .vtime_account_system+0x20/0x60 [c0000001dc53b290] c00000000008d050 .kvmppc_handle_exit_pr+0x60/0xa50 [c0000001dc53b340] c00000000008f51c kvm_start_lightweight+0xb4/0xc4 [c0000001dc53b510] c00000000008cdf0 .kvmppc_vcpu_run_pr+0x150/0x2e0 [c0000001dc53b9e0] c00000000008341c .kvmppc_vcpu_run+0x2c/0x40 [c0000001dc53ba50] c000000000080af4 .kvm_arch_vcpu_ioctl_run+0x54/0x1b0 [c0000001dc53bae0] c00000000007b4c8 .kvm_vcpu_ioctl+0x478/0x730 [c0000001dc53bca0] c0000000002140cc .do_vfs_ioctl+0x4ac/0x770 [c0000001dc53bd80] c0000000002143e8 .SyS_ioctl+0x58/0xb0 [c0000001dc53be30] c000000000009e58 syscall_exit+0x0/0x98 --- Exception: c00 (System Call) at 00001fffff960160 SP (1ffffecbe3c0) is in userspace These changes were originally part of http://mid.gmane.org/20130806042205.GR19254@iris.ozlabs.ibm.com Signed-off-by: Aneesh Kumar K.V Acked-by: Paul Mackerras --- arch/powerpc/include/asm/kvm_book3s_asm.h | 1 + arch/powerpc/kernel/asm-offsets.c | 1 + arch/powerpc/kvm/book3s_hv_rmhandlers.S | 7 +++---- 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_book3s_asm.h b/arch/powerpc/include/asm/kvm_book3s_asm.h index 0bd9348..69fe837 100644 --- a/arch/powerpc/include/asm/kvm_book3s_asm.h +++ b/arch/powerpc/include/asm/kvm_book3s_asm.h @@ -79,6 +79,7 @@ struct kvmppc_host_state { ulong vmhandler; ulong scratch0; ulong scratch1; + ulong scratch2; u8 in_guest; u8 restore_hid5; u8 napping; diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 8e6ede6..841a4c8 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -583,6 +583,7 @@ int main(void) HSTATE_FIELD(HSTATE_VMHANDLER, vmhandler); HSTATE_FIELD(HSTATE_SCRATCH0, scratch0); HSTATE_FIELD(HSTATE_SCRATCH1, scratch1); + HSTATE_FIELD(HSTATE_SCRATCH2, scratch2); HSTATE_FIELD(HSTATE_IN_GUEST, in_guest); HSTATE_FIELD(HSTATE_RESTORE_HID5, restore_hid5); HSTATE_FIELD(HSTATE_NAPPING, napping); diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 339aa5e..16f7654 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -750,15 +750,14 @@ kvmppc_interrupt_hv: * guest CR, R12 saved in shadow VCPU SCRATCH1/0 * guest R13 saved in SPRN_SCRATCH0 */ - /* abuse host_r2 as third scratch area; we get r2 from PACATOC(r13) */ - std r9, HSTATE_HOST_R2(r13) + std r9, HSTATE_SCRATCH2(r13) lbz r9, HSTATE_IN_GUEST(r13) cmpwi r9, KVM_GUEST_MODE_HOST_HV beq kvmppc_bad_host_intr #ifdef CONFIG_KVM_BOOK3S_PR_POSSIBLE cmpwi r9, KVM_GUEST_MODE_GUEST - ld r9, HSTATE_HOST_R2(r13) + ld r9, HSTATE_SCRATCH2(r13) beq kvmppc_interrupt_pr #endif /* We're now back in the host but in guest MMU context */ @@ -778,7 +777,7 @@ kvmppc_interrupt_hv: std r6, VCPU_GPR(R6)(r9) std r7, VCPU_GPR(R7)(r9) std r8, VCPU_GPR(R8)(r9) - ld r0, HSTATE_HOST_R2(r13) + ld r0, HSTATE_SCRATCH2(r13) std r0, VCPU_GPR(R9)(r9) std r10, VCPU_GPR(R10)(r9) std r11, VCPU_GPR(R11)(r9)