From patchwork Wed May 6 09:50:08 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 6348101 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id A894DBEEE1 for ; Wed, 6 May 2015 09:50:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9EF1120225 for ; Wed, 6 May 2015 09:50:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 709E020270 for ; Wed, 6 May 2015 09:50:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751092AbbEFJuW (ORCPT ); Wed, 6 May 2015 05:50:22 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40489 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751084AbbEFJuR (ORCPT ); Wed, 6 May 2015 05:50:17 -0400 Received: from av-217-129-142-138.netvisao.pt ([217.129.142.138] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1Ypvxw-0001MG-R5; Wed, 06 May 2015 09:50:09 +0000 From: Luis Henriques To: James Hogan Cc: Paolo Bonzini , Paul Burton , Ralf Baechle , Gleb Natapov , linux-mips@linux-mips.org, kvm@vger.kernel.org, Luis Henriques , kernel-team@lists.ubuntu.com Subject: [3.16.y-ckt stable] Patch "MIPS: KVM: Handle MSA Disabled exceptions from guest" has been added to staging queue Date: Wed, 6 May 2015 10:50:08 +0100 Message-Id: <1430905808-25980-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 X-Extended-Stable: 3.16 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is a note to let you know that I have just added a patch titled MIPS: KVM: Handle MSA Disabled exceptions from guest to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt11. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ------ From 4065df8bc181b3c650c4c4383f80fb0d5deee877 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 6 Feb 2015 11:11:56 +0000 Subject: MIPS: KVM: Handle MSA Disabled exceptions from guest commit 98119ad53376885819d93dfb8737b6a9a61ca0ba upstream. Guest user mode can generate a guest MSA Disabled exception on an MSA capable core by simply trying to execute an MSA instruction. Since this exception is unknown to KVM it will be passed on to the guest kernel. However guest Linux kernels prior to v3.15 do not set up an exception handler for the MSA Disabled exception as they don't support any MSA capable cores. This results in a guest OS panic. Since an older processor ID may be being emulated, and MSA support is not advertised to the guest, the correct behaviour is to generate a Reserved Instruction exception in the guest kernel so it can send the guest process an illegal instruction signal (SIGILL), as would happen with a non-MSA-capable core. Fix this as minimally as reasonably possible by preventing kvm_mips_check_privilege() from relaying MSA Disabled exceptions from guest user mode to the guest kernel, and handling the MSA Disabled exception by emulating a Reserved Instruction exception in the guest, via a new handle_msa_disabled() KVM callback. Signed-off-by: James Hogan Cc: Paolo Bonzini Cc: Paul Burton Cc: Ralf Baechle Cc: Gleb Natapov Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org [ luis: backported to 3.16: files renamed: - arch/mips/kvm/emulate.c -> arch/mips/kvm/kvm_mips_emul.c - arch/mips/kvm/mips.c -> arch/mips/kvm/kvm_mips.c] Signed-off-by: Luis Henriques --- arch/mips/include/asm/kvm_host.h | 2 ++ arch/mips/kvm/kvm_mips.c | 4 ++++ arch/mips/kvm/kvm_mips_emul.c | 1 + arch/mips/kvm/kvm_trap_emul.c | 28 ++++++++++++++++++++++++++++ 4 files changed, 35 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h index b0aa95565752..5a8defbad431 100644 --- a/arch/mips/include/asm/kvm_host.h +++ b/arch/mips/include/asm/kvm_host.h @@ -326,6 +326,7 @@ enum mips_mmu_types { #define T_TRAP 13 /* Trap instruction */ #define T_VCEI 14 /* Virtual coherency exception */ #define T_FPE 15 /* Floating point exception */ +#define T_MSADIS 21 /* MSA disabled exception */ #define T_WATCH 23 /* Watch address reference */ #define T_VCED 31 /* Virtual coherency data */ @@ -578,6 +579,7 @@ struct kvm_mips_callbacks { int (*handle_syscall)(struct kvm_vcpu *vcpu); int (*handle_res_inst)(struct kvm_vcpu *vcpu); int (*handle_break)(struct kvm_vcpu *vcpu); + int (*handle_msa_disabled)(struct kvm_vcpu *vcpu); int (*vm_init)(struct kvm *kvm); int (*vcpu_init)(struct kvm_vcpu *vcpu); int (*vcpu_setup)(struct kvm_vcpu *vcpu); diff --git a/arch/mips/kvm/kvm_mips.c b/arch/mips/kvm/kvm_mips.c index d84f96e51349..59298b97ac39 100644 --- a/arch/mips/kvm/kvm_mips.c +++ b/arch/mips/kvm/kvm_mips.c @@ -1156,6 +1156,10 @@ int kvm_mips_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu) ret = kvm_mips_callbacks->handle_break(vcpu); break; + case T_MSADIS: + ret = kvm_mips_callbacks->handle_msa_disabled(vcpu); + break; + default: kvm_err ("Exception Code: %d, not yet handled, @ PC: %p, inst: 0x%08x BadVaddr: %#lx Status: %#lx\n", diff --git a/arch/mips/kvm/kvm_mips_emul.c b/arch/mips/kvm/kvm_mips_emul.c index 8d4840090082..2071472bc3c4 100644 --- a/arch/mips/kvm/kvm_mips_emul.c +++ b/arch/mips/kvm/kvm_mips_emul.c @@ -2204,6 +2204,7 @@ kvm_mips_check_privilege(unsigned long cause, uint32_t *opc, case T_SYSCALL: case T_BREAK: case T_RES_INST: + case T_MSADIS: break; case T_COP_UNUSABLE: diff --git a/arch/mips/kvm/kvm_trap_emul.c b/arch/mips/kvm/kvm_trap_emul.c index 693f952b2fbb..0c521c356553 100644 --- a/arch/mips/kvm/kvm_trap_emul.c +++ b/arch/mips/kvm/kvm_trap_emul.c @@ -333,6 +333,33 @@ static int kvm_trap_emul_handle_break(struct kvm_vcpu *vcpu) return ret; } +static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu) +{ + struct kvm_run *run = vcpu->run; + uint32_t __user *opc = (uint32_t __user *) vcpu->arch.pc; + unsigned long cause = vcpu->arch.host_cp0_cause; + enum emulation_result er = EMULATE_DONE; + int ret = RESUME_GUEST; + + /* No MSA supported in guest, guest reserved instruction exception */ + er = kvm_mips_emulate_ri_exc(cause, opc, run, vcpu); + + switch (er) { + case EMULATE_DONE: + ret = RESUME_GUEST; + break; + + case EMULATE_FAIL: + run->exit_reason = KVM_EXIT_INTERNAL_ERROR; + ret = RESUME_HOST; + break; + + default: + BUG(); + } + return ret; +} + static int kvm_trap_emul_vm_init(struct kvm *kvm) { return 0; @@ -472,6 +499,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = { .handle_syscall = kvm_trap_emul_handle_syscall, .handle_res_inst = kvm_trap_emul_handle_res_inst, .handle_break = kvm_trap_emul_handle_break, + .handle_msa_disabled = kvm_trap_emul_handle_msa_disabled, .vm_init = kvm_trap_emul_vm_init, .vcpu_init = kvm_trap_emul_vcpu_init,