From patchwork Wed Jan 13 07:08:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aravinda Prasad X-Patchwork-Id: 566829 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 9FB98140BA4 for ; Wed, 13 Jan 2016 18:08:19 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755150AbcAMHIS (ORCPT ); Wed, 13 Jan 2016 02:08:18 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:46101 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755035AbcAMHIS (ORCPT ); Wed, 13 Jan 2016 02:08:18 -0500 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Wed, 13 Jan 2016 00:08:15 -0700 X-IBM-Helo: d03dlp02.boulder.ibm.com X-IBM-MailFrom: aravinda@linux.vnet.ibm.com X-IBM-RcptTo: kvm-ppc@vger.kernel.org;kvm@vger.kernel.org Received: from b03cxnp08025.gho.boulder.ibm.com (b03cxnp08025.gho.boulder.ibm.com [9.17.130.17]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id ED38C3E40062; Wed, 13 Jan 2016 00:08:14 -0700 (MST) Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by b03cxnp08025.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u0D78Edj28836044; Wed, 13 Jan 2016 00:08:14 -0700 Received: from d03av01.boulder.ibm.com (localhost [127.0.0.1]) by d03av01.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u0D78D7O014043; Wed, 13 Jan 2016 00:08:14 -0700 Received: from [127.0.1.1] (aravindap.in.ibm.com [9.124.35.86]) by d03av01.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id u0D78ANC013845; Wed, 13 Jan 2016 00:08:10 -0700 Subject: [PATCH v3 2/2] KVM: PPC: Exit guest upon MCE when FWNMI capability is enabled To: gleb@kernel.org, agraf@suse.de, kvm-ppc@vger.kernel.org, paulus@ozlabs.org, linuxppc-dev@ozlabs.org, pbonzini@redhat.com From: Aravinda Prasad Cc: mahesh@linux.vnet.ibm.com, david@gibson.dropbear.id.au, kvm@vger.kernel.org, mpe@ellerman.id.au Date: Wed, 13 Jan 2016 12:38:09 +0530 Message-ID: <20160113070809.20248.80811.stgit@aravindap> In-Reply-To: <20160113070759.20248.86252.stgit@aravindap> References: <20160113070759.20248.86252.stgit@aravindap> User-Agent: StGit/0.15 MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16011307-0009-0000-0000-0000115CC9CF Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Enhance KVM to cause a guest exit with KVM_EXIT_NMI exit reasons upon a machine check exception (MCE) in the guest address space if the KVM_CAP_PPC_FWNMI capability is enabled (instead of delivering 0x200 interrupt to guest). This enables QEMU to build error log and deliver machine check exception to guest via guest registered machine check handler. This approach simplifies the delivering of machine check exception to guest OS compared to the earlier approach of KVM directly invoking 0x200 guest interrupt vector. In the earlier approach QEMU was enhanced to patch the 0x200 interrupt vector during boot. The patched code at 0x200 issued a private hcall to pass the control to QEMU to build the error log. This design/approach is based on the feedback for the QEMU patches to handle machine check exception. Details of earlier approach of handling machine check exception in QEMU and related discussions can be found at: https://lists.nongnu.org/archive/html/qemu-devel/2014-11/msg00813.html Signed-off-by: Aravinda Prasad Reviewed-by: David Gibson --- arch/powerpc/kvm/book3s_hv.c | 12 ++------ arch/powerpc/kvm/book3s_hv_rmhandlers.S | 48 +++++++++++++++---------------- 2 files changed, 26 insertions(+), 34 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" 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/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index a7352b5..4fa03d0 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -858,15 +858,9 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, r = RESUME_GUEST; break; case BOOK3S_INTERRUPT_MACHINE_CHECK: - /* - * Deliver a machine check interrupt to the guest. - * We have to do this, even if the host has handled the - * machine check, because machine checks use SRR0/1 and - * the interrupt might have trashed guest state in them. - */ - kvmppc_book3s_queue_irqprio(vcpu, - BOOK3S_INTERRUPT_MACHINE_CHECK); - r = RESUME_GUEST; + /* Exit to guest with KVM_EXIT_NMI as exit reason */ + run->exit_reason = KVM_EXIT_NMI; + r = RESUME_HOST; break; case BOOK3S_INTERRUPT_PROGRAM: { diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S index 3c6badc..84e32a3 100644 --- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S @@ -133,21 +133,18 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) stb r0, HSTATE_HWTHREAD_REQ(r13) /* - * For external and machine check interrupts, we need - * to call the Linux handler to process the interrupt. - * We do that by jumping to absolute address 0x500 for - * external interrupts, or the machine_check_fwnmi label - * for machine checks (since firmware might have patched - * the vector area at 0x200). The [h]rfid at the end of the - * handler will return to the book3s_hv_interrupts.S code. - * For other interrupts we do the rfid to get back - * to the book3s_hv_interrupts.S code here. + * For external interrupts we need to call the Linux + * handler to process the interrupt. We do that by jumping + * to absolute address 0x500 for external interrupts. + * The [h]rfid at the end of the handler will return to + * the book3s_hv_interrupts.S code. For other interrupts + * we do the rfid to get back to the book3s_hv_interrupts.S + * code here. */ ld r8, 112+PPC_LR_STKOFF(r1) addi r1, r1, 112 ld r7, HSTATE_HOST_MSR(r13) - cmpwi cr1, r12, BOOK3S_INTERRUPT_MACHINE_CHECK cmpwi r12, BOOK3S_INTERRUPT_EXTERNAL beq 11f cmpwi r12, BOOK3S_INTERRUPT_H_DOORBELL @@ -162,7 +159,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) mtmsrd r6, 1 /* Clear RI in MSR */ mtsrr0 r8 mtsrr1 r7 - beq cr1, 13f /* machine check */ RFI /* On POWER7, we have external interrupts set to use HSRR0/1 */ @@ -170,8 +166,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S) mtspr SPRN_HSRR1, r7 ba 0x500 -13: b machine_check_fwnmi - 14: mtspr SPRN_HSRR0, r8 mtspr SPRN_HSRR1, r7 b hmi_exception_after_realmode @@ -2390,15 +2384,13 @@ machine_check_realmode: ld r9, HSTATE_KVM_VCPU(r13) li r12, BOOK3S_INTERRUPT_MACHINE_CHECK /* - * Deliver unhandled/fatal (e.g. UE) MCE errors to guest through - * machine check interrupt (set HSRR0 to 0x200). And for handled - * errors (no-fatal), just go back to guest execution with current - * HSRR0 instead of exiting guest. This new approach will inject - * machine check to guest for fatal error causing guest to crash. - * - * The old code used to return to host for unhandled errors which - * was causing guest to hang with soft lockups inside guest and - * makes it difficult to recover guest instance. + * Deliver unhandled/fatal (e.g. UE) MCE errors to guest either + * through machine check interrupt (set HSRR0 to 0x200) or by + * exiting the guest with KVM_EXIT_NMI exit reason if guest is + * FWNMI capable. For handled errors (no-fatal), just go back + * to guest execution with current HSRR0. This new approach + * injects machine check errors in guest address space to guest + * enabling guest kernel to suitably handle such errors. * * if we receive machine check with MSR(RI=0) then deliver it to * guest as machine check causing guest to crash. @@ -2408,11 +2400,17 @@ machine_check_realmode: beq 1f /* Deliver a machine check to guest */ ld r10, VCPU_PC(r9) cmpdi r3, 0 /* Did we handle MCE ? */ - bne 2f /* Continue guest execution. */ + bne 3f /* Continue guest execution. */ /* If not, deliver a machine check. SRR0/1 are already set */ -1: li r10, BOOK3S_INTERRUPT_MACHINE_CHECK +1: /* Check if guest is capable of handling NMI exit */ + ld r3, VCPU_KVM(r9) + lbz r3, KVM_FWNMI(r3) + cmpdi r3, 1 /* FWNMI capable? */ + bne 2f + b mc_cont +2: li r10, BOOK3S_INTERRUPT_MACHINE_CHECK bl kvmppc_msr_interrupt -2: b fast_interrupt_c_return +3: b fast_interrupt_c_return /* * Check the reason we woke from nap, and take appropriate action.