Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759344AbcCVOyX (ORCPT ); Tue, 22 Mar 2016 10:54:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57020 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757240AbcCVOx6 (ORCPT ); Tue, 22 Mar 2016 10:53:58 -0400 From: Laurent Vivier To: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org Cc: Gleb Natapov , Paolo Bonzini , Alexander Graf , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, dgibson@redhat.com, thuth@redhat.com, Laurent Vivier Subject: [PATCH] kvm-pr: manage single-step mode Date: Tue, 22 Mar 2016 15:53:48 +0100 Message-Id: <1458658428-19566-1-git-send-email-lvivier@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 22 Mar 2016 14:53:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2339 Lines: 80 Until now, when we connect gdb to the QEMU gdb-server, the single-step mode is not managed. This patch adds this, only for kvm-pr: If KVM_GUESTDBG_SINGLESTEP is set, we enable single-step trace bit in the MSR (MSR_SE) just before the __kvmppc_vcpu_run(), and disable it just after. In kvmppc_handle_exit_pr, instead of routing the interrupt to the guest, we return to host, with KVM_EXIT_DEBUG reason. Signed-off-by: Laurent Vivier --- arch/powerpc/kvm/book3s_pr.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 95bceca..e6896f4 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -882,6 +882,24 @@ void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr) } #endif +static void kvmppc_setup_debug(struct kvm_vcpu *vcpu) +{ + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + u64 msr = kvmppc_get_msr(vcpu); + + kvmppc_set_msr(vcpu, msr | MSR_SE); + } +} + +static void kvmppc_clear_debug(struct kvm_vcpu *vcpu) +{ + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + u64 msr = kvmppc_get_msr(vcpu); + + kvmppc_set_msr(vcpu, msr & ~MSR_SE); + } +} + int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, unsigned int exit_nr) { @@ -1208,8 +1226,13 @@ program_interrupt: #endif case BOOK3S_INTERRUPT_MACHINE_CHECK: case BOOK3S_INTERRUPT_TRACE: - kvmppc_book3s_queue_irqprio(vcpu, exit_nr); - r = RESUME_GUEST; + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + run->exit_reason = KVM_EXIT_DEBUG; + r = RESUME_HOST; + } else { + kvmppc_book3s_queue_irqprio(vcpu, exit_nr); + r = RESUME_GUEST; + } break; default: { @@ -1479,6 +1502,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) goto out; } + kvmppc_setup_debug(vcpu); + /* * Interrupts could be timers for the guest which we have to inject * again, so let's postpone them until we're in the guest and if we @@ -1501,6 +1526,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) ret = __kvmppc_vcpu_run(kvm_run, vcpu); + kvmppc_clear_debug(vcpu); + /* No need for kvm_guest_exit. It's done in handle_exit. We also get here with interrupts enabled. */ -- 2.5.0