From patchwork Wed Sep 24 20:43:36 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 393094 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 DF4F7140174 for ; Thu, 25 Sep 2014 06:43:59 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751650AbaIXUn5 (ORCPT ); Wed, 24 Sep 2014 16:43:57 -0400 Received: from cantor2.suse.de ([195.135.220.15]:47937 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753287AbaIXUnp (ORCPT ); Wed, 24 Sep 2014 16:43:45 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 07C3CADAB; Wed, 24 Sep 2014 20:43:39 +0000 (UTC) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: kvm@vger.kernel.org, pbonzini@redhat.com, Madhavan Srinivasan Subject: [PULL 22/24] powerpc/kvm: support to handle sw breakpoint Date: Wed, 24 Sep 2014 22:43:36 +0200 Message-Id: <1411591418-56061-23-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1411591418-56061-1-git-send-email-agraf@suse.de> References: <1411591418-56061-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org From: Madhavan Srinivasan This patch adds kernel side support for software breakpoint. Design is that, by using an illegal instruction, we trap to hypervisor via Emulation Assistance interrupt, where we check for the illegal instruction and accordingly we return to Host or Guest. Patch also adds support for software breakpoint in PR KVM. Signed-off-by: Madhavan Srinivasan Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_ppc.h | 6 ++++++ arch/powerpc/kvm/book3s.c | 3 ++- arch/powerpc/kvm/book3s_hv.c | 41 ++++++++++++++++++++++++++++++++++---- arch/powerpc/kvm/book3s_pr.c | 3 +++ arch/powerpc/kvm/emulate.c | 15 ++++++++++++++ 5 files changed, 63 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 73063ef..dbd160f 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -38,6 +38,12 @@ #include #endif +/* + * KVMPPC_INST_SW_BREAKPOINT is debug Instruction + * for supporting software breakpoint. + */ +#define KVMPPC_INST_SW_BREAKPOINT 0x00dddd00 + enum emulation_result { EMULATE_DONE, /* no further processing */ EMULATE_DO_MMIO, /* kvm_run filled with MMIO request */ diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c index f23b6a5..27d1b70 100644 --- a/arch/powerpc/kvm/book3s.c +++ b/arch/powerpc/kvm/book3s.c @@ -715,7 +715,8 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu, int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg) { - return -EINVAL; + vcpu->guest_debug = dbg->control; + return 0; } void kvmppc_decrementer_func(struct kvm_vcpu *vcpu) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 529d10a..e63587d 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -725,6 +725,30 @@ static int kvmppc_hcall_impl_hv(unsigned long cmd) return kvmppc_hcall_impl_hv_realmode(cmd); } +static int kvmppc_emulate_debug_inst(struct kvm_run *run, + struct kvm_vcpu *vcpu) +{ + u32 last_inst; + + if (kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst) != + EMULATE_DONE) { + /* + * Fetch failed, so return to guest and + * try executing it again. + */ + return RESUME_GUEST; + } + + if (last_inst == KVMPPC_INST_SW_BREAKPOINT) { + run->exit_reason = KVM_EXIT_DEBUG; + run->debug.arch.address = kvmppc_get_pc(vcpu); + return RESUME_HOST; + } else { + kvmppc_core_queue_program(vcpu, SRR1_PROGILL); + return RESUME_GUEST; + } +} + static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, struct task_struct *tsk) { @@ -807,12 +831,18 @@ static int kvmppc_handle_exit_hv(struct kvm_run *run, struct kvm_vcpu *vcpu, break; /* * This occurs if the guest executes an illegal instruction. - * We just generate a program interrupt to the guest, since - * we don't emulate any guest instructions at this stage. + * If the guest debug is disabled, generate a program interrupt + * to the guest. If guest debug is enabled, we need to check + * whether the instruction is a software breakpoint instruction. + * Accordingly return to Guest or Host. */ case BOOK3S_INTERRUPT_H_EMUL_ASSIST: - kvmppc_core_queue_program(vcpu, SRR1_PROGILL); - r = RESUME_GUEST; + if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) { + r = kvmppc_emulate_debug_inst(run, vcpu); + } else { + kvmppc_core_queue_program(vcpu, SRR1_PROGILL); + r = RESUME_GUEST; + } break; /* * This occurs if the guest (kernel or userspace), does something that @@ -924,6 +954,9 @@ static int kvmppc_get_one_reg_hv(struct kvm_vcpu *vcpu, u64 id, long int i; switch (id) { + case KVM_REG_PPC_DEBUG_INST: + *val = get_reg_val(id, KVMPPC_INST_SW_BREAKPOINT); + break; case KVM_REG_PPC_HIOR: *val = get_reg_val(id, 0); break; diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index faffb27..6d73708 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -1319,6 +1319,9 @@ static int kvmppc_get_one_reg_pr(struct kvm_vcpu *vcpu, u64 id, int r = 0; switch (id) { + case KVM_REG_PPC_DEBUG_INST: + *val = get_reg_val(id, KVMPPC_INST_SW_BREAKPOINT); + break; case KVM_REG_PPC_HIOR: *val = get_reg_val(id, to_book3s(vcpu)->hior); break; diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c index e96b50d..005222b 100644 --- a/arch/powerpc/kvm/emulate.c +++ b/arch/powerpc/kvm/emulate.c @@ -274,6 +274,21 @@ int kvmppc_emulate_instruction(struct kvm_run *run, struct kvm_vcpu *vcpu) } break; + case 0: + /* + * Instruction with primary opcode 0. Based on PowerISA + * these are illegal instructions. + */ + if (inst == KVMPPC_INST_SW_BREAKPOINT) { + run->exit_reason = KVM_EXIT_DEBUG; + run->debug.arch.address = kvmppc_get_pc(vcpu); + emulated = EMULATE_EXIT_USER; + advance = 0; + } else + emulated = EMULATE_FAIL; + + break; + default: emulated = EMULATE_FAIL; }