From patchwork Tue Feb 23 14:27:55 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 81461 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o1NESJKX027657 for ; Tue, 23 Feb 2010 14:28:19 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752716Ab0BWO2R (ORCPT ); Tue, 23 Feb 2010 09:28:17 -0500 Received: from david.siemens.de ([192.35.17.14]:18233 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524Ab0BWO2Q (ORCPT ); Tue, 23 Feb 2010 09:28:16 -0500 Received: from mail3.siemens.de (localhost [127.0.0.1]) by david.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o1NERuoK004893; Tue, 23 Feb 2010 15:27:56 +0100 Received: from [139.25.109.167] (mchn012c.ww002.siemens.net [139.25.109.167] (may be forged)) by mail3.siemens.de (8.12.11.20060308/8.12.11) with ESMTP id o1NERtuP015355; Tue, 23 Feb 2010 15:27:56 +0100 Message-ID: <4B83E5EB.7080702@siemens.com> Date: Tue, 23 Feb 2010 15:27:55 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Avi Kivity , Marcelo Tosatti CC: kvm , qemu-devel Subject: [PATCH][uq/master] KVM: Rework of guest debug state writing Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Tue, 23 Feb 2010 14:28:20 +0000 (UTC) diff --git a/kvm-all.c b/kvm-all.c index 1a02076..2f7e33a 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -65,6 +65,7 @@ struct KVMState int broken_set_mem_region; int migration_log; int vcpu_events; + int robust_singlestep; #ifdef KVM_CAP_SET_GUEST_DEBUG struct kvm_sw_breakpoint_head kvm_sw_breakpoints; #endif @@ -659,6 +660,12 @@ int kvm_init(int smp_cpus) s->vcpu_events = kvm_check_extension(s, KVM_CAP_VCPU_EVENTS); #endif + s->robust_singlestep = 0; +#ifdef KVM_CAP_X86_ROBUST_SINGLESTEP + s->robust_singlestep = + kvm_check_extension(s, KVM_CAP_X86_ROBUST_SINGLESTEP); +#endif + ret = kvm_arch_init(s, smp_cpus); if (ret < 0) goto err; @@ -917,6 +924,11 @@ int kvm_has_vcpu_events(void) return kvm_state->vcpu_events; } +int kvm_has_robust_singlestep(void) +{ + return kvm_state->robust_singlestep; +} + void kvm_setup_guest_memory(void *start, size_t size) { if (!kvm_has_sync_mmu()) { @@ -974,10 +986,6 @@ static void kvm_invoke_set_guest_debug(void *data) struct kvm_set_guest_debug_data *dbg_data = data; CPUState *env = dbg_data->env; - if (env->kvm_vcpu_dirty) { - kvm_arch_put_registers(env); - env->kvm_vcpu_dirty = 0; - } dbg_data->err = kvm_vcpu_ioctl(env, KVM_SET_GUEST_DEBUG, &dbg_data->dbg); } @@ -985,12 +993,12 @@ int kvm_update_guest_debug(CPUState *env, unsigned long reinject_trap) { struct kvm_set_guest_debug_data data; - data.dbg.control = 0; - if (env->singlestep_enabled) - data.dbg.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP; + data.dbg.control = reinject_trap; + if (env->singlestep_enabled) { + data.dbg.control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP; + } kvm_arch_update_guest_debug(env, &data.dbg); - data.dbg.control |= reinject_trap; data.env = env; on_vcpu(env, kvm_invoke_set_guest_debug, &data); diff --git a/kvm.h b/kvm.h index 9a9cdd5..976812c 100644 --- a/kvm.h +++ b/kvm.h @@ -40,6 +40,7 @@ int kvm_log_stop(target_phys_addr_t phys_addr, ram_addr_t size); int kvm_has_sync_mmu(void); int kvm_has_vcpu_events(void); +int kvm_has_robust_singlestep(void); void kvm_setup_guest_memory(void *start, size_t size); diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 5d9aecc..78096d7 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -843,6 +843,37 @@ static int kvm_get_vcpu_events(CPUState *env) return 0; } +static int kvm_guest_debug_workarounds(CPUState *env) +{ + int ret = 0; +#ifdef KVM_CAP_SET_GUEST_DEBUG + unsigned long reinject_trap = 0; + + if (!kvm_has_vcpu_events()) { + if (env->exception_injected == 1) { + reinject_trap = KVM_GUESTDBG_INJECT_DB; + } else if (env->exception_injected == 3) { + reinject_trap = KVM_GUESTDBG_INJECT_BP; + } + env->exception_injected = -1; + } + + /* + * Kernels before KVM_CAP_X86_ROBUST_SINGLESTEP overwrote flags.TF + * injected via SET_GUEST_DEBUG while updating GP regs. Work around this + * by updating the debug state once again if single-stepping is on. + * Another reason to call kvm_update_guest_debug here is a pending debug + * trap raise by the guest. On kernels without SET_VCPU_EVENTS we have to + * reinject them via SET_GUEST_DEBUG. + */ + if (reinject_trap || + (!kvm_has_robust_singlestep() && env->singlestep_enabled)) { + ret = kvm_update_guest_debug(env, reinject_trap); + } +#endif /* KVM_CAP_SET_GUEST_DEBUG */ + return ret; +} + int kvm_arch_put_registers(CPUState *env) { int ret; @@ -871,6 +902,11 @@ int kvm_arch_put_registers(CPUState *env) if (ret < 0) return ret; + /* must be last */ + ret = kvm_guest_debug_workarounds(env); + if (ret < 0) + return ret; + return 0; } @@ -1114,10 +1150,13 @@ int kvm_arch_debug(struct kvm_debug_exit_arch *arch_info) } else if (kvm_find_sw_breakpoint(cpu_single_env, arch_info->pc)) handle = 1; - if (!handle) - kvm_update_guest_debug(cpu_single_env, - (arch_info->exception == 1) ? - KVM_GUESTDBG_INJECT_DB : KVM_GUESTDBG_INJECT_BP); + if (!handle) { + cpu_synchronize_state(cpu_single_env); + assert(cpu_single_env->exception_injected == -1); + + cpu_single_env->exception_injected = arch_info->exception; + cpu_single_env->has_error_code = 0; + } return handle; }