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[209.132.180.67]) by mx.google.com with ESMTP id e3si4749017pdc.50.2015.07.01.11.30.24; Wed, 01 Jul 2015 11:30:24 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753664AbbGASaN (ORCPT + 29 others); Wed, 1 Jul 2015 14:30:13 -0400 Received: from mail-wg0-f44.google.com ([74.125.82.44]:35225 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753027AbbGAS3Y (ORCPT ); Wed, 1 Jul 2015 14:29:24 -0400 Received: by wgjx7 with SMTP id x7so43912541wgj.2 for ; Wed, 01 Jul 2015 11:29:22 -0700 (PDT) X-Received: by 10.194.110.100 with SMTP id hz4mr51710562wjb.6.1435775362116; Wed, 01 Jul 2015 11:29:22 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by mx.google.com with ESMTPSA id ny7sm23245558wic.11.2015.07.01.11.29.19 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 01 Jul 2015 11:29:20 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 15FC73E1066; Wed, 1 Jul 2015 19:29:18 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org, marc.zyngier@arm.com, peter.maydell@linaro.org, agraf@suse.de, drjones@redhat.com, pbonzini@redhat.com, zhichao.huang@linaro.org Cc: jan.kiszka@siemens.com, dahi@linux.vnet.ibm.com, r65777@freescale.com, bp@suse.de, =?UTF-8?q?Alex=20Benn=C3=A9e?= , Gleb Natapov , Jonathan Corbet , Catalin Marinas , Will Deacon , linux-doc@vger.kernel.org (open list:DOCUMENTATION), linux-kernel@vger.kernel.org (open list) Subject: [PATCH v7 05/11] KVM: arm64: guest debug, add SW break point support Date: Wed, 1 Jul 2015 19:28:57 +0100 Message-Id: <1435775343-20034-6-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.4.5 In-Reply-To: <1435775343-20034-1-git-send-email-alex.bennee@linaro.org> References: <1435775343-20034-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: list List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: alex.bennee@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.217.173 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , This adds support for SW breakpoints inserted by userspace. We do this by trapping all guest software debug exceptions to the hypervisor (MDCR_EL2.TDE). The exit handler sets an exit reason of KVM_EXIT_DEBUG with the kvm_debug_exit_arch structure holding the exception syndrome information. It will be up to userspace to extract the PC (via GET_ONE_REG) and determine if the debug event was for a breakpoint it inserted. If not userspace will need to re-inject the correct exception restart the hypervisor to deliver the debug exception to the guest. Any other guest software debug exception (e.g. single step or HW assisted breakpoints) will cause an error and the VM to be killed. This is addressed by later patches which add support for the other debug types. Signed-off-by: Alex Bennée Reviewed-by: Christoffer Dall --- v2 - update to use new exit struct - tweak for C setup - do our setup in debug_setup/clear code - fixed up comments v3: - fix spacing in KVM_GUESTDBG_VALID_MASK - fix and clarify wording on kvm_handle_guest_debug - handle error case in kvm_handle_guest_debug - re-word the commit message v4 - rm else leg - add r-b-tag v7 - moved ioctl to guest --- Documentation/virtual/kvm/api.txt | 2 +- arch/arm64/kvm/debug.c | 3 +++ arch/arm64/kvm/guest.c | 2 +- arch/arm64/kvm/handle_exit.c | 36 ++++++++++++++++++++++++++++++++++++ 4 files changed, 41 insertions(+), 2 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index ba635c7..33c8143 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2667,7 +2667,7 @@ when running. Common control bits are: The top 16 bits of the control field are architecture specific control flags which can include the following: - - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86] + - KVM_GUESTDBG_USE_SW_BP: using software breakpoints [x86, arm64] - KVM_GUESTDBG_USE_HW_BP: using hardware breakpoints [x86, s390] - KVM_GUESTDBG_INJECT_DB: inject DB type exception [x86] - KVM_GUESTDBG_INJECT_BP: inject BP type exception [x86] diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index faf0e1f..8d1bfa4 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -73,6 +73,9 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) if (trap_debug) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; + /* Trap breakpoints? */ + if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) + vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; } void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 0ba8677..22d22c5 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -332,7 +332,7 @@ int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu, return -EINVAL; } -#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE) +#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP) /** * kvm_arch_vcpu_ioctl_set_guest_debug - set up guest debugging diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 524fa25..27f38a9 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -82,6 +82,40 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) return 1; } +/** + * kvm_handle_guest_debug - handle a debug exception instruction + * + * @vcpu: the vcpu pointer + * @run: access to the kvm_run structure for results + * + * We route all debug exceptions through the same handler. If both the + * guest and host are using the same debug facilities it will be up to + * userspace to re-inject the correct exception for guest delivery. + * + * @return: 0 (while setting run->exit_reason), -1 for error + */ +static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + int ret = 0; + + run->exit_reason = KVM_EXIT_DEBUG; + run->debug.arch.hsr = hsr; + + switch (hsr >> ESR_ELx_EC_SHIFT) { + case ESR_ELx_EC_BKPT32: + case ESR_ELx_EC_BRK64: + break; + default: + kvm_err("%s: un-handled case hsr: %#08x\n", + __func__, (unsigned int) hsr); + ret = -1; + break; + } + + return ret; +} + static exit_handle_fn arm_exit_handlers[] = { [ESR_ELx_EC_WFx] = kvm_handle_wfx, [ESR_ELx_EC_CP15_32] = kvm_handle_cp15_32, @@ -96,6 +130,8 @@ static exit_handle_fn arm_exit_handlers[] = { [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, + [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, + [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, }; static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu)