From patchwork Tue Mar 31 15:08:04 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 6131061 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id CB521BF4A6 for ; Tue, 31 Mar 2015 15:17:05 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DF7BA2011E for ; Tue, 31 Mar 2015 15:17:04 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9786F200F4 for ; Tue, 31 Mar 2015 15:17:03 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ycxq9-00007C-27; Tue, 31 Mar 2015 15:12:29 +0000 Received: from merlin.infradead.org ([2001:4978:20e::2]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ycxn4-0005s9-6M for linux-arm-kernel@bombadil.infradead.org; Tue, 31 Mar 2015 15:09:18 +0000 Received: from static.88-198-71-155.clients.your-server.de ([88.198.71.155] helo=socrates.bennee.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ycxn1-00008O-AG for linux-arm-kernel@lists.infradead.org; Tue, 31 Mar 2015 15:09:15 +0000 Received: from localhost ([127.0.0.1] helo=zen.linaroharston) by socrates.bennee.com with esmtp (Exim 4.80) (envelope-from ) id 1YcysV-0005gI-BW; Tue, 31 Mar 2015 18:18:59 +0200 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 Subject: [PATCH v2 06/10] KVM: arm64: guest debug, add SW break point support Date: Tue, 31 Mar 2015 16:08:04 +0100 Message-Id: <1427814488-28467-7-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.3.4 In-Reply-To: <1427814488-28467-1-git-send-email-alex.bennee@linaro.org> References: <1427814488-28467-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 127.0.0.1 X-SA-Exim-Mail-From: alex.bennee@linaro.org X-SA-Exim-Scanned: No (on socrates.bennee.com); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150331_110915_471826_65C5D8C9 X-CRM114-Status: GOOD ( 15.34 ) X-Spam-Score: -1.2 (-) Cc: Russell King , Jonathan Corbet , Gleb Natapov , jan.kiszka@siemens.com, "open list:DOCUMENTATION" , Will Deacon , open list , dahi@linux.vnet.ibm.com, Catalin Marinas , r65777@freescale.com, bp@suse.de, =?UTF-8?q?Alex=20Benn=C3=A9e?= X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This adds support for SW breakpoints inserted by userspace. We do this by trapping all BKPT exceptions in the hypervisor (MDCR_EL2_TDE). The kvm_debug_exit_arch carries the address of the exception. If user-space doesn't know of the breakpoint then we have a guest inserted breakpoint and the hypervisor needs to start again and deliver the exception to guest. Signed-off-by: Alex Bennée Reviewed-by: Andrew Jones --- v2 - update to use new exit struct - tweak for C setup - do our setup in debug_setup/clear code - fixed up comments diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 06c5064..17d4f9c 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2626,7 +2626,7 @@ 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/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 7ea8b0e..d3bc8dc 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -304,7 +304,7 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_arm_set_running_vcpu(NULL); } -#define KVM_GUESTDBG_VALID (KVM_GUESTDBG_ENABLE) +#define KVM_GUESTDBG_VALID (KVM_GUESTDBG_ENABLE|KVM_GUESTDBG_USE_SW_BP) int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu, struct kvm_guest_debug *dbg) diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 8a29d0b..cff0475 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -45,11 +45,18 @@ void kvm_arch_setup_debug(struct kvm_vcpu *vcpu) vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | MDCR_EL2_TPMCR); vcpu->arch.mdcr_el2 |= (MDCR_EL2_TDRA | MDCR_EL2_TDOSA); + /* Trap debug register access? */ if (!vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; else 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; + else + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; + } void kvm_arch_clear_debug(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 524fa25..ed1bbb4 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -82,6 +82,37 @@ static int kvm_handle_wfx(struct kvm_vcpu *vcpu, struct kvm_run *run) return 1; } +/** + * kvm_handle_debug_exception - 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 as we + * just need to report the PC and the HSR values to userspace. + * Userspace may decide to re-inject the exception and deliver it to + * the guest if it wasn't for the host to deal with. + */ +static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + u32 hsr = kvm_vcpu_get_hsr(vcpu); + + 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: + run->debug.arch.pc = *vcpu_pc(vcpu); + break; + default: + kvm_err("%s: un-handled case hsr: %#08x\n", + __func__, (unsigned int) hsr); + break; + } + return 0; +} + 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 +127,8 @@ 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)