Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752647AbbEFQYm (ORCPT ); Wed, 6 May 2015 12:24:42 -0400 Received: from static.88-198-71-155.clients.your-server.de ([88.198.71.155]:35247 "EHLO socrates.bennee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752311AbbEFQXa (ORCPT ); Wed, 6 May 2015 12:23:30 -0400 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 , Russell King , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v3 07/12] KVM: arm64: guest debug, add support for single-step Date: Wed, 6 May 2015 17:23:22 +0100 Message-Id: <1430929407-3487-8-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.3.5 In-Reply-To: <1430929407-3487-1-git-send-email-alex.bennee@linaro.org> References: <1430929407-3487-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5550 Lines: 180 This adds support for single-stepping the guest. To do this we need to manipulate the guests PSTATE.SS and MDSCR_EL1.SS bits which we do in the kvm_arm_setup/clear_debug() so we don't affect the apparent state of the guest. Additionally while the host is debugging the guest we suppress the ability of the guest to single-step itself. Signed-off-by: Alex Bennée --- v2 - Move pstate/mdscr manipulation into C - don't export guest_debug to assembly - add accessor for saved_debug regs - tweak save/restore of mdscr_el1 v3 - don't save PC in debug information struct - rename debug_saved_regs->guest_debug_state - save whole value, only use bits in restore - add save/restore_guest-debug_regs helper functions - simplify commit message for clarity - rm vcpu_debug_saved_reg access fn diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 064c105..9b3ed6d 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -302,7 +302,9 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) kvm_arm_set_running_vcpu(NULL); } -#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP) +#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE | \ + KVM_GUESTDBG_USE_SW_BP | \ + KVM_GUESTDBG_SINGLESTEP) /** * kvm_arch_vcpu_ioctl_set_guest_debug - set up guest debugging diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7cb99b5..b60fa7a 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -123,6 +123,12 @@ struct kvm_vcpu_arch { * here. */ + /* Guest registers we preserve during guest debugging */ + struct { + u32 pstate; + u32 mdscr_el1; + } guest_debug_state; + /* Don't run the guest */ bool pause; diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 5bee676..19346e8 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -19,11 +19,42 @@ #include +#include +#include #include +#include + +/* These are the bits of MDSCR_EL1 we may manipulate */ +#define MDSCR_EL1_DEBUG_MASK (DBG_MDSCR_SS | \ + DBG_MDSCR_KDE | \ + DBG_MDSCR_MDE) + +#define SPSR_DEBUG_MASK DBG_SPSR_SS static DEFINE_PER_CPU(u32, mdcr_el2); /** + * save/restore_guest_debug_regs + * + * For some debug operations we need to tweak some guest registers. As + * a result we need to save the state of those registers before we + * make those modifications. + */ +static void save_guest_debug_regs(struct kvm_vcpu *vcpu) +{ + vcpu->arch.guest_debug_state.pstate = *vcpu_cpsr(vcpu); + vcpu->arch.guest_debug_state.mdscr_el1 = vcpu_sys_reg(vcpu, MDSCR_EL1); +} + +static void restore_guest_debug_regs(struct kvm_vcpu *vcpu) +{ + *vcpu_cpsr(vcpu) |= + (vcpu->arch.guest_debug_state.pstate & SPSR_DEBUG_MASK); + vcpu_sys_reg(vcpu, MDSCR_EL1) |= + (vcpu->arch.guest_debug_state.mdscr_el1 & MDSCR_EL1_DEBUG_MASK); +} + +/** * kvm_arm_init_debug - grab what we need for debug * * Currently the sole task of this function is to retrieve the initial @@ -38,7 +69,6 @@ void kvm_arm_init_debug(void) __this_cpu_write(mdcr_el2, kvm_call_hyp(__kvm_get_mdcr_el2)); } - /** * kvm_arm_setup_debug - set up debug related stuff * @@ -75,15 +105,37 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) else vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDA; - /* Trap breakpoints? */ - if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP) + /* Is Guest debugging in effect? */ + if (vcpu->guest_debug) { vcpu->arch.mdcr_el2 |= MDCR_EL2_TDE; - else - vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; + /* Save guest debug state */ + save_guest_debug_regs(vcpu); + + /* + * Single Step (ARM ARM D2.12.3 The software step state + * machine) + * + * If we are doing Single Step we need to manipulate + * MDSCR_EL1.SS and PSTATE.SS. If not we need to + * suppress the guests ability to trigger single step itself. + */ + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + *vcpu_cpsr(vcpu) |= DBG_SPSR_SS; + vcpu_sys_reg(vcpu, MDSCR_EL1) |= DBG_MDSCR_SS; + } else { + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; + vcpu_sys_reg(vcpu, MDSCR_EL1) &= ~DBG_MDSCR_SS; + } + + } else { + /* Debug operations can go straight to the guest */ + vcpu->arch.mdcr_el2 &= ~MDCR_EL2_TDE; + } } void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) { - /* Nothing to do yet */ + if (vcpu->guest_debug) + restore_guest_debug_regs(vcpu); } diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 27f38a9..e9de13e 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -103,6 +103,7 @@ static int kvm_handle_guest_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) run->debug.arch.hsr = hsr; switch (hsr >> ESR_ELx_EC_SHIFT) { + case ESR_ELx_EC_SOFTSTP_LOW: case ESR_ELx_EC_BKPT32: case ESR_ELx_EC_BRK64: break; @@ -130,6 +131,7 @@ 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_SOFTSTP_LOW]= kvm_handle_guest_debug, [ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug, [ESR_ELx_EC_BRK64] = kvm_handle_guest_debug, }; -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/