| /* |
| * Debug and Guest Debug support |
| * |
| * Copyright (C) 2015 - Linaro Ltd |
| * Author: Alex Bennée <alex.bennee@linaro.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include <linux/kvm_host.h> |
| |
| #include <asm/kvm_arm.h> |
| |
| static DEFINE_PER_CPU(u32, mdcr_el2); |
| |
| /** |
| * kvm_arm_init_debug - grab what we need for debug |
| * |
| * Currently the sole task of this function is to retrieve the initial |
| * value of mdcr_el2 so we can preserve MDCR_EL2.HPMN which has |
| * presumably been set-up by some knowledgeable bootcode. |
| * |
| * It is called once per-cpu during CPU hyp initialisation. |
| */ |
| |
| 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 |
| * |
| * @vcpu: the vcpu pointer |
| * |
| * This is called before each entry into the hypervisor to setup any |
| * debug related registers. Currently this just ensures we will trap |
| * access to: |
| * - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR) |
| * - Debug ROM Address (MDCR_EL2_TDRA) |
| * - OS related registers (MDCR_EL2_TDOSA) |
| * |
| * Additionally, KVM only traps guest accesses to the debug registers if |
| * the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY |
| * flag on vcpu->arch.debug_flags). Since the guest must not interfere |
| * with the hardware state when debugging the guest, we must ensure that |
| * trapping is enabled whenever we are debugging the guest using the |
| * debug registers. |
| */ |
| |
| void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) |
| { |
| bool trap_debug = !(vcpu->arch.debug_flags & KVM_ARM64_DEBUG_DIRTY); |
| |
| vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK; |
| vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | |
| MDCR_EL2_TPMCR | |
| MDCR_EL2_TDRA | |
| MDCR_EL2_TDOSA); |
| |
| /* Trap on access to debug registers? */ |
| 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) |
| { |
| /* Nothing to do yet */ |
| } |