diff options
Diffstat (limited to 'arch/arm64/kvm/debug.c')
| -rw-r--r-- | arch/arm64/kvm/debug.c | 70 |
1 files changed, 51 insertions, 19 deletions
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index 4fd5c216c4bb..ce8886122ed3 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -23,7 +23,7 @@ static DEFINE_PER_CPU(u64, mdcr_el2); -/** +/* * save/restore_guest_debug_regs * * For some debug operations we need to tweak some guest registers. As @@ -32,6 +32,10 @@ static DEFINE_PER_CPU(u64, mdcr_el2); * * Guest access to MDSCR_EL1 is trapped by the hypervisor and handled * after we have restored the preserved value to the main context. + * + * When single-step is enabled by userspace, we tweak PSTATE.SS on every + * guest entry. Preserve PSTATE.SS so we can restore the original value + * for the vcpu after the single-step is disabled. */ static void save_guest_debug_regs(struct kvm_vcpu *vcpu) { @@ -41,6 +45,9 @@ static void save_guest_debug_regs(struct kvm_vcpu *vcpu) trace_kvm_arm_set_dreg32("Saved MDSCR_EL1", vcpu->arch.guest_debug_preserved.mdscr_el1); + + vcpu->arch.guest_debug_preserved.pstate_ss = + (*vcpu_cpsr(vcpu) & DBG_SPSR_SS); } static void restore_guest_debug_regs(struct kvm_vcpu *vcpu) @@ -51,6 +58,11 @@ static void restore_guest_debug_regs(struct kvm_vcpu *vcpu) trace_kvm_arm_set_dreg32("Restored MDSCR_EL1", vcpu_read_sys_reg(vcpu, MDSCR_EL1)); + + if (vcpu->arch.guest_debug_preserved.pstate_ss) + *vcpu_cpsr(vcpu) |= DBG_SPSR_SS; + else + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; } /** @@ -104,11 +116,11 @@ static void kvm_arm_setup_mdcr_el2(struct kvm_vcpu *vcpu) * Trap debug register access when one of the following is true: * - Userspace is using the hardware to debug the guest * (KVM_GUESTDBG_USE_HW is set). - * - The guest is not using debug (KVM_ARM64_DEBUG_DIRTY is clear). + * - The guest is not using debug (DEBUG_DIRTY clear). * - The guest has enabled the OS Lock (debug exceptions are blocked). */ if ((vcpu->guest_debug & KVM_GUESTDBG_USE_HW) || - !(vcpu->arch.flags & KVM_ARM64_DEBUG_DIRTY) || + !vcpu_get_flag(vcpu, DEBUG_DIRTY) || kvm_vcpu_os_lock_enabled(vcpu)) vcpu->arch.mdcr_el2 |= MDCR_EL2_TDA; @@ -131,6 +143,7 @@ void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu) /** * kvm_arm_reset_debug_ptr - reset the debug ptr to point to the vcpu state + * @vcpu: the vcpu pointer */ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) @@ -147,8 +160,8 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) * debug related registers. * * 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.flags). Since the guest must not interfere + * the guest is not actively using them (see the DEBUG_DIRTY + * flag on vcpu->arch.iflags). 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. @@ -188,7 +201,18 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) * debugging the system. */ if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { - *vcpu_cpsr(vcpu) |= DBG_SPSR_SS; + /* + * If the software step state at the last guest exit + * was Active-pending, we don't set DBG_SPSR_SS so + * that the state is maintained (to not run another + * single-step until the pending Software Step + * exception is taken). + */ + if (!vcpu_get_flag(vcpu, DBG_SS_ACTIVE_PENDING)) + *vcpu_cpsr(vcpu) |= DBG_SPSR_SS; + else + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; + mdscr = vcpu_read_sys_reg(vcpu, MDSCR_EL1); mdscr |= DBG_MDSCR_SS; vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1); @@ -205,9 +229,8 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) * * We simply switch the debug_ptr to point to our new * external_debug_state which has been populated by the - * debug ioctl. The existing KVM_ARM64_DEBUG_DIRTY - * mechanism ensures the registers are updated on the - * world switch. + * debug ioctl. The existing DEBUG_DIRTY mechanism ensures + * the registers are updated on the world switch. */ if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) { /* Enable breakpoints/watchpoints */ @@ -216,7 +239,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) vcpu_write_sys_reg(vcpu, mdscr, MDSCR_EL1); vcpu->arch.debug_ptr = &vcpu->arch.external_debug_state; - vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY; + vcpu_set_flag(vcpu, DEBUG_DIRTY); trace_kvm_arm_set_regset("BKPTS", get_num_brps(), &vcpu->arch.debug_ptr->dbg_bcr[0], @@ -246,7 +269,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) /* If KDE or MDE are set, perform a full save/restore cycle. */ if (vcpu_read_sys_reg(vcpu, MDSCR_EL1) & (DBG_MDSCR_KDE | DBG_MDSCR_MDE)) - vcpu->arch.flags |= KVM_ARM64_DEBUG_DIRTY; + vcpu_set_flag(vcpu, DEBUG_DIRTY); /* Write mdcr_el2 changes since vcpu_load on VHE systems */ if (has_vhe() && orig_mdcr_el2 != vcpu->arch.mdcr_el2) @@ -263,6 +286,15 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) * Restore the guest's debug registers if we were using them. */ if (vcpu->guest_debug || kvm_vcpu_os_lock_enabled(vcpu)) { + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS)) + /* + * Mark the vcpu as ACTIVE_PENDING + * until Software Step exception is taken. + */ + vcpu_set_flag(vcpu, DBG_SS_ACTIVE_PENDING); + } + restore_guest_debug_regs(vcpu); /* @@ -296,18 +328,18 @@ void kvm_arch_vcpu_load_debug_state_flags(struct kvm_vcpu *vcpu) * If SPE is present on this CPU and is available at current EL, * we may need to check if the host state needs to be saved. */ - if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_PMSVER_SHIFT) && - !(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(SYS_PMBIDR_EL1_P_SHIFT))) - vcpu->arch.flags |= KVM_ARM64_DEBUG_STATE_SAVE_SPE; + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_PMSVer_SHIFT) && + !(read_sysreg_s(SYS_PMBIDR_EL1) & BIT(PMBIDR_EL1_P_SHIFT))) + vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_SPE); /* Check if we have TRBE implemented and available at the host */ - if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_TRBE_SHIFT) && - !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_PROG)) - vcpu->arch.flags |= KVM_ARM64_DEBUG_STATE_SAVE_TRBE; + if (cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceBuffer_SHIFT) && + !(read_sysreg_s(SYS_TRBIDR_EL1) & TRBIDR_EL1_P)) + vcpu_set_flag(vcpu, DEBUG_STATE_SAVE_TRBE); } void kvm_arch_vcpu_put_debug_state_flags(struct kvm_vcpu *vcpu) { - vcpu->arch.flags &= ~(KVM_ARM64_DEBUG_STATE_SAVE_SPE | - KVM_ARM64_DEBUG_STATE_SAVE_TRBE); + vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_SPE); + vcpu_clear_flag(vcpu, DEBUG_STATE_SAVE_TRBE); } |