diff options
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/debug.c | 21 | ||||
| -rw-r--r-- | arch/arm64/kvm/handle_exit.c | 57 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp-init.S | 1 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 37 |
4 files changed, 94 insertions, 22 deletions
diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c index dbadfaf850a7..fa63b28c65e0 100644 --- a/arch/arm64/kvm/debug.c +++ b/arch/arm64/kvm/debug.c @@ -221,3 +221,24 @@ void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) } } } + + +/* + * After successfully emulating an instruction, we might want to + * return to user space with a KVM_EXIT_DEBUG. We can only do this + * once the emulation is complete, though, so for userspace emulations + * we have to wait until we have re-entered KVM before calling this + * helper. + * + * Return true (and set exit_reason) to return to userspace or false + * if no further action is required. + */ +bool kvm_arm_handle_step_debug(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + run->exit_reason = KVM_EXIT_DEBUG; + run->debug.arch.hsr = ESR_ELx_EC_SOFTSTP_LOW << ESR_ELx_EC_SHIFT; + return true; + } + return false; +} diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index b71247995469..304203fa9e33 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -28,6 +28,7 @@ #include <asm/kvm_emulate.h> #include <asm/kvm_mmu.h> #include <asm/kvm_psci.h> +#include <asm/debug-monitors.h> #define CREATE_TRACE_POINTS #include "trace.h" @@ -187,14 +188,46 @@ static exit_handle_fn kvm_get_exit_handler(struct kvm_vcpu *vcpu) } /* + * We may be single-stepping an emulated instruction. If the emulation + * has been completed in the kernel, we can return to userspace with a + * KVM_EXIT_DEBUG, otherwise userspace needs to complete its + * emulation first. + */ +static int handle_trap_exceptions(struct kvm_vcpu *vcpu, struct kvm_run *run) +{ + int handled; + + /* + * See ARM ARM B1.14.1: "Hyp traps on instructions + * that fail their condition code check" + */ + if (!kvm_condition_valid(vcpu)) { + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + handled = 1; + } else { + exit_handle_fn exit_handler; + + exit_handler = kvm_get_exit_handler(vcpu); + handled = exit_handler(vcpu, run); + } + + /* + * kvm_arm_handle_step_debug() sets the exit_reason on the kvm_run + * structure if we need to return to userspace. + */ + if (handled > 0 && kvm_arm_handle_step_debug(vcpu, run)) + handled = 0; + + return handled; +} + +/* * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on * proper exit to userspace. */ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, int exception_index) { - exit_handle_fn exit_handler; - if (ARM_SERROR_PENDING(exception_index)) { u8 hsr_ec = ESR_ELx_EC(kvm_vcpu_get_hsr(vcpu)); @@ -220,20 +253,14 @@ int handle_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, return 1; case ARM_EXCEPTION_EL1_SERROR: kvm_inject_vabt(vcpu); - return 1; - case ARM_EXCEPTION_TRAP: - /* - * See ARM ARM B1.14.1: "Hyp traps on instructions - * that fail their condition code check" - */ - if (!kvm_condition_valid(vcpu)) { - kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + /* We may still need to return for single-step */ + if (!(*vcpu_cpsr(vcpu) & DBG_SPSR_SS) + && kvm_arm_handle_step_debug(vcpu, run)) + return 0; + else return 1; - } - - exit_handler = kvm_get_exit_handler(vcpu); - - return exit_handler(vcpu, run); + case ARM_EXCEPTION_TRAP: + return handle_trap_exceptions(vcpu, run); case ARM_EXCEPTION_HYP_GONE: /* * EL2 has been reset to the hyp-stub. This happens when a guest diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S index 3f9615582377..870828c364c5 100644 --- a/arch/arm64/kvm/hyp-init.S +++ b/arch/arm64/kvm/hyp-init.S @@ -151,6 +151,7 @@ reset: mrs x5, sctlr_el2 ldr x6, =SCTLR_ELx_FLAGS bic x5, x5, x6 // Clear SCTL_M and etc + pre_disable_mmu_workaround msr sctlr_el2, x5 isb diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 525c01f48867..f7c651f3a8c0 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -22,6 +22,7 @@ #include <asm/kvm_emulate.h> #include <asm/kvm_hyp.h> #include <asm/fpsimd.h> +#include <asm/debug-monitors.h> static bool __hyp_text __fpsimd_enabled_nvhe(void) { @@ -269,7 +270,11 @@ static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu) return true; } -static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu) +/* Skip an instruction which has been emulated. Returns true if + * execution can continue or false if we need to exit hyp mode because + * single-step was in effect. + */ +static bool __hyp_text __skip_instr(struct kvm_vcpu *vcpu) { *vcpu_pc(vcpu) = read_sysreg_el2(elr); @@ -282,6 +287,14 @@ static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu) } write_sysreg_el2(*vcpu_pc(vcpu), elr); + + if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) { + vcpu->arch.fault.esr_el2 = + (ESR_ELx_EC_SOFTSTP_LOW << ESR_ELx_EC_SHIFT) | 0x22; + return false; + } else { + return true; + } } int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) @@ -342,13 +355,21 @@ again: int ret = __vgic_v2_perform_cpuif_access(vcpu); if (ret == 1) { - __skip_instr(vcpu); - goto again; + if (__skip_instr(vcpu)) + goto again; + else + exit_code = ARM_EXCEPTION_TRAP; } if (ret == -1) { - /* Promote an illegal access to an SError */ - __skip_instr(vcpu); + /* Promote an illegal access to an + * SError. If we would be returning + * due to single-step clear the SS + * bit so handle_exit knows what to + * do after dealing with the error. + */ + if (!__skip_instr(vcpu)) + *vcpu_cpsr(vcpu) &= ~DBG_SPSR_SS; exit_code = ARM_EXCEPTION_EL1_SERROR; } @@ -363,8 +384,10 @@ again: int ret = __vgic_v3_perform_cpuif_access(vcpu); if (ret == 1) { - __skip_instr(vcpu); - goto again; + if (__skip_instr(vcpu)) + goto again; + else + exit_code = ARM_EXCEPTION_TRAP; } /* 0 falls through to be handled out of EL2 */ |