diff options
| author | Alex Bennée <alex.bennee@linaro.org> | 2017-11-23 12:11:34 +0000 |
|---|---|---|
| committer | Christoffer Dall <christoffer.dall@linaro.org> | 2017-11-29 18:17:47 +0100 |
| commit | e3feebf81744acd8b581e5eb58a93e8fdcf042a5 (patch) | |
| tree | 2abf6456d4edf1bf02b8cf1b60ea3095ec87aa1d /arch/arm64 | |
| parent | e70dce73befcf96607bc6e24c2c8f84229d6721e (diff) | |
kvm: arm64: handle single-step of hyp emulated mmio instructions
There is a fast-path of MMIO emulation inside hyp mode. The handling
of single-step is broadly the same as kvm_arm_handle_step_debug()
except we just setup ESR/HSR so handle_exit() does the correct thing
as we exit.
For the case of an emulated illegal access causing an SError we will
exit via the ARM_EXCEPTION_EL1_SERROR path in handle_exit(). We behave
as we would during a real SError and clear the DBG_SPSR_SS bit for the
emulated instruction.
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/kvm/hyp/switch.c | 37 |
1 files changed, 30 insertions, 7 deletions
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 */ |