diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 152049c5055d..14b747266607 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -337,12 +337,6 @@ void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) preempt_enable(); } -#define __ptrauth_save_key(regs, key) \ -({ \ - regs[key ## KEYLO_EL1] = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \ - regs[key ## KEYHI_EL1] = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \ -}) - void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { int *last_ran; @@ -376,17 +370,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) else vcpu_set_wfx_traps(vcpu); - if (vcpu_has_ptrauth(vcpu)) { - struct kvm_cpu_context *ctxt = vcpu->arch.host_cpu_context; - - __ptrauth_save_key(ctxt->sys_regs, APIA); - __ptrauth_save_key(ctxt->sys_regs, APIB); - __ptrauth_save_key(ctxt->sys_regs, APDA); - __ptrauth_save_key(ctxt->sys_regs, APDB); - __ptrauth_save_key(ctxt->sys_regs, APGA); - + if (vcpu_has_ptrauth(vcpu)) vcpu_ptrauth_disable(vcpu); - } } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index 065251efa2e6..5a02d4c90559 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -162,25 +162,14 @@ static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) return 1; } -/* - * Handle the guest trying to use a ptrauth instruction, or trying to access a - * ptrauth register. - */ -void kvm_arm_vcpu_ptrauth_trap(struct kvm_vcpu *vcpu) -{ - if (vcpu_has_ptrauth(vcpu)) - vcpu_ptrauth_enable(vcpu); - else - kvm_inject_undefined(vcpu); -} - /* * Guest usage of a ptrauth instruction (which the guest EL1 did not turn into - * a NOP). + * a NOP). If we get here, it is that we didn't fixup ptrauth on exit, and all + * that we can do is give the guest an UNDEF. */ static int kvm_handle_ptrauth(struct kvm_vcpu *vcpu, struct kvm_run *run) { - kvm_arm_vcpu_ptrauth_trap(vcpu); + kvm_inject_undefined(vcpu); return 1; } diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index c07a45643cd4..d60c2ef0fe8c 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -490,6 +490,64 @@ static bool __hyp_text handle_tx2_tvm(struct kvm_vcpu *vcpu) return true; } +static bool __hyp_text esr_is_ptrauth_trap(u32 esr) +{ + u32 ec = ESR_ELx_EC(esr); + + if (ec == ESR_ELx_EC_PAC) + return true; + + if (ec != ESR_ELx_EC_SYS64) + return false; + + switch (esr_sys64_to_sysreg(esr)) { + case SYS_APIAKEYLO_EL1: + case SYS_APIAKEYHI_EL1: + case SYS_APIBKEYLO_EL1: + case SYS_APIBKEYHI_EL1: + case SYS_APDAKEYLO_EL1: + case SYS_APDAKEYHI_EL1: + case SYS_APDBKEYLO_EL1: + case SYS_APDBKEYHI_EL1: + case SYS_APGAKEYLO_EL1: + case SYS_APGAKEYHI_EL1: + return true; + } + + return false; +} + +#define __ptrauth_save_key(regs, key) \ +({ \ + regs[key ## KEYLO_EL1] = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \ + regs[key ## KEYHI_EL1] = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \ +}) + +static bool __hyp_text __hyp_handle_ptrauth(struct kvm_vcpu *vcpu) +{ + struct kvm_cpu_context *ctxt; + u64 val; + + if (!vcpu_has_ptrauth(vcpu) || + !esr_is_ptrauth_trap(kvm_vcpu_get_hsr(vcpu))) + return false; + + ctxt = kern_hyp_va(vcpu->arch.host_cpu_context); + __ptrauth_save_key(ctxt->sys_regs, APIA); + __ptrauth_save_key(ctxt->sys_regs, APIB); + __ptrauth_save_key(ctxt->sys_regs, APDA); + __ptrauth_save_key(ctxt->sys_regs, APDB); + __ptrauth_save_key(ctxt->sys_regs, APGA); + + vcpu_ptrauth_enable(vcpu); + + val = read_sysreg(hcr_el2); + val |= (HCR_API | HCR_APK); + write_sysreg(val, hcr_el2); + + return true; +} + /* * Return true when we were able to fixup the guest exit and should return to * the guest, false when we should restore the host state and return to the @@ -524,6 +582,9 @@ static bool __hyp_text fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code) if (__hyp_handle_fpsimd(vcpu)) return true; + if (__hyp_handle_ptrauth(vcpu)) + return true; + if (!__populate_fault_info(vcpu)) return true; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index ad1d57501d6d..564995084cf8 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1034,16 +1034,13 @@ static bool trap_ptrauth(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *rd) { - kvm_arm_vcpu_ptrauth_trap(vcpu); - /* - * Return false for both cases as we never skip the trapped - * instruction: - * - * - Either we re-execute the same key register access instruction - * after enabling ptrauth. - * - Or an UNDEF is injected as ptrauth is not supported/enabled. + * If we land here, that is because we didn't fixup the access on exit + * by allowing the PtrAuth sysregs. The only way this happens is when + * the guest does not have PtrAuth support enabled. */ + kvm_inject_undefined(vcpu); + return false; }