diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/exception.c')
| -rw-r--r-- | arch/arm64/kvm/hyp/exception.c | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c index 6533a9270850..94d6d823424d 100644 --- a/arch/arm64/kvm/hyp/exception.c +++ b/arch/arm64/kvm/hyp/exception.c @@ -11,7 +11,143 @@ */ #include <hyp/adjust_pc.h> +#include <linux/kvm_host.h> +#include <asm/kvm_emulate.h> + +#if !defined (__KVM_NVHE_HYPERVISOR__) && !defined (__KVM_VHE_HYPERVISOR__) +#error Hypervisor code only! +#endif + +static inline u64 __vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) +{ + u64 val; + + if (__vcpu_read_sys_reg_from_cpu(reg, &val)) + return val; + + return __vcpu_sys_reg(vcpu, reg); +} + +static inline void __vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) +{ + if (__vcpu_write_sys_reg_to_cpu(val, reg)) + return; + + __vcpu_sys_reg(vcpu, reg) = val; +} + +static void __vcpu_write_spsr(struct kvm_vcpu *vcpu, u64 val) +{ + write_sysreg_el1(val, SYS_SPSR); +} + +/* + * This performs the exception entry at a given EL (@target_mode), stashing PC + * and PSTATE into ELR and SPSR respectively, and compute the new PC/PSTATE. + * The EL passed to this function *must* be a non-secure, privileged mode with + * bit 0 being set (PSTATE.SP == 1). + * + * When an exception is taken, most PSTATE fields are left unchanged in the + * handler. However, some are explicitly overridden (e.g. M[4:0]). Luckily all + * of the inherited bits have the same position in the AArch64/AArch32 SPSR_ELx + * layouts, so we don't need to shuffle these for exceptions from AArch32 EL0. + * + * For the SPSR_ELx layout for AArch64, see ARM DDI 0487E.a page C5-429. + * For the SPSR_ELx layout for AArch32, see ARM DDI 0487E.a page C5-426. + * + * Here we manipulate the fields in order of the AArch64 SPSR_ELx layout, from + * MSB to LSB. + */ +static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, + enum exception_type type) +{ + unsigned long sctlr, vbar, old, new, mode; + u64 exc_offset; + + mode = *vcpu_cpsr(vcpu) & (PSR_MODE_MASK | PSR_MODE32_BIT); + + if (mode == target_mode) + exc_offset = CURRENT_EL_SP_ELx_VECTOR; + else if ((mode | PSR_MODE_THREAD_BIT) == target_mode) + exc_offset = CURRENT_EL_SP_EL0_VECTOR; + else if (!(mode & PSR_MODE32_BIT)) + exc_offset = LOWER_EL_AArch64_VECTOR; + else + exc_offset = LOWER_EL_AArch32_VECTOR; + + switch (target_mode) { + case PSR_MODE_EL1h: + vbar = __vcpu_read_sys_reg(vcpu, VBAR_EL1); + sctlr = __vcpu_read_sys_reg(vcpu, SCTLR_EL1); + __vcpu_write_sys_reg(vcpu, *vcpu_pc(vcpu), ELR_EL1); + break; + default: + /* Don't do that */ + BUG(); + } + + *vcpu_pc(vcpu) = vbar + exc_offset + type; + + old = *vcpu_cpsr(vcpu); + new = 0; + + new |= (old & PSR_N_BIT); + new |= (old & PSR_Z_BIT); + new |= (old & PSR_C_BIT); + new |= (old & PSR_V_BIT); + + // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests) + + new |= (old & PSR_DIT_BIT); + + // PSTATE.UAO is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D5-2579. + + // PSTATE.PAN is unchanged unless SCTLR_ELx.SPAN == 0b0 + // SCTLR_ELx.SPAN is RES1 when ARMv8.1-PAN is not implemented + // See ARM DDI 0487E.a, page D5-2578. + new |= (old & PSR_PAN_BIT); + if (!(sctlr & SCTLR_EL1_SPAN)) + new |= PSR_PAN_BIT; + + // PSTATE.SS is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D2-2452. + + // PSTATE.IL is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, page D1-2306. + + // PSTATE.SSBS is set to SCTLR_ELx.DSSBS upon any exception to AArch64 + // See ARM DDI 0487E.a, page D13-3258 + if (sctlr & SCTLR_ELx_DSSBS) + new |= PSR_SSBS_BIT; + + // PSTATE.BTYPE is set to zero upon any exception to AArch64 + // See ARM DDI 0487E.a, pages D1-2293 to D1-2294. + + new |= PSR_D_BIT; + new |= PSR_A_BIT; + new |= PSR_I_BIT; + new |= PSR_F_BIT; + + new |= target_mode; + + *vcpu_cpsr(vcpu) = new; + __vcpu_write_spsr(vcpu, old); +} void kvm_inject_exception(struct kvm_vcpu *vcpu) { + switch (vcpu->arch.flags & KVM_ARM64_EXCEPT_MASK) { + case (KVM_ARM64_EXCEPT_AA64_ELx_SYNC | + KVM_ARM64_EXCEPT_AA64_EL1): + enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync); + break; + default: + /* + * Only EL1_SYNC makes sense so far, EL2_{SYNC,IRQ} + * will be implemented at some point. Everything + * else gets silently ignored. + */ + break; + } } |