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Diffstat (limited to 'arch/arm64/kvm/inject_fault.c')
| -rw-r--r-- | arch/arm64/kvm/inject_fault.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c new file mode 100644 index 000000000..34a96ab24 --- /dev/null +++ b/arch/arm64/kvm/inject_fault.c @@ -0,0 +1,239 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Fault injection for both 32 and 64bit guests. + * + * Copyright (C) 2012,2013 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@arm.com> + * + * Based on arch/arm/kvm/emulate.c + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall <c.dall@virtualopensystems.com> + */ + +#include <linux/kvm_host.h> +#include <asm/kvm_emulate.h> +#include <asm/esr.h> + +#define CURRENT_EL_SP_EL0_VECTOR 0x0 +#define CURRENT_EL_SP_ELx_VECTOR 0x200 +#define LOWER_EL_AArch64_VECTOR 0x400 +#define LOWER_EL_AArch32_VECTOR 0x600 + +enum exception_type { + except_type_sync = 0, + except_type_irq = 0x80, + except_type_fiq = 0x100, + except_type_serror = 0x180, +}; + +/* + * 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); +} + +static void inject_abt64(struct kvm_vcpu *vcpu, bool is_iabt, unsigned long addr) +{ + unsigned long cpsr = *vcpu_cpsr(vcpu); + bool is_aarch32 = vcpu_mode_is_32bit(vcpu); + u32 esr = 0; + + enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync); + + vcpu_write_sys_reg(vcpu, addr, FAR_EL1); + + /* + * Build an {i,d}abort, depending on the level and the + * instruction set. Report an external synchronous abort. + */ + if (kvm_vcpu_trap_il_is32bit(vcpu)) + esr |= ESR_ELx_IL; + + /* + * Here, the guest runs in AArch64 mode when in EL1. If we get + * an AArch32 fault, it means we managed to trap an EL0 fault. + */ + if (is_aarch32 || (cpsr & PSR_MODE_MASK) == PSR_MODE_EL0t) + esr |= (ESR_ELx_EC_IABT_LOW << ESR_ELx_EC_SHIFT); + else + esr |= (ESR_ELx_EC_IABT_CUR << ESR_ELx_EC_SHIFT); + + if (!is_iabt) + esr |= ESR_ELx_EC_DABT_LOW << ESR_ELx_EC_SHIFT; + + vcpu_write_sys_reg(vcpu, esr | ESR_ELx_FSC_EXTABT, ESR_EL1); +} + +static void inject_undef64(struct kvm_vcpu *vcpu) +{ + u32 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT); + + enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync); + + /* + * Build an unknown exception, depending on the instruction + * set. + */ + if (kvm_vcpu_trap_il_is32bit(vcpu)) + esr |= ESR_ELx_IL; + + vcpu_write_sys_reg(vcpu, esr, ESR_EL1); +} + +/** + * kvm_inject_dabt - inject a data abort into the guest + * @vcpu: The VCPU to receive the data abort + * @addr: The address to report in the DFAR + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + */ +void kvm_inject_dabt(struct kvm_vcpu *vcpu, unsigned long addr) +{ + if (vcpu_el1_is_32bit(vcpu)) + kvm_inject_dabt32(vcpu, addr); + else + inject_abt64(vcpu, false, addr); +} + +/** + * kvm_inject_pabt - inject a prefetch abort into the guest + * @vcpu: The VCPU to receive the prefetch abort + * @addr: The address to report in the DFAR + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + */ +void kvm_inject_pabt(struct kvm_vcpu *vcpu, unsigned long addr) +{ + if (vcpu_el1_is_32bit(vcpu)) + kvm_inject_pabt32(vcpu, addr); + else + inject_abt64(vcpu, true, addr); +} + +/** + * kvm_inject_undefined - inject an undefined instruction into the guest + * @vcpu: The vCPU in which to inject the exception + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + */ +void kvm_inject_undefined(struct kvm_vcpu *vcpu) +{ + if (vcpu_el1_is_32bit(vcpu)) + kvm_inject_undef32(vcpu); + else + inject_undef64(vcpu); +} + +void kvm_set_sei_esr(struct kvm_vcpu *vcpu, u64 esr) +{ + vcpu_set_vsesr(vcpu, esr & ESR_ELx_ISS_MASK); + *vcpu_hcr(vcpu) |= HCR_VSE; +} + +/** + * kvm_inject_vabt - inject an async abort / SError into the guest + * @vcpu: The VCPU to receive the exception + * + * It is assumed that this code is called from the VCPU thread and that the + * VCPU therefore is not currently executing guest code. + * + * Systems with the RAS Extensions specify an imp-def ESR (ISV/IDS = 1) with + * the remaining ISS all-zeros so that this error is not interpreted as an + * uncategorized RAS error. Without the RAS Extensions we can't specify an ESR + * value, so the CPU generates an imp-def value. + */ +void kvm_inject_vabt(struct kvm_vcpu *vcpu) +{ + kvm_set_sei_esr(vcpu, ESR_ELx_ISV); +} |