Add exception injection support for s390 KVM arm64 architecture. This implements the core exception entry mechanism and fault injection functions needed for proper guest exception handling. Co-developed-by: Andreas Grapentin Signed-off-by: Andreas Grapentin Signed-off-by: Steffen Eiden --- arch/s390/include/asm/kvm_host_arm64.h | 2 + arch/s390/kvm/arm64/Makefile | 1 + arch/s390/kvm/arm64/arm.c | 15 +--- arch/s390/kvm/arm64/exception.c | 105 +++++++++++++++++++++++++ arch/s390/kvm/arm64/inject_fault.c | 72 ++++++++++++++++- 5 files changed, 182 insertions(+), 13 deletions(-) create mode 100644 arch/s390/kvm/arm64/exception.c diff --git a/arch/s390/include/asm/kvm_host_arm64.h b/arch/s390/include/asm/kvm_host_arm64.h index cc457d69621c..34d131b36e70 100644 --- a/arch/s390/include/asm/kvm_host_arm64.h +++ b/arch/s390/include/asm/kvm_host_arm64.h @@ -373,4 +373,6 @@ static inline u64 kvm_sanitised_host_ftr_reg(u32 id) return kvm_arm_host_sys_reg_by_id(id); } +void kvm_adjust_pc(struct kvm_vcpu *vcpu); + #endif /* ASM_KVM_HOST_ARM64_H */ diff --git a/arch/s390/kvm/arm64/Makefile b/arch/s390/kvm/arm64/Makefile index bec24b60a071..9d6b7d5bf588 100644 --- a/arch/s390/kvm/arm64/Makefile +++ b/arch/s390/kvm/arm64/Makefile @@ -9,6 +9,7 @@ ccflags-y += -I $(src) -I$(srctree)/arch/s390/kvm/gmap -DKVM_S390_ARM64 kvm-arm64-obj := \ arm.o \ + exception.o \ feature.o \ guest.o \ handle_exit.o \ diff --git a/arch/s390/kvm/arm64/arm.c b/arch/s390/kvm/arm64/arm.c index 88b66552cff0..c62e50002628 100644 --- a/arch/s390/kvm/arm64/arm.c +++ b/arch/s390/kvm/arm64/arm.c @@ -350,19 +350,11 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level, return 0; } -static void adjust_pc(struct kvm_vcpu *vcpu) -{ - if (vcpu_get_flag(vcpu, INCREMENT_PC)) { - kvm_skip_instr(vcpu); - vcpu_clear_flag(vcpu, INCREMENT_PC); - } -} - static void arm_vcpu_run(struct kvm_vcpu *vcpu) { struct kvm_sae_block *sae_block = &vcpu->arch.sae_block; - adjust_pc(vcpu); + kvm_adjust_pc(vcpu); local_irq_disable(); guest_enter_irqoff(); @@ -457,8 +449,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu) kvm_sigset_deactivate(vcpu); out: - if (unlikely(vcpu_get_flag(vcpu, INCREMENT_PC))) - adjust_pc(vcpu); + if (unlikely(vcpu_get_flag(vcpu, PENDING_EXCEPTION) || + vcpu_get_flag(vcpu, INCREMENT_PC))) + kvm_adjust_pc(vcpu); save_vx_regs(vcpu->arch.ctxt.vregs); kernel_fpu_end(&fpu_save, KERNEL_FPC | KERNEL_VXR); diff --git a/arch/s390/kvm/arm64/exception.c b/arch/s390/kvm/arm64/exception.c new file mode 100644 index 000000000000..871e4e2c710a --- /dev/null +++ b/arch/s390/kvm/arm64/exception.c @@ -0,0 +1,105 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include +#include + +#include + +/* + * 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_pstate, new, mode; + u64 exc_offset; + + old_pstate = *vcpu_cpsr(vcpu); + mode = old_pstate & (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); + vcpu_write_sys_reg(vcpu, old_pstate, SPSR_EL1); + break; + default: + panic("Unknown PSR Mode: 0x%lx.", target_mode); + } + + *vcpu_pc(vcpu) = vbar + exc_offset + type; + + new = 0; + + new |= (old_pstate & PSR_N_BIT); + new |= (old_pstate & PSR_Z_BIT); + new |= (old_pstate & PSR_C_BIT); + new |= (old_pstate & PSR_V_BIT); + new |= (old_pstate & PSR_DIT_BIT); + new |= (old_pstate & PSR_PAN_BIT); + + if (!(sctlr & SCTLR_EL1_SPAN)) + new |= PSR_PAN_BIT; + + if (sctlr & SCTLR_ELx_DSSBS) + new |= PSR_SSBS_BIT; + + new |= PSR_D_BIT; + new |= PSR_A_BIT; + new |= PSR_I_BIT; + new |= PSR_F_BIT; + + new |= target_mode; + + *vcpu_cpsr(vcpu) = new; +} + +static void kvm_inject_exception(struct kvm_vcpu *vcpu) +{ + switch (vcpu_get_flag(vcpu, EXCEPT_MASK)) { + case unpack_vcpu_flag(EXCEPT_AA64_EL1_SYNC): + enter_exception64(vcpu, PSR_MODE_EL1h, except_type_sync); + break; + } +} + +/* + * Adjust the guest PC (and potentially exception state) depending on + * flags provided by the emulation code. + */ +void kvm_adjust_pc(struct kvm_vcpu *vcpu) +{ + if (vcpu_get_flag(vcpu, PENDING_EXCEPTION)) { + kvm_inject_exception(vcpu); + vcpu_clear_flag(vcpu, PENDING_EXCEPTION); + vcpu_clear_flag(vcpu, EXCEPT_MASK); + } else if (vcpu_get_flag(vcpu, INCREMENT_PC)) { + kvm_skip_instr(vcpu); + vcpu_clear_flag(vcpu, INCREMENT_PC); + } +} diff --git a/arch/s390/kvm/arm64/inject_fault.c b/arch/s390/kvm/arm64/inject_fault.c index 650c041efde2..0216ffbd62ab 100644 --- a/arch/s390/kvm/arm64/inject_fault.c +++ b/arch/s390/kvm/arm64/inject_fault.c @@ -2,6 +2,42 @@ #include +#define exception_esr_elx(__vcpu) ESR_EL1 +#define exception_far_elx(__vcpu) FAR_EL1 + +static void pend_sync_exception(struct kvm_vcpu *vcpu) +{ + kvm_pend_exception(vcpu, EXCEPT_AA64_EL1_SYNC); +} + +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); + u64 esr = 0; + + if (kvm_vcpu_abt_iss1tw(vcpu)) + esr |= ESR_ELx_FSC_SEA_TTW(kvm_vcpu_abt_gltl(vcpu)); + else + esr |= ESR_ELx_FSC_EXTABT; + + pend_sync_exception(vcpu); + + if (kvm_vcpu_trap_il_is32bit(vcpu)) + esr |= ESR_ELx_IL; + + 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, addr, ESR_EL1); + vcpu_write_sys_reg(vcpu, esr, FAR_EL1); +} + /** * kvm_inject_undefined - inject an undefined instruction into the guest * @vcpu: The vCPU in which to inject the exception @@ -11,11 +47,43 @@ */ void kvm_inject_undefined(struct kvm_vcpu *vcpu) { - /* Stub until s390 supports arm64 sysregs TODO sysregs*/ + u64 esr = (ESR_ELx_EC_UNKNOWN << ESR_ELx_EC_SHIFT); + + pend_sync_exception(vcpu); + + /* + * 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, exception_esr_elx(vcpu)); +} + +static void __kvm_inject_sea(struct kvm_vcpu *vcpu, bool iabt, u64 addr) +{ + inject_abt64(vcpu, iabt, addr); } int kvm_inject_sea(struct kvm_vcpu *vcpu, bool iabt, u64 addr) { - /* Stub until s390 supports arm64 sysregs TODO sysregs*/ + lockdep_assert_held(&vcpu->mutex); + + __kvm_inject_sea(vcpu, iabt, addr); return 1; } + +void kvm_inject_size_fault(struct kvm_vcpu *vcpu) +{ + unsigned long addr, esr; + + addr = kvm_vcpu_get_fault_ipa(vcpu); + addr |= FAR_TO_FIPA_OFFSET(kvm_vcpu_get_hfar(vcpu)); + + __kvm_inject_sea(vcpu, kvm_vcpu_trap_is_iabt(vcpu), addr); + + esr = vcpu_read_sys_reg(vcpu, exception_esr_elx(vcpu)); + esr &= ~GENMASK_ULL(5, 0); + vcpu_write_sys_reg(vcpu, esr, exception_esr_elx(vcpu)); +} -- 2.53.0