diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/hyp-entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S new file mode 100644 index 000000000000..93e8d983c0bd --- /dev/null +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -0,0 +1,212 @@ +/* + * Copyright (C) 2015 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@arm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/linkage.h> + +#include <asm/alternative.h> +#include <asm/assembler.h> +#include <asm/asm-offsets.h> +#include <asm/cpufeature.h> +#include <asm/kvm_arm.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_mmu.h> + + .text + .pushsection .hyp.text, "ax" + +.macro save_x0_to_x3 + stp x0, x1, [sp, #-16]! + stp x2, x3, [sp, #-16]! +.endm + +.macro restore_x0_to_x3 + ldp x2, x3, [sp], #16 + ldp x0, x1, [sp], #16 +.endm + +el1_sync: // Guest trapped into EL2 + save_x0_to_x3 + + mrs x1, esr_el2 + lsr x2, x1, #ESR_ELx_EC_SHIFT + + cmp x2, #ESR_ELx_EC_HVC64 + b.ne el1_trap + + mrs x3, vttbr_el2 // If vttbr is valid, the 64bit guest + cbnz x3, el1_trap // called HVC + + /* Here, we're pretty sure the host called HVC. */ + restore_x0_to_x3 + + /* Check for __hyp_get_vectors */ + cbnz x0, 1f + mrs x0, vbar_el2 + b 2f + +1: stp lr, xzr, [sp, #-16]! + + /* + * Compute the function address in EL2, and shuffle the parameters. + */ + kern_hyp_va x0 + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + + ldp lr, xzr, [sp], #16 +2: eret + +el1_trap: + /* + * x1: ESR + * x2: ESR_EC + */ + + /* Guest accessed VFP/SIMD registers, save host, restore Guest */ + cmp x2, #ESR_ELx_EC_FP_ASIMD + b.eq __fpsimd_guest_restore + + cmp x2, #ESR_ELx_EC_DABT_LOW + mov x0, #ESR_ELx_EC_IABT_LOW + ccmp x2, x0, #4, ne + b.ne 1f // Not an abort we care about + + /* This is an abort. Check for permission fault */ +alternative_if_not ARM64_WORKAROUND_834220 + and x2, x1, #ESR_ELx_FSC_TYPE + cmp x2, #FSC_PERM + b.ne 1f // Not a permission fault +alternative_else + nop // Use the permission fault path to + nop // check for a valid S1 translation, + nop // regardless of the ESR value. +alternative_endif + + /* + * Check for Stage-1 page table walk, which is guaranteed + * to give a valid HPFAR_EL2. + */ + tbnz x1, #7, 1f // S1PTW is set + + /* Preserve PAR_EL1 */ + mrs x3, par_el1 + stp x3, xzr, [sp, #-16]! + + /* + * Permission fault, HPFAR_EL2 is invalid. + * Resolve the IPA the hard way using the guest VA. + * Stage-1 translation already validated the memory access rights. + * As such, we can use the EL1 translation regime, and don't have + * to distinguish between EL0 and EL1 access. + */ + mrs x2, far_el2 + at s1e1r, x2 + isb + + /* Read result */ + mrs x3, par_el1 + ldp x0, xzr, [sp], #16 // Restore PAR_EL1 from the stack + msr par_el1, x0 + tbnz x3, #0, 3f // Bail out if we failed the translation + ubfx x3, x3, #12, #36 // Extract IPA + lsl x3, x3, #4 // and present it like HPFAR + b 2f + +1: mrs x3, hpfar_el2 + mrs x2, far_el2 + +2: mrs x0, tpidr_el2 + str w1, [x0, #VCPU_ESR_EL2] + str x2, [x0, #VCPU_FAR_EL2] + str x3, [x0, #VCPU_HPFAR_EL2] + + mov x1, #ARM_EXCEPTION_TRAP + b __guest_exit + + /* + * Translation failed. Just return to the guest and + * let it fault again. Another CPU is probably playing + * behind our back. + */ +3: restore_x0_to_x3 + + eret + +el1_irq: + save_x0_to_x3 + mrs x0, tpidr_el2 + mov x1, #ARM_EXCEPTION_IRQ + b __guest_exit + +ENTRY(__hyp_do_panic) + mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\ + PSR_MODE_EL1h) + msr spsr_el2, lr + ldr lr, =panic + msr elr_el2, lr + eret +ENDPROC(__hyp_do_panic) + +.macro invalid_vector label, target = __hyp_panic + .align 2 +\label: + b \target +ENDPROC(\label) +.endm + + /* None of these should ever happen */ + invalid_vector el2t_sync_invalid + invalid_vector el2t_irq_invalid + invalid_vector el2t_fiq_invalid + invalid_vector el2t_error_invalid + invalid_vector el2h_sync_invalid + invalid_vector el2h_irq_invalid + invalid_vector el2h_fiq_invalid + invalid_vector el2h_error_invalid + invalid_vector el1_sync_invalid + invalid_vector el1_irq_invalid + invalid_vector el1_fiq_invalid + invalid_vector el1_error_invalid + + .ltorg + + .align 11 + +ENTRY(__kvm_hyp_vector) + ventry el2t_sync_invalid // Synchronous EL2t + ventry el2t_irq_invalid // IRQ EL2t + ventry el2t_fiq_invalid // FIQ EL2t + ventry el2t_error_invalid // Error EL2t + + ventry el2h_sync_invalid // Synchronous EL2h + ventry el2h_irq_invalid // IRQ EL2h + ventry el2h_fiq_invalid // FIQ EL2h + ventry el2h_error_invalid // Error EL2h + + ventry el1_sync // Synchronous 64-bit EL1 + ventry el1_irq // IRQ 64-bit EL1 + ventry el1_fiq_invalid // FIQ 64-bit EL1 + ventry el1_error_invalid // Error 64-bit EL1 + + ventry el1_sync // Synchronous 32-bit EL1 + ventry el1_irq // IRQ 32-bit EL1 + ventry el1_fiq_invalid // FIQ 32-bit EL1 + ventry el1_error_invalid // Error 32-bit EL1 +ENDPROC(__kvm_hyp_vector) |