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Diffstat (limited to 'arch/arm64/kvm/hyp/entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S new file mode 100644 index 000000000000..ac65c52d6275 --- /dev/null +++ b/arch/arm64/kvm/hyp/entry.S @@ -0,0 +1,180 @@ +/* + * 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/asm-offsets.h> +#include <asm/assembler.h> +#include <asm/fpsimdmacros.h> +#include <asm/kvm.h> +#include <asm/kvm_arm.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_mmu.h> + +#define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) +#define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) +#define CPU_SYSREG_OFFSET(x) (CPU_SYSREGS + 8*x) + + .text + .pushsection .hyp.text, "ax" + +.macro save_callee_saved_regs ctxt + stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] + stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] + stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] + stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] + stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] + stp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] +.endm + +.macro restore_callee_saved_regs ctxt + ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] + ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] + ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] + ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] + ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] + ldp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] +.endm + +/* + * u64 __guest_enter(struct kvm_vcpu *vcpu, + * struct kvm_cpu_context *host_ctxt); + */ +ENTRY(__guest_enter) + // x0: vcpu + // x1: host/guest context + // x2-x18: clobbered by macros + + // Store the host regs + save_callee_saved_regs x1 + + // Preserve vcpu & host_ctxt for use at exit time + stp x0, x1, [sp, #-16]! + + add x1, x0, #VCPU_CONTEXT + + // Prepare x0-x1 for later restore by pushing them onto the stack + ldp x2, x3, [x1, #CPU_XREG_OFFSET(0)] + stp x2, x3, [sp, #-16]! + + // x2-x18 + ldp x2, x3, [x1, #CPU_XREG_OFFSET(2)] + ldp x4, x5, [x1, #CPU_XREG_OFFSET(4)] + ldp x6, x7, [x1, #CPU_XREG_OFFSET(6)] + ldp x8, x9, [x1, #CPU_XREG_OFFSET(8)] + ldp x10, x11, [x1, #CPU_XREG_OFFSET(10)] + ldp x12, x13, [x1, #CPU_XREG_OFFSET(12)] + ldp x14, x15, [x1, #CPU_XREG_OFFSET(14)] + ldp x16, x17, [x1, #CPU_XREG_OFFSET(16)] + ldr x18, [x1, #CPU_XREG_OFFSET(18)] + + // x19-x29, lr + restore_callee_saved_regs x1 + + // Last bits of the 64bit state + ldp x0, x1, [sp], #16 + + // Do not touch any register after this! + eret +ENDPROC(__guest_enter) + +ENTRY(__guest_exit) + // x0: vcpu + // x1: return code + // x2-x3: free + // x4-x29,lr: vcpu regs + // vcpu x0-x3 on the stack + + add x2, x0, #VCPU_CONTEXT + + stp x4, x5, [x2, #CPU_XREG_OFFSET(4)] + stp x6, x7, [x2, #CPU_XREG_OFFSET(6)] + stp x8, x9, [x2, #CPU_XREG_OFFSET(8)] + stp x10, x11, [x2, #CPU_XREG_OFFSET(10)] + stp x12, x13, [x2, #CPU_XREG_OFFSET(12)] + stp x14, x15, [x2, #CPU_XREG_OFFSET(14)] + stp x16, x17, [x2, #CPU_XREG_OFFSET(16)] + str x18, [x2, #CPU_XREG_OFFSET(18)] + + ldp x6, x7, [sp], #16 // x2, x3 + ldp x4, x5, [sp], #16 // x0, x1 + + stp x4, x5, [x2, #CPU_XREG_OFFSET(0)] + stp x6, x7, [x2, #CPU_XREG_OFFSET(2)] + + save_callee_saved_regs x2 + + // Restore vcpu & host_ctxt from the stack + // (preserving return code in x1) + ldp x0, x2, [sp], #16 + // Now restore the host regs + restore_callee_saved_regs x2 + + mov x0, x1 + ret +ENDPROC(__guest_exit) + +ENTRY(__fpsimd_guest_restore) + stp x4, lr, [sp, #-16]! + + mrs x2, cptr_el2 + bic x2, x2, #CPTR_EL2_TFP + msr cptr_el2, x2 + isb + + mrs x3, tpidr_el2 + + ldr x0, [x3, #VCPU_HOST_CONTEXT] + kern_hyp_va x0 + add x0, x0, #CPU_GP_REG_OFFSET(CPU_FP_REGS) + bl __fpsimd_save_state + + add x2, x3, #VCPU_CONTEXT + add x0, x2, #CPU_GP_REG_OFFSET(CPU_FP_REGS) + bl __fpsimd_restore_state + + // Skip restoring fpexc32 for AArch64 guests + mrs x1, hcr_el2 + tbnz x1, #HCR_RW_SHIFT, 1f + ldr x4, [x2, #CPU_SYSREG_OFFSET(FPEXC32_EL2)] + msr fpexc32_el2, x4 +1: + ldp x4, lr, [sp], #16 + ldp x2, x3, [sp], #16 + ldp x0, x1, [sp], #16 + + eret +ENDPROC(__fpsimd_guest_restore) + +/* + * When using the extended idmap, we don't have a trampoline page we can use + * while we switch pages tables during __kvm_hyp_reset. Accessing the idmap + * directly would be ideal, but if we're using the extended idmap then the + * idmap is located above HYP_PAGE_OFFSET, and the address will be masked by + * kvm_call_hyp using kern_hyp_va. + * + * x0: HYP boot pgd + * x1: HYP phys_idmap_start + */ +ENTRY(__extended_idmap_trampoline) + mov x4, x1 + adr_l x3, __kvm_hyp_reset + + /* insert __kvm_hyp_reset()s offset into phys_idmap_start */ + bfi x4, x3, #0, #PAGE_SHIFT + br x4 +ENDPROC(__extended_idmap_trampoline) |