diff options
Diffstat (limited to 'arch/arm64/kvm/hyp/entry.S')
| -rw-r--r-- | arch/arm64/kvm/hyp/entry.S | 217 |
1 files changed, 138 insertions, 79 deletions
diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 675fdc186e3b..9f4e8d68ab50 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -1,92 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * 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/alternative.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) +#include <asm/kvm_mte.h> +#include <asm/kvm_ptrauth.h> .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); + * u64 __guest_enter(struct kvm_vcpu *vcpu); */ -ENTRY(__guest_enter) +SYM_FUNC_START(__guest_enter) // x0: vcpu - // x1: host context - // x2-x17: clobbered by macros - // x18: guest context + // x1-x17: clobbered by macros + // x29: guest context + + adr_this_cpu x1, kvm_hyp_ctxt, x2 - // Store the host regs + // Store the hyp regs save_callee_saved_regs x1 - add x18, x0, #VCPU_CONTEXT + // Save hyp's sp_el0 + save_sp_el0 x1, x2 + + // Now the hyp state is stored if we have a pending RAS SError it must + // affect the host or hyp. If any asynchronous exception is pending we + // defer the guest entry. The DSB isn't necessary before v8.2 as any + // SError would be fatal. +alternative_if ARM64_HAS_RAS_EXTN + dsb nshst + isb +alternative_else_nop_endif + mrs x1, isr_el1 + cbz x1, 1f + + // Ensure that __guest_enter() always provides a context + // synchronization event so that callers don't need ISBs for anything + // that would usually be synchonized by the ERET. + isb + mov x0, #ARM_EXCEPTION_IRQ + ret + +1: + set_loaded_vcpu x0, x1, x2 + + add x29, x0, #VCPU_CONTEXT + + // mte_switch_to_guest(g_ctxt, h_ctxt, tmp1) + mte_switch_to_guest x29, x1, x2 + + // Macro ptrauth_switch_to_guest format: + // ptrauth_switch_to_guest(guest cxt, tmp1, tmp2, tmp3) + // The below macro to restore guest keys is not implemented in C code + // as it may cause Pointer Authentication key signing mismatch errors + // when this feature is enabled for kernel code. + ptrauth_switch_to_guest x29, x0, x1, x2 + + // Restore the guest's sp_el0 + restore_sp_el0 x29, x0 // Restore guest regs x0-x17 - ldp x0, x1, [x18, #CPU_XREG_OFFSET(0)] - ldp x2, x3, [x18, #CPU_XREG_OFFSET(2)] - ldp x4, x5, [x18, #CPU_XREG_OFFSET(4)] - ldp x6, x7, [x18, #CPU_XREG_OFFSET(6)] - ldp x8, x9, [x18, #CPU_XREG_OFFSET(8)] - ldp x10, x11, [x18, #CPU_XREG_OFFSET(10)] - ldp x12, x13, [x18, #CPU_XREG_OFFSET(12)] - ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)] - ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)] - - // Restore guest regs x19-x29, lr - restore_callee_saved_regs x18 - - // Restore guest reg x18 - ldr x18, [x18, #CPU_XREG_OFFSET(18)] + ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)] + ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)] + ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)] + ldp x6, x7, [x29, #CPU_XREG_OFFSET(6)] + ldp x8, x9, [x29, #CPU_XREG_OFFSET(8)] + ldp x10, x11, [x29, #CPU_XREG_OFFSET(10)] + ldp x12, x13, [x29, #CPU_XREG_OFFSET(12)] + ldp x14, x15, [x29, #CPU_XREG_OFFSET(14)] + ldp x16, x17, [x29, #CPU_XREG_OFFSET(16)] + + // Restore guest regs x18-x29, lr + restore_callee_saved_regs x29 // Do not touch any register after this! eret sb -ENDPROC(__guest_enter) -ENTRY(__guest_exit) +SYM_INNER_LABEL(__guest_exit_restore_elr_and_panic, SYM_L_GLOBAL) + // x2-x29,lr: vcpu regs + // vcpu x0-x1 on the stack + + adr_this_cpu x0, kvm_hyp_ctxt, x1 + ldr x0, [x0, #CPU_ELR_EL2] + msr elr_el2, x0 + +SYM_INNER_LABEL(__guest_exit_panic, SYM_L_GLOBAL) + // x2-x29,lr: vcpu regs + // vcpu x0-x1 on the stack + + // If the hyp context is loaded, go straight to hyp_panic + get_loaded_vcpu x0, x1 + cbnz x0, 1f + b hyp_panic + +1: + // The hyp context is saved so make sure it is restored to allow + // hyp_panic to run at hyp and, subsequently, panic to run in the host. + // This makes use of __guest_exit to avoid duplication but sets the + // return address to tail call into hyp_panic. As a side effect, the + // current state is saved to the guest context but it will only be + // accurate if the guest had been completely restored. + adr_this_cpu x0, kvm_hyp_ctxt, x1 + adr_l x1, hyp_panic + str x1, [x0, #CPU_XREG_OFFSET(30)] + + get_vcpu_ptr x1, x0 + +SYM_INNER_LABEL(__guest_exit, SYM_L_GLOBAL) // x0: return code // x1: vcpu // x2-x29,lr: vcpu regs @@ -102,7 +134,7 @@ ENTRY(__guest_exit) // Retrieve the guest regs x0-x1 from the stack ldp x2, x3, [sp], #16 // x0, x1 - // Store the guest regs x0-x1 and x4-x18 + // Store the guest regs x0-x1 and x4-x17 stp x2, x3, [x1, #CPU_XREG_OFFSET(0)] stp x4, x5, [x1, #CPU_XREG_OFFSET(4)] stp x6, x7, [x1, #CPU_XREG_OFFSET(6)] @@ -111,20 +143,37 @@ ENTRY(__guest_exit) stp x12, x13, [x1, #CPU_XREG_OFFSET(12)] stp x14, x15, [x1, #CPU_XREG_OFFSET(14)] stp x16, x17, [x1, #CPU_XREG_OFFSET(16)] - str x18, [x1, #CPU_XREG_OFFSET(18)] - // Store the guest regs x19-x29, lr + // Store the guest regs x18-x29, lr save_callee_saved_regs x1 - get_host_ctxt x2, x3 + // Store the guest's sp_el0 + save_sp_el0 x1, x2 + + adr_this_cpu x2, kvm_hyp_ctxt, x3 - // Now restore the host regs + // Macro ptrauth_switch_to_hyp format: + // ptrauth_switch_to_hyp(guest cxt, host cxt, tmp1, tmp2, tmp3) + // The below macro to save/restore keys is not implemented in C code + // as it may cause Pointer Authentication key signing mismatch errors + // when this feature is enabled for kernel code. + ptrauth_switch_to_hyp x1, x2, x3, x4, x5 + + // mte_switch_to_hyp(g_ctxt, h_ctxt, reg1) + mte_switch_to_hyp x1, x2, x3 + + // Restore hyp's sp_el0 + restore_sp_el0 x2, x3 + + // Now restore the hyp regs restore_callee_saved_regs x2 + set_loaded_vcpu xzr, x2, x3 + alternative_if ARM64_HAS_RAS_EXTN // If we have the RAS extensions we can consume a pending error - // without an unmask-SError and isb. - esb + // without an unmask-SError and isb. The ESB-instruction consumed any + // pending guest error when we took the exception from the guest. mrs_s x2, SYS_DISR_EL1 str x2, [x1, #(VCPU_FAULT_DISR - VCPU_CONTEXT)] cbz x2, 1f @@ -132,8 +181,16 @@ alternative_if ARM64_HAS_RAS_EXTN orr x0, x0, #(1<<ARM_EXIT_WITH_SERROR_BIT) 1: ret alternative_else - // If we have a pending asynchronous abort, now is the - // time to find out. From your VAXorcist book, page 666: + dsb sy // Synchronize against in-flight ld/st + isb // Prevent an early read of side-effect free ISR + mrs x2, isr_el1 + tbnz x2, #ISR_EL1_A_SHIFT, 2f + ret + nop +2: +alternative_endif + // We know we have a pending asynchronous abort, now is the + // time to flush it out. From your VAXorcist book, page 666: // "Threaten me not, oh Evil one! For I speak with // the power of DEC, and I command thee to show thyself!" mrs x2, elr_el2 @@ -141,29 +198,31 @@ alternative_else mrs x4, spsr_el2 mov x5, x0 - dsb sy // Synchronize against in-flight ld/st - nop msr daifclr, #4 // Unmask aborts -alternative_endif // This is our single instruction exception window. A pending // SError is guaranteed to occur at the earliest when we unmask // it, and at the latest just after the ISB. - .global abort_guest_exit_start abort_guest_exit_start: isb - .global abort_guest_exit_end abort_guest_exit_end: - // If the exception took place, restore the EL1 exception - // context so that we can report some information. - // Merge the exception code with the SError pending bit. - tbz x0, #ARM_EXIT_WITH_SERROR_BIT, 1f + msr daifset, #4 // Mask aborts + ret + + _kvm_extable abort_guest_exit_start, 9997f + _kvm_extable abort_guest_exit_end, 9997f +9997: + msr daifset, #4 // Mask aborts + mov x0, #(1 << ARM_EXIT_WITH_SERROR_BIT) + + // restore the EL1 exception context so that we can report some + // information. Merge the exception code with the SError pending bit. msr elr_el2, x2 msr esr_el2, x3 msr spsr_el2, x4 orr x0, x0, x5 1: ret -ENDPROC(__guest_exit) +SYM_FUNC_END(__guest_enter) |