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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2015 - ARM Ltd
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#include <linux/linkage.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>
#include <asm/kvm_ptrauth.h>
.text
/*
* u64 __guest_enter(struct kvm_vcpu *vcpu);
*/
SYM_FUNC_START(__guest_enter)
// x0: vcpu
// x1-x17: clobbered by macros
// x29: guest context
adr_this_cpu x1, kvm_hyp_ctxt, x2
// Store the hyp regs
save_callee_saved_regs x1
// 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
mov x0, #ARM_EXCEPTION_IRQ
ret
1:
set_loaded_vcpu x0, x1, x2
add x29, x0, #VCPU_CONTEXT
// 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, [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
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
// vcpu x0-x1 on the stack
add x1, x1, #VCPU_CONTEXT
ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
// Store the guest regs x2 and x3
stp x2, x3, [x1, #CPU_XREG_OFFSET(2)]
// Retrieve the guest regs x0-x1 from the stack
ldp x2, x3, [sp], #16 // x0, x1
// 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)]
stp x8, x9, [x1, #CPU_XREG_OFFSET(8)]
stp x10, x11, [x1, #CPU_XREG_OFFSET(10)]
stp x12, x13, [x1, #CPU_XREG_OFFSET(12)]
stp x14, x15, [x1, #CPU_XREG_OFFSET(14)]
stp x16, x17, [x1, #CPU_XREG_OFFSET(16)]
// Store the guest regs x18-x29, lr
save_callee_saved_regs x1
// Store the guest's sp_el0
save_sp_el0 x1, x2
adr_this_cpu x2, kvm_hyp_ctxt, x3
// 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
// 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. 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
msr_s SYS_DISR_EL1, xzr
orr x0, x0, #(1<<ARM_EXIT_WITH_SERROR_BIT)
1: ret
alternative_else
dsb sy // Synchronize against in-flight ld/st
isb // Prevent an early read of side-effect free ISR
mrs x2, isr_el1
tbnz x2, #8, 2f // ISR_EL1.A
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
mrs x3, esr_el2
mrs x4, spsr_el2
mov x5, x0
msr daifclr, #4 // Unmask aborts
// 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.
abort_guest_exit_start:
isb
abort_guest_exit_end:
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
SYM_FUNC_END(__guest_enter)
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