arch/arm64/kvm/hyp/switch.c - kernel/msm-4.9 - Gitiles

 /*
  * 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/types.h>
 #include <linux/jump_label.h>
 #include <uapi/linux/psci.h>

 #include <kvm/arm_psci.h>

 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>

 static bool __hyp_text __fpsimd_enabled_nvhe(void)
 {
 	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
 }

 static bool __hyp_text __fpsimd_enabled_vhe(void)
 {
 	return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN);
 }

 static hyp_alternate_select(__fpsimd_is_enabled,
 			    __fpsimd_enabled_nvhe, __fpsimd_enabled_vhe,
 			    ARM64_HAS_VIRT_HOST_EXTN);

 bool __hyp_text __fpsimd_enabled(void)
 {
 	return __fpsimd_is_enabled()();
 }

 static void __hyp_text __activate_traps_vhe(void)
 {
 	u64 val;

 	val = read_sysreg(cpacr_el1);
 	val |= CPACR_EL1_TTA;
 	val &= ~CPACR_EL1_FPEN;
 	write_sysreg(val, cpacr_el1);

 	write_sysreg(kvm_get_hyp_vector(), vbar_el1);
 }

 static void __hyp_text __activate_traps_nvhe(void)
 {
 	u64 val;

 	val = CPTR_EL2_DEFAULT;
 	val |= CPTR_EL2_TTA | CPTR_EL2_TFP;
 	write_sysreg(val, cptr_el2);
 }

 static hyp_alternate_select(__activate_traps_arch,
 			    __activate_traps_nvhe, __activate_traps_vhe,
 			    ARM64_HAS_VIRT_HOST_EXTN);

 static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
 {
 	u64 val;

 	/*
 	 * We are about to set CPTR_EL2.TFP to trap all floating point
 	 * register accesses to EL2, however, the ARM ARM clearly states that
 	 * traps are only taken to EL2 if the operation would not otherwise
 	 * trap to EL1.  Therefore, always make sure that for 32-bit guests,
 	 * we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
 	 */
 	val = vcpu->arch.hcr_el2;
 	if (!(val & HCR_RW)) {
 		write_sysreg(1 << 30, fpexc32_el2);
 		isb();
 	}
 	write_sysreg(val, hcr_el2);
 	/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
 	write_sysreg(1 << 15, hstr_el2);
 	/*
 	 * Make sure we trap PMU access from EL0 to EL2. Also sanitize
 	 * PMSELR_EL0 to make sure it never contains the cycle
 	 * counter, which could make a PMXEVCNTR_EL0 access UNDEF at
 	 * EL1 instead of being trapped to EL2.
 	 */
 	write_sysreg(0, pmselr_el0);
 	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
 	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
 	__activate_traps_arch()();
 }

 static void __hyp_text __deactivate_traps_vhe(void)
 {
 	extern char vectors[];	/* kernel exception vectors */

 	write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
 	write_sysreg(CPACR_EL1_FPEN, cpacr_el1);
 	write_sysreg(vectors, vbar_el1);
 }

 static void __hyp_text __deactivate_traps_nvhe(void)
 {
 	write_sysreg(HCR_RW, hcr_el2);
 	write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
 }

 static hyp_alternate_select(__deactivate_traps_arch,
 			    __deactivate_traps_nvhe, __deactivate_traps_vhe,
 			    ARM64_HAS_VIRT_HOST_EXTN);

 static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
 {
 	/*
 	 * If we pended a virtual abort, preserve it until it gets
 	 * cleared. See D1.14.3 (Virtual Interrupts) for details, but
 	 * the crucial bit is "On taking a vSError interrupt,
 	 * HCR_EL2.VSE is cleared to 0."
 	 */
 	if (vcpu->arch.hcr_el2 & HCR_VSE)
 		vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);

 	__deactivate_traps_arch()();
 	write_sysreg(0, hstr_el2);
 	write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
 	write_sysreg(0, pmuserenr_el0);
 }

 static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
 {
 	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
 	write_sysreg(kvm->arch.vttbr, vttbr_el2);
 }

 static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
 {
 	write_sysreg(0, vttbr_el2);
 }

 static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
 {
 	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 		__vgic_v3_save_state(vcpu);
 	else
 		__vgic_v2_save_state(vcpu);

 	write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
 }

 static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
 {
 	u64 val;

 	val = read_sysreg(hcr_el2);
 	val |= 	HCR_INT_OVERRIDE;
 	val |= vcpu->arch.irq_lines;
 	write_sysreg(val, hcr_el2);

 	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 		__vgic_v3_restore_state(vcpu);
 	else
 		__vgic_v2_restore_state(vcpu);
 }

 static bool __hyp_text __true_value(void)
 {
 	return true;
 }

 static bool __hyp_text __false_value(void)
 {
 	return false;
 }

 static hyp_alternate_select(__check_arm_834220,
 			    __false_value, __true_value,
 			    ARM64_WORKAROUND_834220);

 static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
 {
 	u64 par, tmp;

 	/*
 	 * 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.
 	 *
 	 * We do need to save/restore PAR_EL1 though, as we haven't
 	 * saved the guest context yet, and we may return early...
 	 */
 	par = read_sysreg(par_el1);
 	asm volatile("at s1e1r, %0" : : "r" (far));
 	isb();

 	tmp = read_sysreg(par_el1);
 	write_sysreg(par, par_el1);

 	if (unlikely(tmp & 1))
 		return false; /* Translation failed, back to guest */

 	/* Convert PAR to HPFAR format */
 	*hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4;
 	return true;
 }

 static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
 {
 	u64 esr = read_sysreg_el2(esr);
 	u8 ec = ESR_ELx_EC(esr);
 	u64 hpfar, far;

 	vcpu->arch.fault.esr_el2 = esr;

 	if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
 		return true;

 	far = read_sysreg_el2(far);

 	/*
 	 * The HPFAR can be invalid if the stage 2 fault did not
 	 * happen during a stage 1 page table walk (the ESR_EL2.S1PTW
 	 * bit is clear) and one of the two following cases are true:
 	 *   1. The fault was due to a permission fault
 	 *   2. The processor carries errata 834220
 	 *
 	 * Therefore, for all non S1PTW faults where we either have a
 	 * permission fault or the errata workaround is enabled, we
 	 * resolve the IPA using the AT instruction.
 	 */
 	if (!(esr & ESR_ELx_S1PTW) &&
 	    (__check_arm_834220()() || (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
 		if (!__translate_far_to_hpfar(far, &hpfar))
 			return false;
 	} else {
 		hpfar = read_sysreg(hpfar_el2);
 	}

 	vcpu->arch.fault.far_el2 = far;
 	vcpu->arch.fault.hpfar_el2 = hpfar;
 	return true;
 }

 static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
 {
 	*vcpu_pc(vcpu) = read_sysreg_el2(elr);

 	if (vcpu_mode_is_32bit(vcpu)) {
 		vcpu->arch.ctxt.gp_regs.regs.pstate = read_sysreg_el2(spsr);
 		kvm_skip_instr32(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
 		write_sysreg_el2(vcpu->arch.ctxt.gp_regs.regs.pstate, spsr);
 	} else {
 		*vcpu_pc(vcpu) += 4;
 	}

 	write_sysreg_el2(*vcpu_pc(vcpu), elr);
 }

 int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 {
 	struct kvm_cpu_context *host_ctxt;
 	struct kvm_cpu_context *guest_ctxt;
 	bool fp_enabled;
 	u64 exit_code;

 	vcpu = kern_hyp_va(vcpu);
 	write_sysreg(vcpu, tpidr_el2);

 	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 	guest_ctxt = &vcpu->arch.ctxt;

 	__sysreg_save_host_state(host_ctxt);
 	__debug_cond_save_host_state(vcpu);

 	__activate_traps(vcpu);
 	__activate_vm(vcpu);

 	__vgic_restore_state(vcpu);
 	__timer_restore_state(vcpu);

 	/*
 	 * We must restore the 32-bit state before the sysregs, thanks
 	 * to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
 	 */
 	__sysreg32_restore_state(vcpu);
 	__sysreg_restore_guest_state(guest_ctxt);
 	__debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);

 	/* Jump in the fire! */
 again:
 	exit_code = __guest_enter(vcpu, host_ctxt);
 	/* And we're baaack! */

 	/*
 	 * We're using the raw exception code in order to only process
 	 * the trap if no SError is pending. We will come back to the
 	 * same PC once the SError has been injected, and replay the
 	 * trapping instruction.
 	 */
 	if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
 		goto again;

 	if (exit_code == ARM_EXCEPTION_TRAP &&
 	    (kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 ||
 	     kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32)) {
 		u32 val = vcpu_get_reg(vcpu, 0);

 		if (val == PSCI_0_2_FN_PSCI_VERSION) {
 			val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
 			if (unlikely(val == KVM_ARM_PSCI_0_1))
 				val = PSCI_RET_NOT_SUPPORTED;
 			vcpu_set_reg(vcpu, 0, val);
 			goto again;
 		}
 	}

 	if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
 	    exit_code == ARM_EXCEPTION_TRAP) {
 		bool valid;

 		valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
 			kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
 			kvm_vcpu_dabt_isvalid(vcpu) &&
 			!kvm_vcpu_dabt_isextabt(vcpu) &&
 			!kvm_vcpu_dabt_iss1tw(vcpu);

 		if (valid) {
 			int ret = __vgic_v2_perform_cpuif_access(vcpu);

 			if (ret == 1) {
 				__skip_instr(vcpu);
 				goto again;
 			}

 			if (ret == -1) {
 				/* Promote an illegal access to an SError */
 				__skip_instr(vcpu);
 				exit_code = ARM_EXCEPTION_EL1_SERROR;
 			}

 			/* 0 falls through to be handler out of EL2 */
 		}
 	}

 	fp_enabled = __fpsimd_enabled();

 	__sysreg_save_guest_state(guest_ctxt);
 	__sysreg32_save_state(vcpu);
 	__timer_save_state(vcpu);
 	__vgic_save_state(vcpu);

 	__deactivate_traps(vcpu);
 	__deactivate_vm(vcpu);

 	__sysreg_restore_host_state(host_ctxt);

 	if (fp_enabled) {
 		__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
 		__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
 	}

 	__debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
 	__debug_cond_restore_host_state(vcpu);

 	return exit_code;
 }

 static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";

 static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par)
 {
 	unsigned long str_va;

 	/*
 	 * Force the panic string to be loaded from the literal pool,
 	 * making sure it is a kernel address and not a PC-relative
 	 * reference.
 	 */
 	asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va));

 	__hyp_do_panic(str_va,
 		       spsr,  elr,
 		       read_sysreg(esr_el2),   read_sysreg_el2(far),
 		       read_sysreg(hpfar_el2), par,
 		       (void *)read_sysreg(tpidr_el2));
 }

 static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par)
 {
 	panic(__hyp_panic_string,
 	      spsr,  elr,
 	      read_sysreg_el2(esr),   read_sysreg_el2(far),
 	      read_sysreg(hpfar_el2), par,
 	      (void *)read_sysreg(tpidr_el2));
 }

 static hyp_alternate_select(__hyp_call_panic,
 			    __hyp_call_panic_nvhe, __hyp_call_panic_vhe,
 			    ARM64_HAS_VIRT_HOST_EXTN);

 void __hyp_text __noreturn __hyp_panic(void)
 {
 	u64 spsr = read_sysreg_el2(spsr);
 	u64 elr = read_sysreg_el2(elr);
 	u64 par = read_sysreg(par_el1);

 	if (read_sysreg(vttbr_el2)) {
 		struct kvm_vcpu *vcpu;
 		struct kvm_cpu_context *host_ctxt;

 		vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
 		host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
 		__timer_save_state(vcpu);
 		__deactivate_traps(vcpu);
 		__deactivate_vm(vcpu);
 		__sysreg_restore_host_state(host_ctxt);
 	}

 	/* Call panic for real */
 	__hyp_call_panic()(spsr, elr, par);

 	unreachable();
 }
	/*
	* 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/types.h>
	#include <linux/jump_label.h>
	#include <uapi/linux/psci.h>

	#include <kvm/arm_psci.h>

	#include <asm/kvm_asm.h>
	#include <asm/kvm_emulate.h>
	#include <asm/kvm_hyp.h>

	static bool __hyp_text __fpsimd_enabled_nvhe(void)
	{
	return !(read_sysreg(cptr_el2) & CPTR_EL2_TFP);
	}

	static bool __hyp_text __fpsimd_enabled_vhe(void)
	{
	return !!(read_sysreg(cpacr_el1) & CPACR_EL1_FPEN);
	}

	static hyp_alternate_select(__fpsimd_is_enabled,
	__fpsimd_enabled_nvhe, __fpsimd_enabled_vhe,
	ARM64_HAS_VIRT_HOST_EXTN);

	bool __hyp_text __fpsimd_enabled(void)
	{
	return __fpsimd_is_enabled()();
	}

	static void __hyp_text __activate_traps_vhe(void)
	{
	u64 val;

	val = read_sysreg(cpacr_el1);
	val \|= CPACR_EL1_TTA;
	val &= ~CPACR_EL1_FPEN;
	write_sysreg(val, cpacr_el1);

	write_sysreg(kvm_get_hyp_vector(), vbar_el1);
	}

	static void __hyp_text __activate_traps_nvhe(void)
	{
	u64 val;

	val = CPTR_EL2_DEFAULT;
	val \|= CPTR_EL2_TTA \| CPTR_EL2_TFP;
	write_sysreg(val, cptr_el2);
	}

	static hyp_alternate_select(__activate_traps_arch,
	__activate_traps_nvhe, __activate_traps_vhe,
	ARM64_HAS_VIRT_HOST_EXTN);

	static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
	{
	u64 val;

	/*
	* We are about to set CPTR_EL2.TFP to trap all floating point
	* register accesses to EL2, however, the ARM ARM clearly states that
	* traps are only taken to EL2 if the operation would not otherwise
	* trap to EL1. Therefore, always make sure that for 32-bit guests,
	* we set FPEXC.EN to prevent traps to EL1, when setting the TFP bit.
	*/
	val = vcpu->arch.hcr_el2;
	if (!(val & HCR_RW)) {
	write_sysreg(1 << 30, fpexc32_el2);
	isb();
	}
	write_sysreg(val, hcr_el2);
	/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
	write_sysreg(1 << 15, hstr_el2);
	/*
	* Make sure we trap PMU access from EL0 to EL2. Also sanitize
	* PMSELR_EL0 to make sure it never contains the cycle
	* counter, which could make a PMXEVCNTR_EL0 access UNDEF at
	* EL1 instead of being trapped to EL2.
	*/
	write_sysreg(0, pmselr_el0);
	write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
	write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
	__activate_traps_arch()();
	}

	static void __hyp_text __deactivate_traps_vhe(void)
	{
	extern char vectors[]; /* kernel exception vectors */

	write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
	write_sysreg(CPACR_EL1_FPEN, cpacr_el1);
	write_sysreg(vectors, vbar_el1);
	}

	static void __hyp_text __deactivate_traps_nvhe(void)
	{
	write_sysreg(HCR_RW, hcr_el2);
	write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
	}

	static hyp_alternate_select(__deactivate_traps_arch,
	__deactivate_traps_nvhe, __deactivate_traps_vhe,
	ARM64_HAS_VIRT_HOST_EXTN);

	static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
	{
	/*
	* If we pended a virtual abort, preserve it until it gets
	* cleared. See D1.14.3 (Virtual Interrupts) for details, but
	* the crucial bit is "On taking a vSError interrupt,
	* HCR_EL2.VSE is cleared to 0."
	*/
	if (vcpu->arch.hcr_el2 & HCR_VSE)
	vcpu->arch.hcr_el2 = read_sysreg(hcr_el2);

	__deactivate_traps_arch()();
	write_sysreg(0, hstr_el2);
	write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
	write_sysreg(0, pmuserenr_el0);
	}

	static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
	{
	struct kvm *kvm = kern_hyp_va(vcpu->kvm);
	write_sysreg(kvm->arch.vttbr, vttbr_el2);
	}

	static void __hyp_text __deactivate_vm(struct kvm_vcpu *vcpu)
	{
	write_sysreg(0, vttbr_el2);
	}

	static void __hyp_text __vgic_save_state(struct kvm_vcpu *vcpu)
	{
	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
	__vgic_v3_save_state(vcpu);
	else
	__vgic_v2_save_state(vcpu);

	write_sysreg(read_sysreg(hcr_el2) & ~HCR_INT_OVERRIDE, hcr_el2);
	}

	static void __hyp_text __vgic_restore_state(struct kvm_vcpu *vcpu)
	{
	u64 val;

	val = read_sysreg(hcr_el2);
	val \|= HCR_INT_OVERRIDE;
	val \|= vcpu->arch.irq_lines;
	write_sysreg(val, hcr_el2);

	if (static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
	__vgic_v3_restore_state(vcpu);
	else
	__vgic_v2_restore_state(vcpu);
	}

	static bool __hyp_text __true_value(void)
	{
	return true;
	}

	static bool __hyp_text __false_value(void)
	{
	return false;
	}

	static hyp_alternate_select(__check_arm_834220,
	__false_value, __true_value,
	ARM64_WORKAROUND_834220);

	static bool __hyp_text __translate_far_to_hpfar(u64 far, u64 *hpfar)
	{
	u64 par, tmp;

	/*
	* 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.
	*
	* We do need to save/restore PAR_EL1 though, as we haven't
	* saved the guest context yet, and we may return early...
	*/
	par = read_sysreg(par_el1);
	asm volatile("at s1e1r, %0" : : "r" (far));
	isb();

	tmp = read_sysreg(par_el1);
	write_sysreg(par, par_el1);

	if (unlikely(tmp & 1))
	return false; /* Translation failed, back to guest */

	/* Convert PAR to HPFAR format */
	*hpfar = ((tmp >> 12) & ((1UL << 36) - 1)) << 4;
	return true;
	}

	static bool __hyp_text __populate_fault_info(struct kvm_vcpu *vcpu)
	{
	u64 esr = read_sysreg_el2(esr);
	u8 ec = ESR_ELx_EC(esr);
	u64 hpfar, far;

	vcpu->arch.fault.esr_el2 = esr;

	if (ec != ESR_ELx_EC_DABT_LOW && ec != ESR_ELx_EC_IABT_LOW)
	return true;

	far = read_sysreg_el2(far);

	/*
	* The HPFAR can be invalid if the stage 2 fault did not
	* happen during a stage 1 page table walk (the ESR_EL2.S1PTW
	* bit is clear) and one of the two following cases are true:
	* 1. The fault was due to a permission fault
	* 2. The processor carries errata 834220
	*
	* Therefore, for all non S1PTW faults where we either have a
	* permission fault or the errata workaround is enabled, we
	* resolve the IPA using the AT instruction.
	*/
	if (!(esr & ESR_ELx_S1PTW) &&
	(__check_arm_834220()() \|\| (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
	if (!__translate_far_to_hpfar(far, &hpfar))
	return false;
	} else {
	hpfar = read_sysreg(hpfar_el2);
	}

	vcpu->arch.fault.far_el2 = far;
	vcpu->arch.fault.hpfar_el2 = hpfar;
	return true;
	}

	static void __hyp_text __skip_instr(struct kvm_vcpu *vcpu)
	{
	*vcpu_pc(vcpu) = read_sysreg_el2(elr);

	if (vcpu_mode_is_32bit(vcpu)) {
	vcpu->arch.ctxt.gp_regs.regs.pstate = read_sysreg_el2(spsr);
	kvm_skip_instr32(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
	write_sysreg_el2(vcpu->arch.ctxt.gp_regs.regs.pstate, spsr);
	} else {
	*vcpu_pc(vcpu) += 4;
	}

	write_sysreg_el2(*vcpu_pc(vcpu), elr);
	}

	int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu)
	{
	struct kvm_cpu_context *host_ctxt;
	struct kvm_cpu_context *guest_ctxt;
	bool fp_enabled;
	u64 exit_code;

	vcpu = kern_hyp_va(vcpu);
	write_sysreg(vcpu, tpidr_el2);

	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
	guest_ctxt = &vcpu->arch.ctxt;

	__sysreg_save_host_state(host_ctxt);
	__debug_cond_save_host_state(vcpu);

	__activate_traps(vcpu);
	__activate_vm(vcpu);

	__vgic_restore_state(vcpu);
	__timer_restore_state(vcpu);

	/*
	* We must restore the 32-bit state before the sysregs, thanks
	* to erratum #852523 (Cortex-A57) or #853709 (Cortex-A72).
	*/
	__sysreg32_restore_state(vcpu);
	__sysreg_restore_guest_state(guest_ctxt);
	__debug_restore_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);

	/* Jump in the fire! */
	again:
	exit_code = __guest_enter(vcpu, host_ctxt);
	/* And we're baaack! */

	/*
	* We're using the raw exception code in order to only process
	* the trap if no SError is pending. We will come back to the
	* same PC once the SError has been injected, and replay the
	* trapping instruction.
	*/
	if (exit_code == ARM_EXCEPTION_TRAP && !__populate_fault_info(vcpu))
	goto again;

	if (exit_code == ARM_EXCEPTION_TRAP &&
	(kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC64 \|\|
	kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_HVC32)) {
	u32 val = vcpu_get_reg(vcpu, 0);

	if (val == PSCI_0_2_FN_PSCI_VERSION) {
	val = kvm_psci_version(vcpu, kern_hyp_va(vcpu->kvm));
	if (unlikely(val == KVM_ARM_PSCI_0_1))
	val = PSCI_RET_NOT_SUPPORTED;
	vcpu_set_reg(vcpu, 0, val);
	goto again;
	}
	}

	if (static_branch_unlikely(&vgic_v2_cpuif_trap) &&
	exit_code == ARM_EXCEPTION_TRAP) {
	bool valid;

	valid = kvm_vcpu_trap_get_class(vcpu) == ESR_ELx_EC_DABT_LOW &&
	kvm_vcpu_trap_get_fault_type(vcpu) == FSC_FAULT &&
	kvm_vcpu_dabt_isvalid(vcpu) &&
	!kvm_vcpu_dabt_isextabt(vcpu) &&
	!kvm_vcpu_dabt_iss1tw(vcpu);

	if (valid) {
	int ret = __vgic_v2_perform_cpuif_access(vcpu);

	if (ret == 1) {
	__skip_instr(vcpu);
	goto again;
	}

	if (ret == -1) {
	/* Promote an illegal access to an SError */
	__skip_instr(vcpu);
	exit_code = ARM_EXCEPTION_EL1_SERROR;
	}

	/* 0 falls through to be handler out of EL2 */
	}
	}

	fp_enabled = __fpsimd_enabled();

	__sysreg_save_guest_state(guest_ctxt);
	__sysreg32_save_state(vcpu);
	__timer_save_state(vcpu);
	__vgic_save_state(vcpu);

	__deactivate_traps(vcpu);
	__deactivate_vm(vcpu);

	__sysreg_restore_host_state(host_ctxt);

	if (fp_enabled) {
	__fpsimd_save_state(&guest_ctxt->gp_regs.fp_regs);
	__fpsimd_restore_state(&host_ctxt->gp_regs.fp_regs);
	}

	__debug_save_state(vcpu, kern_hyp_va(vcpu->arch.debug_ptr), guest_ctxt);
	__debug_cond_restore_host_state(vcpu);

	return exit_code;
	}

	static const char __hyp_panic_string[] = "HYP panic:\nPS:%08llx PC:%016llx ESR:%08llx\nFAR:%016llx HPFAR:%016llx PAR:%016llx\nVCPU:%p\n";

	static void __hyp_text __hyp_call_panic_nvhe(u64 spsr, u64 elr, u64 par)
	{
	unsigned long str_va;

	/*
	* Force the panic string to be loaded from the literal pool,
	* making sure it is a kernel address and not a PC-relative
	* reference.
	*/
	asm volatile("ldr %0, =__hyp_panic_string" : "=r" (str_va));

	__hyp_do_panic(str_va,
	spsr, elr,
	read_sysreg(esr_el2), read_sysreg_el2(far),
	read_sysreg(hpfar_el2), par,
	(void *)read_sysreg(tpidr_el2));
	}

	static void __hyp_text __hyp_call_panic_vhe(u64 spsr, u64 elr, u64 par)
	{
	panic(__hyp_panic_string,
	spsr, elr,
	read_sysreg_el2(esr), read_sysreg_el2(far),
	read_sysreg(hpfar_el2), par,
	(void *)read_sysreg(tpidr_el2));
	}

	static hyp_alternate_select(__hyp_call_panic,
	__hyp_call_panic_nvhe, __hyp_call_panic_vhe,
	ARM64_HAS_VIRT_HOST_EXTN);

	void __hyp_text __noreturn __hyp_panic(void)
	{
	u64 spsr = read_sysreg_el2(spsr);
	u64 elr = read_sysreg_el2(elr);
	u64 par = read_sysreg(par_el1);

	if (read_sysreg(vttbr_el2)) {
	struct kvm_vcpu *vcpu;
	struct kvm_cpu_context *host_ctxt;

	vcpu = (struct kvm_vcpu *)read_sysreg(tpidr_el2);
	host_ctxt = kern_hyp_va(vcpu->arch.host_cpu_context);
	__timer_save_state(vcpu);
	__deactivate_traps(vcpu);
	__deactivate_vm(vcpu);
	__sysreg_restore_host_state(host_ctxt);
	}

	/* Call panic for real */
	__hyp_call_panic()(spsr, elr, par);

	unreachable();
	}