arch/arm64/kvm/hyp/include/hyp/fault.h

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#ifndef __ARM64_KVM_HYP_FAULT_H__
#define __ARM64_KVM_HYP_FAULT_H__

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

static inline bool __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();
	if (!__kvm_at("s1e1r", far))
		tmp = read_sysreg_par();
	else
		tmp = SYS_PAR_EL1_F; /* back to the guest */
	write_sysreg(par, par_el1);

	if (unlikely(tmp & SYS_PAR_EL1_F))
		return false; /* Translation failed, back to guest */

	/* Convert PAR to HPFAR format */
	*hpfar = PAR_TO_HPFAR(tmp);
	return true;
}

static inline bool __get_fault_info(u64 esr, struct kvm_vcpu_fault_info *fault)
{
	u64 hpfar, far;

	far = read_sysreg_el2(SYS_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) &&
	    (cpus_have_final_cap(ARM64_WORKAROUND_834220) ||
	     (esr & ESR_ELx_FSC_TYPE) == FSC_PERM)) {
		if (!__translate_far_to_hpfar(far, &hpfar))
			return false;
	} else {
		hpfar = read_sysreg(hpfar_el2);
	}

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

#endif