/*
   * Copyright (C) 2012,2013 - ARM Ltd
   * Author: Marc Zyngier <marc.zyngier@arm.com>
   *
   * Derived from arch/arm/kvm/guest.c:
   * Copyright (C) 2012 - Virtual Open Systems and Columbia University
   * Author: Christoffer Dall <c.dall@virtualopensystems.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/errno.h>
  #include <linux/err.h>
  #include <linux/kvm_host.h>
  #include <linux/module.h>
  #include <linux/vmalloc.h>
  #include <linux/fs.h>
  #include <asm/cputype.h>
  #include <asm/uaccess.h>
  #include <asm/kvm.h>
  #include <asm/kvm_asm.h>
  #include <asm/kvm_emulate.h>
  #include <asm/kvm_coproc.h>
  
  struct kvm_stats_debugfs_item debugfs_entries[] = {
  	{ NULL }
  };
  
  int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
  {
  	vcpu->arch.hcr_el2 = HCR_GUEST_FLAGS;
  	return 0;
  }
  
  static u64 core_reg_offset_from_id(u64 id)
  {
  	return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
  }
  
  static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
  {
  	/*
  	 * Because the kvm_regs structure is a mix of 32, 64 and
  	 * 128bit fields, we index it as if it was a 32bit
  	 * array. Hence below, nr_regs is the number of entries, and
  	 * off the index in the "array".
  	 */
  	__u32 __user *uaddr = (__u32 __user *)(unsigned long)reg->addr;
  	struct kvm_regs *regs = vcpu_gp_regs(vcpu);
  	int nr_regs = sizeof(*regs) / sizeof(__u32);
  	u32 off;
  
  	/* Our ID is an index into the kvm_regs struct. */
  	off = core_reg_offset_from_id(reg->id);
  	if (off >= nr_regs ||
  	    (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
  		return -ENOENT;
  
  	if (copy_to_user(uaddr, ((u32 *)regs) + off, KVM_REG_SIZE(reg->id)))
  		return -EFAULT;
  
  	return 0;
  }
  
  static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
  {
  	__u32 __user *uaddr = (__u32 __user *)(unsigned long)reg->addr;
  	struct kvm_regs *regs = vcpu_gp_regs(vcpu);
  	int nr_regs = sizeof(*regs) / sizeof(__u32);
  	__uint128_t tmp;
  	void *valp = &tmp;
  	u64 off;
  	int err = 0;
  
  	/* Our ID is an index into the kvm_regs struct. */
  	off = core_reg_offset_from_id(reg->id);
  	if (off >= nr_regs ||
  	    (off + (KVM_REG_SIZE(reg->id) / sizeof(__u32))) >= nr_regs)
  		return -ENOENT;
  
  	if (KVM_REG_SIZE(reg->id) > sizeof(tmp))
  		return -EINVAL;
  
  	if (copy_from_user(valp, uaddr, KVM_REG_SIZE(reg->id))) {
  		err = -EFAULT;
  		goto out;
  	}
  
  	if (off == KVM_REG_ARM_CORE_REG(regs.pstate)) {
  		u32 mode = (*(u32 *)valp) & COMPAT_PSR_MODE_MASK;
  		switch (mode) {
  		case COMPAT_PSR_MODE_USR:
  		case COMPAT_PSR_MODE_FIQ:
  		case COMPAT_PSR_MODE_IRQ:
  		case COMPAT_PSR_MODE_SVC:
  		case COMPAT_PSR_MODE_ABT:
  		case COMPAT_PSR_MODE_UND:
  		case PSR_MODE_EL0t:
  		case PSR_MODE_EL1t:
  		case PSR_MODE_EL1h:
  			break;
  		default:
  			err = -EINVAL;
  			goto out;
  		}
  	}
  
  	memcpy((u32 *)regs + off, valp, KVM_REG_SIZE(reg->id));
  out:
  	return err;
  }
  
  int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
  {
  	return -EINVAL;
  }
  
  int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
  {
  	return -EINVAL;
  }
  
  static unsigned long num_core_regs(void)
  {
  	return sizeof(struct kvm_regs) / sizeof(__u32);
  }
  
  /**
   * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
   *
   * This is for all registers.
   */
  unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
  {
  	return num_core_regs() + kvm_arm_num_sys_reg_descs(vcpu);
  }
  
  /**
   * kvm_arm_copy_reg_indices - get indices of all registers.
   *
   * We do core registers right here, then we apppend system regs.
   */
  int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
  {
  	unsigned int i;
  	const u64 core_reg = KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_CORE;
  
  	for (i = 0; i < sizeof(struct kvm_regs) / sizeof(__u32); i++) {
  		if (put_user(core_reg | i, uindices))
  			return -EFAULT;
  		uindices++;
  	}
  
  	return kvm_arm_copy_sys_reg_indices(vcpu, uindices);
  }
  
  int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
  {
  	/* We currently use nothing arch-specific in upper 32 bits */
  	if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM64 >> 32)
  		return -EINVAL;
  
  	/* Register group 16 means we want a core register. */
  	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
  		return get_core_reg(vcpu, reg);
  
  	return kvm_arm_sys_reg_get_reg(vcpu, reg);
  }
  
  int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
  {
  	/* We currently use nothing arch-specific in upper 32 bits */
  	if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM64 >> 32)
  		return -EINVAL;
  
  	/* Register group 16 means we set a core register. */
  	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
  		return set_core_reg(vcpu, reg);
  
  	return kvm_arm_sys_reg_set_reg(vcpu, reg);
  }
  
  int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
  				  struct kvm_sregs *sregs)
  {
  	return -EINVAL;
  }
  
  int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
  				  struct kvm_sregs *sregs)
  {
  	return -EINVAL;
  }
  
  int __attribute_const__ kvm_target_cpu(void)
  {
  	unsigned long implementor = read_cpuid_implementor();
  	unsigned long part_number = read_cpuid_part_number();
  
  	switch (implementor) {
  	case ARM_CPU_IMP_ARM:
  		switch (part_number) {
  		case ARM_CPU_PART_AEM_V8:
  			return KVM_ARM_TARGET_AEM_V8;
  		case ARM_CPU_PART_FOUNDATION:
  			return KVM_ARM_TARGET_FOUNDATION_V8;
  		case ARM_CPU_PART_CORTEX_A57:
  			return KVM_ARM_TARGET_CORTEX_A57;
  		};
  		break;
  	case ARM_CPU_IMP_APM:
  		switch (part_number) {
  		case APM_CPU_PART_POTENZA:
  			return KVM_ARM_TARGET_XGENE_POTENZA;
  		};
  		break;
  	};
  
  	return -EINVAL;
  }
  
  int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
  			const struct kvm_vcpu_init *init)
  {
  	unsigned int i;
  	int phys_target = kvm_target_cpu();
  
  	if (init->target != phys_target)
  		return -EINVAL;
  
  	vcpu->arch.target = phys_target;
  	bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
  
  	/* -ENOENT for unknown features, -EINVAL for invalid combinations. */
  	for (i = 0; i < sizeof(init->features) * 8; i++) {
  		if (init->features[i / 32] & (1 << (i % 32))) {
  			if (i >= KVM_VCPU_MAX_FEATURES)
  				return -ENOENT;
  			set_bit(i, vcpu->arch.features);
  		}
  	}
  
  	/* Now we know what it is, we can reset it. */
  	return kvm_reset_vcpu(vcpu);
  }
  
  int kvm_vcpu_preferred_target(struct kvm_vcpu_init *init)
  {
  	int target = kvm_target_cpu();
  
  	if (target < 0)
  		return -ENODEV;
  
  	memset(init, 0, sizeof(*init));
  
  	/*
  	 * For now, we don't return any features.
  	 * In future, we might use features to return target
  	 * specific features available for the preferred
  	 * target type.
  	 */
  	init->target = (__u32)target;
  
  	return 0;
  }
  
  int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
  {
  	return -EINVAL;
  }
  
  int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
  {
  	return -EINVAL;
  }
  
  int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
  				  struct kvm_translation *tr)
  {
  	return -EINVAL;
  }