/*
 * 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/bits.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/nospec.h>
#include <linux/kernel.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/stddef.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <kvm/arm_psci.h>
#include <asm/cputype.h>
#include <linux/uaccess.h>
#include <asm/fpsimd.h>
#include <asm/kvm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/kvm_host.h>
#include <asm/sigcontext.h>

#include "trace.h"

#define VM_STAT(x) { #x, offsetof(struct kvm, stat.x), KVM_STAT_VM }
#define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }

struct kvm_stats_debugfs_item debugfs_entries[] = {
	VCPU_STAT(hvc_exit_stat),
	VCPU_STAT(wfe_exit_stat),
	VCPU_STAT(wfi_exit_stat),
	VCPU_STAT(mmio_exit_user),
	VCPU_STAT(mmio_exit_kernel),
	VCPU_STAT(exits),
	{ NULL }
};

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
	return 0;
}

static bool core_reg_offset_is_vreg(u64 off)
{
	return off >= KVM_REG_ARM_CORE_REG(fp_regs.vregs) &&
		off < KVM_REG_ARM_CORE_REG(fp_regs.fpsr);
}

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 validate_core_offset(const struct kvm_vcpu *vcpu,
				const struct kvm_one_reg *reg)
{
	u64 off = core_reg_offset_from_id(reg->id);
	int size;

	switch (off) {
	case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
	     KVM_REG_ARM_CORE_REG(regs.regs[30]):
	case KVM_REG_ARM_CORE_REG(regs.sp):
	case KVM_REG_ARM_CORE_REG(regs.pc):
	case KVM_REG_ARM_CORE_REG(regs.pstate):
	case KVM_REG_ARM_CORE_REG(sp_el1):
	case KVM_REG_ARM_CORE_REG(elr_el1):
	case KVM_REG_ARM_CORE_REG(spsr[0]) ...
	     KVM_REG_ARM_CORE_REG(spsr[KVM_NR_SPSR - 1]):
		size = sizeof(__u64);
		break;

	case KVM_REG_ARM_CORE_REG(fp_regs.vregs[0]) ...
	     KVM_REG_ARM_CORE_REG(fp_regs.vregs[31]):
		size = sizeof(__uint128_t);
		break;

	case KVM_REG_ARM_CORE_REG(fp_regs.fpsr):
	case KVM_REG_ARM_CORE_REG(fp_regs.fpcr):
		size = sizeof(__u32);
		break;

	default:
		return -EINVAL;
	}

	if (KVM_REG_SIZE(reg->id) != size ||
	    !IS_ALIGNED(off, size / sizeof(__u32)))
		return -EINVAL;

	/*
	 * The KVM_REG_ARM64_SVE regs must be used instead of
	 * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on
	 * SVE-enabled vcpus:
	 */
	if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(off))
		return -EINVAL;

	return 0;
}

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 (validate_core_offset(vcpu, reg))
		return -EINVAL;

	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 (validate_core_offset(vcpu, reg))
		return -EINVAL;

	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)) {
		u64 mode = (*(u64 *)valp) & PSR_AA32_MODE_MASK;
		switch (mode) {
		case PSR_AA32_MODE_USR:
			if (!system_supports_32bit_el0())
				return -EINVAL;
			break;
		case PSR_AA32_MODE_FIQ:
		case PSR_AA32_MODE_IRQ:
		case PSR_AA32_MODE_SVC:
		case PSR_AA32_MODE_ABT:
		case PSR_AA32_MODE_UND:
			if (!vcpu_el1_is_32bit(vcpu))
				return -EINVAL;
			break;
		case PSR_MODE_EL0t:
		case PSR_MODE_EL1t:
		case PSR_MODE_EL1h:
			if (vcpu_el1_is_32bit(vcpu))
				return -EINVAL;
			break;
		default:
			err = -EINVAL;
			goto out;
		}
	}

	memcpy((u32 *)regs + off, valp, KVM_REG_SIZE(reg->id));
out:
	return err;
}

#define SVE_REG_SLICE_SHIFT	0
#define SVE_REG_SLICE_BITS	5
#define SVE_REG_ID_SHIFT	(SVE_REG_SLICE_SHIFT + SVE_REG_SLICE_BITS)
#define SVE_REG_ID_BITS		5

#define SVE_REG_SLICE_MASK					\
	GENMASK(SVE_REG_SLICE_SHIFT + SVE_REG_SLICE_BITS - 1,	\
		SVE_REG_SLICE_SHIFT)
#define SVE_REG_ID_MASK							\
	GENMASK(SVE_REG_ID_SHIFT + SVE_REG_ID_BITS - 1, SVE_REG_ID_SHIFT)

#define SVE_NUM_SLICES (1 << SVE_REG_SLICE_BITS)

#define KVM_SVE_ZREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_ZREG(0, 0))
#define KVM_SVE_PREG_SIZE KVM_REG_SIZE(KVM_REG_ARM64_SVE_PREG(0, 0))

/* Bounds of a single SVE register slice within vcpu->arch.sve_state */
struct sve_state_reg_region {
	unsigned int koffset;	/* offset into sve_state in kernel memory */
	unsigned int klen;	/* length in kernel memory */
	unsigned int upad;	/* extra trailing padding in user memory */
};

/* Get sanitised bounds for user/kernel SVE register copy */
static int sve_reg_to_region(struct sve_state_reg_region *region,
			     struct kvm_vcpu *vcpu,
			     const struct kvm_one_reg *reg)
{
	/* reg ID ranges for Z- registers */
	const u64 zreg_id_min = KVM_REG_ARM64_SVE_ZREG(0, 0);
	const u64 zreg_id_max = KVM_REG_ARM64_SVE_ZREG(SVE_NUM_ZREGS - 1,
						       SVE_NUM_SLICES - 1);

	/* reg ID ranges for P- registers and FFR (which are contiguous) */
	const u64 preg_id_min = KVM_REG_ARM64_SVE_PREG(0, 0);
	const u64 preg_id_max = KVM_REG_ARM64_SVE_FFR(SVE_NUM_SLICES - 1);

	unsigned int vq;
	unsigned int reg_num;

	unsigned int reqoffset, reqlen; /* User-requested offset and length */
	unsigned int maxlen; /* Maxmimum permitted length */

	size_t sve_state_size;

	/* Only the first slice ever exists, for now: */
	if ((reg->id & SVE_REG_SLICE_MASK) != 0)
		return -ENOENT;

	vq = sve_vq_from_vl(vcpu->arch.sve_max_vl);

	reg_num = (reg->id & SVE_REG_ID_MASK) >> SVE_REG_ID_SHIFT;

	if (reg->id >= zreg_id_min && reg->id <= zreg_id_max) {
		reqoffset = SVE_SIG_ZREG_OFFSET(vq, reg_num) -
				SVE_SIG_REGS_OFFSET;
		reqlen = KVM_SVE_ZREG_SIZE;
		maxlen = SVE_SIG_ZREG_SIZE(vq);
	} else if (reg->id >= preg_id_min && reg->id <= preg_id_max) {
		reqoffset = SVE_SIG_PREG_OFFSET(vq, reg_num) -
				SVE_SIG_REGS_OFFSET;
		reqlen = KVM_SVE_PREG_SIZE;
		maxlen = SVE_SIG_PREG_SIZE(vq);
	} else {
		return -ENOENT;
	}

	sve_state_size = vcpu_sve_state_size(vcpu);
	if (!sve_state_size)
		return -EINVAL;

	region->koffset = array_index_nospec(reqoffset, sve_state_size);
	region->klen = min(maxlen, reqlen);
	region->upad = reqlen - region->klen;

	return 0;
}

static int get_sve_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
	struct sve_state_reg_region region;
	char __user *uptr = (char __user *)reg->addr;

	if (!vcpu_has_sve(vcpu) || sve_reg_to_region(&region, vcpu, reg))
		return -ENOENT;

	if (copy_to_user(uptr, vcpu->arch.sve_state + region.koffset,
			 region.klen) ||
	    clear_user(uptr + region.klen, region.upad))
		return -EFAULT;

	return 0;
}

static int set_sve_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
	struct sve_state_reg_region region;
	const char __user *uptr = (const char __user *)reg->addr;

	if (!vcpu_has_sve(vcpu) || sve_reg_to_region(&region, vcpu, reg))
		return -ENOENT;

	if (copy_from_user(vcpu->arch.sve_state + region.koffset, uptr,
			   region.klen))
		return -EFAULT;

	return 0;
}

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 int copy_core_reg_indices(const struct kvm_vcpu *vcpu,
				 u64 __user *uindices)
{
	unsigned int i;
	int n = 0;
	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++) {
		/*
		 * The KVM_REG_ARM64_SVE regs must be used instead of
		 * KVM_REG_ARM_CORE for accessing the FPSIMD V-registers on
		 * SVE-enabled vcpus:
		 */
		if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(i))
			continue;

		if (uindices) {
			if (put_user(core_reg | i, uindices))
				return -EFAULT;
			uindices++;
		}

		n++;
	}

	return n;
}

static unsigned long num_core_regs(const struct kvm_vcpu *vcpu)
{
	return copy_core_reg_indices(vcpu, NULL);
}

/**
 * ARM64 versions of the TIMER registers, always available on arm64
 */

#define NUM_TIMER_REGS 3

static bool is_timer_reg(u64 index)
{
	switch (index) {
	case KVM_REG_ARM_TIMER_CTL:
	case KVM_REG_ARM_TIMER_CNT:
	case KVM_REG_ARM_TIMER_CVAL:
		return true;
	}
	return false;
}

static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
	if (put_user(KVM_REG_ARM_TIMER_CTL, uindices))
		return -EFAULT;
	uindices++;
	if (put_user(KVM_REG_ARM_TIMER_CNT, uindices))
		return -EFAULT;
	uindices++;
	if (put_user(KVM_REG_ARM_TIMER_CVAL, uindices))
		return -EFAULT;

	return 0;
}

static int set_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
	void __user *uaddr = (void __user *)(long)reg->addr;
	u64 val;
	int ret;

	ret = copy_from_user(&val, uaddr, KVM_REG_SIZE(reg->id));
	if (ret != 0)
		return -EFAULT;

	return kvm_arm_timer_set_reg(vcpu, reg->id, val);
}

static int get_timer_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
	void __user *uaddr = (void __user *)(long)reg->addr;
	u64 val;

	val = kvm_arm_timer_get_reg(vcpu, reg->id);
	return copy_to_user(uaddr, &val, KVM_REG_SIZE(reg->id)) ? -EFAULT : 0;
}

/**
 * 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)
{
	unsigned long res = 0;

	res += num_core_regs(vcpu);
	res += kvm_arm_num_sys_reg_descs(vcpu);
	res += kvm_arm_get_fw_num_regs(vcpu);
	res += NUM_TIMER_REGS;

	return res;
}

/**
 * kvm_arm_copy_reg_indices - get indices of all registers.
 *
 * We do core registers right here, then we append system regs.
 */
int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
	int ret;

	ret = copy_core_reg_indices(vcpu, uindices);
	if (ret)
		return ret;
	uindices += ret;

	ret = kvm_arm_copy_fw_reg_indices(vcpu, uindices);
	if (ret)
		return ret;
	uindices += kvm_arm_get_fw_num_regs(vcpu);

	ret = copy_timer_indices(vcpu, uindices);
	if (ret)
		return ret;
	uindices += NUM_TIMER_REGS;

	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;

	switch (reg->id & KVM_REG_ARM_COPROC_MASK) {
	case KVM_REG_ARM_CORE:	return get_core_reg(vcpu, reg);
	case KVM_REG_ARM_FW:	return kvm_arm_get_fw_reg(vcpu, reg);
	case KVM_REG_ARM64_SVE:	return get_sve_reg(vcpu, reg);
	default: break; /* fall through */
	}

	if (is_timer_reg(reg->id))
		return get_timer_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;

	switch (reg->id & KVM_REG_ARM_COPROC_MASK) {
	case KVM_REG_ARM_CORE:	return set_core_reg(vcpu, reg);
	case KVM_REG_ARM_FW:	return kvm_arm_set_fw_reg(vcpu, reg);
	case KVM_REG_ARM64_SVE:	return set_sve_reg(vcpu, reg);
	default: break; /* fall through */
	}

	if (is_timer_reg(reg->id))
		return set_timer_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 __kvm_arm_vcpu_get_events(struct kvm_vcpu *vcpu,
			      struct kvm_vcpu_events *events)
{
	events->exception.serror_pending = !!(vcpu->arch.hcr_el2 & HCR_VSE);
	events->exception.serror_has_esr = cpus_have_const_cap(ARM64_HAS_RAS_EXTN);

	if (events->exception.serror_pending && events->exception.serror_has_esr)
		events->exception.serror_esr = vcpu_get_vsesr(vcpu);

	return 0;
}

int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
			      struct kvm_vcpu_events *events)
{
	bool serror_pending = events->exception.serror_pending;
	bool has_esr = events->exception.serror_has_esr;

	if (serror_pending && has_esr) {
		if (!cpus_have_const_cap(ARM64_HAS_RAS_EXTN))
			return -EINVAL;

		if (!((events->exception.serror_esr) & ~ESR_ELx_ISS_MASK))
			kvm_set_sei_esr(vcpu, events->exception.serror_esr);
		else
			return -EINVAL;
	} else if (serror_pending) {
		kvm_inject_vabt(vcpu);
	}

	return 0;
}

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_A53:
			return KVM_ARM_TARGET_CORTEX_A53;
		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 a default generic target */
	return KVM_ARM_TARGET_GENERIC_V8;
}

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;
}

#define KVM_GUESTDBG_VALID_MASK (KVM_GUESTDBG_ENABLE |    \
			    KVM_GUESTDBG_USE_SW_BP | \
			    KVM_GUESTDBG_USE_HW | \
			    KVM_GUESTDBG_SINGLESTEP)

/**
 * kvm_arch_vcpu_ioctl_set_guest_debug - set up guest debugging
 * @kvm:	pointer to the KVM struct
 * @kvm_guest_debug: the ioctl data buffer
 *
 * This sets up and enables the VM for guest debugging. Userspace
 * passes in a control flag to enable different debug types and
 * potentially other architecture specific information in the rest of
 * the structure.
 */
int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
					struct kvm_guest_debug *dbg)
{
	int ret = 0;

	trace_kvm_set_guest_debug(vcpu, dbg->control);

	if (dbg->control & ~KVM_GUESTDBG_VALID_MASK) {
		ret = -EINVAL;
		goto out;
	}

	if (dbg->control & KVM_GUESTDBG_ENABLE) {
		vcpu->guest_debug = dbg->control;

		/* Hardware assisted Break and Watch points */
		if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW) {
			vcpu->arch.external_debug_state = dbg->arch;
		}

	} else {
		/* If not enabled clear all flags */
		vcpu->guest_debug = 0;
	}

out:
	return ret;
}

int kvm_arm_vcpu_arch_set_attr(struct kvm_vcpu *vcpu,
			       struct kvm_device_attr *attr)
{
	int ret;

	switch (attr->group) {
	case KVM_ARM_VCPU_PMU_V3_CTRL:
		ret = kvm_arm_pmu_v3_set_attr(vcpu, attr);
		break;
	case KVM_ARM_VCPU_TIMER_CTRL:
		ret = kvm_arm_timer_set_attr(vcpu, attr);
		break;
	default:
		ret = -ENXIO;
		break;
	}

	return ret;
}

int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu,
			       struct kvm_device_attr *attr)
{
	int ret;

	switch (attr->group) {
	case KVM_ARM_VCPU_PMU_V3_CTRL:
		ret = kvm_arm_pmu_v3_get_attr(vcpu, attr);
		break;
	case KVM_ARM_VCPU_TIMER_CTRL:
		ret = kvm_arm_timer_get_attr(vcpu, attr);
		break;
	default:
		ret = -ENXIO;
		break;
	}

	return ret;
}

int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
			       struct kvm_device_attr *attr)
{
	int ret;

	switch (attr->group) {
	case KVM_ARM_VCPU_PMU_V3_CTRL:
		ret = kvm_arm_pmu_v3_has_attr(vcpu, attr);
		break;
	case KVM_ARM_VCPU_TIMER_CTRL:
		ret = kvm_arm_timer_has_attr(vcpu, attr);
		break;
	default:
		ret = -ENXIO;
		break;
	}

	return ret;
}