xref: /linux/arch/riscv/kvm/vcpu.c (revision 9e4e86a604dfd06402933467578c4b79f5412b2c)

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *     Anup Patel <anup.patel@wdc.com>
 */

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/vmalloc.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/kvm_host.h>
#include <asm/cacheflush.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_nacl.h>
#include <asm/kvm_vcpu_vector.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

static DEFINE_PER_CPU(struct kvm_vcpu *, kvm_former_vcpu);

const struct kvm_stats_desc kvm_vcpu_stats_desc[] = {
	KVM_GENERIC_VCPU_STATS(),
	STATS_DESC_COUNTER(VCPU, ecall_exit_stat),
	STATS_DESC_COUNTER(VCPU, wfi_exit_stat),
	STATS_DESC_COUNTER(VCPU, wrs_exit_stat),
	STATS_DESC_COUNTER(VCPU, mmio_exit_user),
	STATS_DESC_COUNTER(VCPU, mmio_exit_kernel),
	STATS_DESC_COUNTER(VCPU, csr_exit_user),
	STATS_DESC_COUNTER(VCPU, csr_exit_kernel),
	STATS_DESC_COUNTER(VCPU, signal_exits),
	STATS_DESC_COUNTER(VCPU, exits),
	STATS_DESC_COUNTER(VCPU, instr_illegal_exits),
	STATS_DESC_COUNTER(VCPU, load_misaligned_exits),
	STATS_DESC_COUNTER(VCPU, store_misaligned_exits),
	STATS_DESC_COUNTER(VCPU, load_access_exits),
	STATS_DESC_COUNTER(VCPU, store_access_exits),
};

const struct kvm_stats_header kvm_vcpu_stats_header = {
	.name_size = KVM_STATS_NAME_SIZE,
	.num_desc = ARRAY_SIZE(kvm_vcpu_stats_desc),
	.id_offset = sizeof(struct kvm_stats_header),
	.desc_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE,
	.data_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE +
		       sizeof(kvm_vcpu_stats_desc),
};

static void kvm_riscv_vcpu_context_reset(struct kvm_vcpu *vcpu,
					 bool kvm_sbi_reset)
{
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
	struct kvm_cpu_context *cntx = &vcpu->arch.guest_context;
	void *vector_datap = cntx->vector.datap;

	memset(cntx, 0, sizeof(*cntx));
	memset(csr, 0, sizeof(*csr));
	memset(&vcpu->arch.smstateen_csr, 0, sizeof(vcpu->arch.smstateen_csr));

	/* Restore datap as it's not a part of the guest context. */
	cntx->vector.datap = vector_datap;

	if (kvm_sbi_reset)
		kvm_riscv_vcpu_sbi_load_reset_state(vcpu);

	/* Setup reset state of shadow SSTATUS and HSTATUS CSRs */
	cntx->sstatus = SR_SPP | SR_SPIE;

	cntx->hstatus |= HSTATUS_VTW;
	cntx->hstatus |= HSTATUS_SPVP;
	cntx->hstatus |= HSTATUS_SPV;
}

static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu, bool kvm_sbi_reset)
{
	bool loaded;

	/**
	 * The preemption should be disabled here because it races with
	 * kvm_sched_out/kvm_sched_in(called from preempt notifiers) which
	 * also calls vcpu_load/put.
	 */
	get_cpu();
	loaded = (vcpu->cpu != -1);
	if (loaded)
		kvm_arch_vcpu_put(vcpu);

	vcpu->arch.last_exit_cpu = -1;

	kvm_riscv_vcpu_context_reset(vcpu, kvm_sbi_reset);

	kvm_riscv_vcpu_fp_reset(vcpu);

	kvm_riscv_vcpu_vector_reset(vcpu);

	kvm_riscv_vcpu_timer_reset(vcpu);

	kvm_riscv_vcpu_aia_reset(vcpu);

	bitmap_zero(vcpu->arch.irqs_pending, KVM_RISCV_VCPU_NR_IRQS);
	bitmap_zero(vcpu->arch.irqs_pending_mask, KVM_RISCV_VCPU_NR_IRQS);

	kvm_riscv_vcpu_pmu_reset(vcpu);

	vcpu->arch.hfence_head = 0;
	vcpu->arch.hfence_tail = 0;
	memset(vcpu->arch.hfence_queue, 0, sizeof(vcpu->arch.hfence_queue));

	kvm_riscv_vcpu_sbi_reset(vcpu);

	/* Reset the guest CSRs for hotplug usecase */
	if (loaded)
		kvm_arch_vcpu_load(vcpu, smp_processor_id());
	put_cpu();
}

int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
{
	return 0;
}

int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
{
	int rc;

	spin_lock_init(&vcpu->arch.mp_state_lock);

	/* Mark this VCPU never ran */
	vcpu->arch.ran_atleast_once = false;

	vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
	bitmap_zero(vcpu->arch.isa, RISCV_ISA_EXT_MAX);

	/* Setup VCPU config */
	kvm_riscv_vcpu_config_init(vcpu);

	/* Setup ISA features available to VCPU */
	kvm_riscv_vcpu_setup_isa(vcpu);

	/* Setup vendor, arch, and implementation details */
	vcpu->arch.mvendorid = sbi_get_mvendorid();
	vcpu->arch.marchid = sbi_get_marchid();
	vcpu->arch.mimpid = sbi_get_mimpid();

	/* Setup VCPU hfence queue */
	spin_lock_init(&vcpu->arch.hfence_lock);

	spin_lock_init(&vcpu->arch.reset_state.lock);

	rc = kvm_riscv_vcpu_alloc_vector_context(vcpu);
	if (rc)
		return rc;

	/* Setup VCPU timer */
	kvm_riscv_vcpu_timer_init(vcpu);

	/* setup performance monitoring */
	kvm_riscv_vcpu_pmu_init(vcpu);

	/* Setup VCPU AIA */
	kvm_riscv_vcpu_aia_init(vcpu);

	/*
	 * Setup SBI extensions
	 * NOTE: This must be the last thing to be initialized.
	 */
	kvm_riscv_vcpu_sbi_init(vcpu);

	/* Reset VCPU */
	kvm_riscv_reset_vcpu(vcpu, false);

	return 0;
}

void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
	/**
	 * vcpu with id 0 is the designated boot cpu.
	 * Keep all vcpus with non-zero id in power-off state so that
	 * they can be brought up using SBI HSM extension.
	 */
	if (vcpu->vcpu_idx != 0)
		kvm_riscv_vcpu_power_off(vcpu);
}

void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
{
	kvm_riscv_vcpu_sbi_deinit(vcpu);

	/* Cleanup VCPU AIA context */
	kvm_riscv_vcpu_aia_deinit(vcpu);

	/* Cleanup VCPU timer */
	kvm_riscv_vcpu_timer_deinit(vcpu);

	kvm_riscv_vcpu_pmu_deinit(vcpu);

	/* Free unused pages pre-allocated for G-stage page table mappings */
	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);

	/* Free vector context space for host and guest kernel */
	kvm_riscv_vcpu_free_vector_context(vcpu);
}

int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
	return kvm_riscv_vcpu_timer_pending(vcpu);
}

int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
{
	return (kvm_riscv_vcpu_has_interrupts(vcpu, -1ULL) &&
		!kvm_riscv_vcpu_stopped(vcpu) && !vcpu->arch.pause);
}

int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
{
	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
}

bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
{
	return (vcpu->arch.guest_context.sstatus & SR_SPP) ? true : false;
}

#ifdef CONFIG_GUEST_PERF_EVENTS
unsigned long kvm_arch_vcpu_get_ip(struct kvm_vcpu *vcpu)
{
	return vcpu->arch.guest_context.sepc;
}
#endif

vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
{
	return VM_FAULT_SIGBUS;
}

long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl,
				  unsigned long arg)
{
	struct kvm_vcpu *vcpu = filp->private_data;
	void __user *argp = (void __user *)arg;

	if (ioctl == KVM_INTERRUPT) {
		struct kvm_interrupt irq;

		if (copy_from_user(&irq, argp, sizeof(irq)))
			return -EFAULT;

		if (irq.irq == KVM_INTERRUPT_SET)
			return kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_VS_EXT);
		else
			return kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_EXT);
	}

	return -ENOIOCTLCMD;
}

long kvm_arch_vcpu_ioctl(struct file *filp,
			 unsigned int ioctl, unsigned long arg)
{
	struct kvm_vcpu *vcpu = filp->private_data;
	void __user *argp = (void __user *)arg;
	long r = -EINVAL;

	switch (ioctl) {
	case KVM_SET_ONE_REG:
	case KVM_GET_ONE_REG: {
		struct kvm_one_reg reg;

		r = -EFAULT;
		if (copy_from_user(&reg, argp, sizeof(reg)))
			break;

		if (ioctl == KVM_SET_ONE_REG)
			r = kvm_riscv_vcpu_set_reg(vcpu, &reg);
		else
			r = kvm_riscv_vcpu_get_reg(vcpu, &reg);
		break;
	}
	case KVM_GET_REG_LIST: {
		struct kvm_reg_list __user *user_list = argp;
		struct kvm_reg_list reg_list;
		unsigned int n;

		r = -EFAULT;
		if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
			break;
		n = reg_list.n;
		reg_list.n = kvm_riscv_vcpu_num_regs(vcpu);
		if (copy_to_user(user_list, &reg_list, sizeof(reg_list)))
			break;
		r = -E2BIG;
		if (n < reg_list.n)
			break;
		r = kvm_riscv_vcpu_copy_reg_indices(vcpu, user_list->reg);
		break;
	}
	default:
		break;
	}

	return r;
}

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_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;
}

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;
}

void kvm_riscv_vcpu_flush_interrupts(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;
	unsigned long mask, val;

	if (READ_ONCE(vcpu->arch.irqs_pending_mask[0])) {
		mask = xchg_acquire(&vcpu->arch.irqs_pending_mask[0], 0);
		val = READ_ONCE(vcpu->arch.irqs_pending[0]) & mask;

		csr->hvip &= ~mask;
		csr->hvip |= val;
	}

	/* Flush AIA high interrupts */
	kvm_riscv_vcpu_aia_flush_interrupts(vcpu);
}

void kvm_riscv_vcpu_sync_interrupts(struct kvm_vcpu *vcpu)
{
	unsigned long hvip;
	struct kvm_vcpu_arch *v = &vcpu->arch;
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	/* Read current HVIP and VSIE CSRs */
	csr->vsie = ncsr_read(CSR_VSIE);

	/* Sync-up HVIP.VSSIP bit changes does by Guest */
	hvip = ncsr_read(CSR_HVIP);
	if ((csr->hvip ^ hvip) & (1UL << IRQ_VS_SOFT)) {
		if (hvip & (1UL << IRQ_VS_SOFT)) {
			if (!test_and_set_bit(IRQ_VS_SOFT,
					      v->irqs_pending_mask))
				set_bit(IRQ_VS_SOFT, v->irqs_pending);
		} else {
			if (!test_and_set_bit(IRQ_VS_SOFT,
					      v->irqs_pending_mask))
				clear_bit(IRQ_VS_SOFT, v->irqs_pending);
		}
	}

	/* Sync up the HVIP.LCOFIP bit changes (only clear) by the guest */
	if ((csr->hvip ^ hvip) & (1UL << IRQ_PMU_OVF)) {
		if (!(hvip & (1UL << IRQ_PMU_OVF)) &&
		    !test_and_set_bit(IRQ_PMU_OVF, v->irqs_pending_mask))
			clear_bit(IRQ_PMU_OVF, v->irqs_pending);
	}

	/* Sync-up AIA high interrupts */
	kvm_riscv_vcpu_aia_sync_interrupts(vcpu);

	/* Sync-up timer CSRs */
	kvm_riscv_vcpu_timer_sync(vcpu);
}

int kvm_riscv_vcpu_set_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
{
	/*
	 * We only allow VS-mode software, timer, and external
	 * interrupts when irq is one of the local interrupts
	 * defined by RISC-V privilege specification.
	 */
	if (irq < IRQ_LOCAL_MAX &&
	    irq != IRQ_VS_SOFT &&
	    irq != IRQ_VS_TIMER &&
	    irq != IRQ_VS_EXT &&
	    irq != IRQ_PMU_OVF)
		return -EINVAL;

	set_bit(irq, vcpu->arch.irqs_pending);
	smp_mb__before_atomic();
	set_bit(irq, vcpu->arch.irqs_pending_mask);

	kvm_vcpu_kick(vcpu);

	return 0;
}

int kvm_riscv_vcpu_unset_interrupt(struct kvm_vcpu *vcpu, unsigned int irq)
{
	/*
	 * We only allow VS-mode software, timer, counter overflow and external
	 * interrupts when irq is one of the local interrupts
	 * defined by RISC-V privilege specification.
	 */
	if (irq < IRQ_LOCAL_MAX &&
	    irq != IRQ_VS_SOFT &&
	    irq != IRQ_VS_TIMER &&
	    irq != IRQ_VS_EXT &&
	    irq != IRQ_PMU_OVF)
		return -EINVAL;

	clear_bit(irq, vcpu->arch.irqs_pending);
	smp_mb__before_atomic();
	set_bit(irq, vcpu->arch.irqs_pending_mask);

	return 0;
}

bool kvm_riscv_vcpu_has_interrupts(struct kvm_vcpu *vcpu, u64 mask)
{
	unsigned long ie;

	ie = ((vcpu->arch.guest_csr.vsie & VSIP_VALID_MASK)
		<< VSIP_TO_HVIP_SHIFT) & (unsigned long)mask;
	ie |= vcpu->arch.guest_csr.vsie & ~IRQ_LOCAL_MASK &
		(unsigned long)mask;
	if (READ_ONCE(vcpu->arch.irqs_pending[0]) & ie)
		return true;

	/* Check AIA high interrupts */
	return kvm_riscv_vcpu_aia_has_interrupts(vcpu, mask);
}

void __kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu)
{
	WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_STOPPED);
	kvm_make_request(KVM_REQ_SLEEP, vcpu);
	kvm_vcpu_kick(vcpu);
}

void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu)
{
	spin_lock(&vcpu->arch.mp_state_lock);
	__kvm_riscv_vcpu_power_off(vcpu);
	spin_unlock(&vcpu->arch.mp_state_lock);
}

void __kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu)
{
	WRITE_ONCE(vcpu->arch.mp_state.mp_state, KVM_MP_STATE_RUNNABLE);
	kvm_vcpu_wake_up(vcpu);
}

void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu)
{
	spin_lock(&vcpu->arch.mp_state_lock);
	__kvm_riscv_vcpu_power_on(vcpu);
	spin_unlock(&vcpu->arch.mp_state_lock);
}

bool kvm_riscv_vcpu_stopped(struct kvm_vcpu *vcpu)
{
	return READ_ONCE(vcpu->arch.mp_state.mp_state) == KVM_MP_STATE_STOPPED;
}

int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
				    struct kvm_mp_state *mp_state)
{
	*mp_state = READ_ONCE(vcpu->arch.mp_state);

	return 0;
}

int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
				    struct kvm_mp_state *mp_state)
{
	int ret = 0;

	spin_lock(&vcpu->arch.mp_state_lock);

	switch (mp_state->mp_state) {
	case KVM_MP_STATE_RUNNABLE:
		WRITE_ONCE(vcpu->arch.mp_state, *mp_state);
		break;
	case KVM_MP_STATE_STOPPED:
		__kvm_riscv_vcpu_power_off(vcpu);
		break;
	case KVM_MP_STATE_INIT_RECEIVED:
		if (vcpu->kvm->arch.mp_state_reset)
			kvm_riscv_reset_vcpu(vcpu, false);
		else
			ret = -EINVAL;
		break;
	default:
		ret = -EINVAL;
	}

	spin_unlock(&vcpu->arch.mp_state_lock);

	return ret;
}

int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
					struct kvm_guest_debug *dbg)
{
	if (dbg->control & KVM_GUESTDBG_ENABLE)
		vcpu->guest_debug = dbg->control;
	else
		vcpu->guest_debug = 0;

	return 0;
}

void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
{
	void *nsh;
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	/*
	 * If VCPU is being reloaded on the same physical CPU and no
	 * other KVM VCPU has run on this CPU since it was last put,
	 * we can skip the expensive CSR and HGATP writes.
	 *
	 * Note: If a new CSR is added to this fast-path skip block,
	 * make sure that 'csr_dirty' is set to true in any
	 * ioctl (e.g., KVM_SET_ONE_REG) that modifies it.
	 */
	if (vcpu != __this_cpu_read(kvm_former_vcpu))
		__this_cpu_write(kvm_former_vcpu, vcpu);
	else if (vcpu->arch.last_exit_cpu == cpu && !vcpu->arch.csr_dirty)
		goto csr_restore_done;

	vcpu->arch.csr_dirty = false;

	/*
	 * Load VCPU config CSRs before other CSRs because
	 * the read/write behaviour of certain CSRs change
	 * based on VCPU config CSRs.
	 */
	kvm_riscv_vcpu_config_load(vcpu);

	if (kvm_riscv_nacl_sync_csr_available()) {
		nsh = nacl_shmem();
		nacl_csr_write(nsh, CSR_VSSTATUS, csr->vsstatus);
		nacl_csr_write(nsh, CSR_VSIE, csr->vsie);
		nacl_csr_write(nsh, CSR_VSTVEC, csr->vstvec);
		nacl_csr_write(nsh, CSR_VSSCRATCH, csr->vsscratch);
		nacl_csr_write(nsh, CSR_VSEPC, csr->vsepc);
		nacl_csr_write(nsh, CSR_VSCAUSE, csr->vscause);
		nacl_csr_write(nsh, CSR_VSTVAL, csr->vstval);
		nacl_csr_write(nsh, CSR_HVIP, csr->hvip);
		nacl_csr_write(nsh, CSR_VSATP, csr->vsatp);
	} else {
		csr_write(CSR_VSSTATUS, csr->vsstatus);
		csr_write(CSR_VSIE, csr->vsie);
		csr_write(CSR_VSTVEC, csr->vstvec);
		csr_write(CSR_VSSCRATCH, csr->vsscratch);
		csr_write(CSR_VSEPC, csr->vsepc);
		csr_write(CSR_VSCAUSE, csr->vscause);
		csr_write(CSR_VSTVAL, csr->vstval);
		csr_write(CSR_HVIP, csr->hvip);
		csr_write(CSR_VSATP, csr->vsatp);
	}

	kvm_riscv_mmu_update_hgatp(vcpu);

	kvm_riscv_vcpu_aia_load(vcpu, cpu);

csr_restore_done:
	kvm_riscv_vcpu_timer_restore(vcpu);

	kvm_riscv_vcpu_host_fp_save(&vcpu->arch.host_context);
	kvm_riscv_vcpu_guest_fp_restore(&vcpu->arch.guest_context,
					vcpu->arch.isa);
	kvm_riscv_vcpu_host_vector_save(&vcpu->arch.host_context);
	kvm_riscv_vcpu_guest_vector_restore(&vcpu->arch.guest_context,
					    vcpu->arch.isa);

	kvm_make_request(KVM_REQ_STEAL_UPDATE, vcpu);

	vcpu->cpu = cpu;
}

void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
{
	void *nsh;
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	vcpu->cpu = -1;

	kvm_riscv_vcpu_aia_put(vcpu);

	kvm_riscv_vcpu_guest_fp_save(&vcpu->arch.guest_context,
				     vcpu->arch.isa);
	kvm_riscv_vcpu_host_fp_restore(&vcpu->arch.host_context);

	kvm_riscv_vcpu_timer_save(vcpu);
	kvm_riscv_vcpu_guest_vector_save(&vcpu->arch.guest_context,
					 vcpu->arch.isa);
	kvm_riscv_vcpu_host_vector_restore(&vcpu->arch.host_context);

	if (kvm_riscv_nacl_available()) {
		nsh = nacl_shmem();
		csr->vsstatus = nacl_csr_read(nsh, CSR_VSSTATUS);
		csr->vsie = nacl_csr_read(nsh, CSR_VSIE);
		csr->vstvec = nacl_csr_read(nsh, CSR_VSTVEC);
		csr->vsscratch = nacl_csr_read(nsh, CSR_VSSCRATCH);
		csr->vsepc = nacl_csr_read(nsh, CSR_VSEPC);
		csr->vscause = nacl_csr_read(nsh, CSR_VSCAUSE);
		csr->vstval = nacl_csr_read(nsh, CSR_VSTVAL);
		csr->hvip = nacl_csr_read(nsh, CSR_HVIP);
		csr->vsatp = nacl_csr_read(nsh, CSR_VSATP);
	} else {
		csr->vsstatus = csr_read(CSR_VSSTATUS);
		csr->vsie = csr_read(CSR_VSIE);
		csr->vstvec = csr_read(CSR_VSTVEC);
		csr->vsscratch = csr_read(CSR_VSSCRATCH);
		csr->vsepc = csr_read(CSR_VSEPC);
		csr->vscause = csr_read(CSR_VSCAUSE);
		csr->vstval = csr_read(CSR_VSTVAL);
		csr->hvip = csr_read(CSR_HVIP);
		csr->vsatp = csr_read(CSR_VSATP);
	}
}

/**
 * kvm_riscv_check_vcpu_requests - check and handle pending vCPU requests
 * @vcpu:	the VCPU pointer
 *
 * Return: 1 if we should enter the guest
 *	    0 if we should exit to userspace
 */
static int kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
{
	struct rcuwait *wait = kvm_arch_vcpu_get_wait(vcpu);

	if (kvm_request_pending(vcpu)) {
		if (kvm_check_request(KVM_REQ_SLEEP, vcpu)) {
			kvm_vcpu_srcu_read_unlock(vcpu);
			rcuwait_wait_event(wait,
				(!kvm_riscv_vcpu_stopped(vcpu)) && (!vcpu->arch.pause),
				TASK_INTERRUPTIBLE);
			kvm_vcpu_srcu_read_lock(vcpu);

			if (kvm_riscv_vcpu_stopped(vcpu) || vcpu->arch.pause) {
				/*
				 * Awaken to handle a signal, request to
				 * sleep again later.
				 */
				kvm_make_request(KVM_REQ_SLEEP, vcpu);
			}
		}

		if (kvm_check_request(KVM_REQ_VCPU_RESET, vcpu))
			kvm_riscv_reset_vcpu(vcpu, true);

		if (kvm_check_request(KVM_REQ_UPDATE_HGATP, vcpu))
			kvm_riscv_mmu_update_hgatp(vcpu);

		if (kvm_check_request(KVM_REQ_FENCE_I, vcpu))
			kvm_riscv_fence_i_process(vcpu);

		if (kvm_check_request(KVM_REQ_TLB_FLUSH, vcpu))
			kvm_riscv_tlb_flush_process(vcpu);

		if (kvm_check_request(KVM_REQ_HFENCE_VVMA_ALL, vcpu))
			kvm_riscv_hfence_vvma_all_process(vcpu);

		if (kvm_check_request(KVM_REQ_HFENCE, vcpu))
			kvm_riscv_hfence_process(vcpu);

		if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
			kvm_riscv_vcpu_record_steal_time(vcpu);

		if (kvm_dirty_ring_check_request(vcpu))
			return 0;
	}

	return 1;
}

static void kvm_riscv_update_hvip(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	ncsr_write(CSR_HVIP, csr->hvip);
	kvm_riscv_vcpu_aia_update_hvip(vcpu);
}

static __always_inline void kvm_riscv_vcpu_swap_in_guest_state(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_smstateen_csr *smcsr = &vcpu->arch.smstateen_csr;
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	vcpu->arch.host_scounteren = csr_swap(CSR_SCOUNTEREN, csr->scounteren);
	vcpu->arch.host_senvcfg = csr_swap(CSR_SENVCFG, csr->senvcfg);
	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN))
		vcpu->arch.host_sstateen0 = csr_swap(CSR_SSTATEEN0, smcsr->sstateen0);
}

static __always_inline void kvm_riscv_vcpu_swap_in_host_state(struct kvm_vcpu *vcpu)
{
	struct kvm_vcpu_smstateen_csr *smcsr = &vcpu->arch.smstateen_csr;
	struct kvm_vcpu_csr *csr = &vcpu->arch.guest_csr;

	csr->scounteren = csr_swap(CSR_SCOUNTEREN, vcpu->arch.host_scounteren);
	csr->senvcfg = csr_swap(CSR_SENVCFG, vcpu->arch.host_senvcfg);
	if (riscv_has_extension_unlikely(RISCV_ISA_EXT_SMSTATEEN))
		smcsr->sstateen0 = csr_swap(CSR_SSTATEEN0, vcpu->arch.host_sstateen0);
}

/*
 * Actually run the vCPU, entering an RCU extended quiescent state (EQS) while
 * the vCPU is running.
 *
 * This must be noinstr as instrumentation may make use of RCU, and this is not
 * safe during the EQS.
 */
static void noinstr kvm_riscv_vcpu_enter_exit(struct kvm_vcpu *vcpu,
					      struct kvm_cpu_trap *trap)
{
	void *nsh;
	struct kvm_cpu_context *gcntx = &vcpu->arch.guest_context;
	struct kvm_cpu_context *hcntx = &vcpu->arch.host_context;

	/*
	 * We save trap CSRs (such as SEPC, SCAUSE, STVAL, HTVAL, and
	 * HTINST) here because we do local_irq_enable() after this
	 * function in kvm_arch_vcpu_ioctl_run() which can result in
	 * an interrupt immediately after local_irq_enable() and can
	 * potentially change trap CSRs.
	 */

	kvm_riscv_vcpu_swap_in_guest_state(vcpu);
	guest_state_enter_irqoff();

	if (kvm_riscv_nacl_sync_sret_available()) {
		nsh = nacl_shmem();

		if (kvm_riscv_nacl_autoswap_csr_available()) {
			hcntx->hstatus =
				nacl_csr_read(nsh, CSR_HSTATUS);
			nacl_scratch_write_long(nsh,
						SBI_NACL_SHMEM_AUTOSWAP_OFFSET +
						SBI_NACL_SHMEM_AUTOSWAP_HSTATUS,
						gcntx->hstatus);
			nacl_scratch_write_long(nsh,
						SBI_NACL_SHMEM_AUTOSWAP_OFFSET,
						SBI_NACL_SHMEM_AUTOSWAP_FLAG_HSTATUS);
		} else if (kvm_riscv_nacl_sync_csr_available()) {
			hcntx->hstatus = nacl_csr_swap(nsh,
						       CSR_HSTATUS, gcntx->hstatus);
		} else {
			hcntx->hstatus = csr_swap(CSR_HSTATUS, gcntx->hstatus);
		}

		nacl_scratch_write_longs(nsh,
					 SBI_NACL_SHMEM_SRET_OFFSET +
					 SBI_NACL_SHMEM_SRET_X(1),
					 &gcntx->ra,
					 SBI_NACL_SHMEM_SRET_X_LAST);

		__kvm_riscv_nacl_switch_to(&vcpu->arch, SBI_EXT_NACL,
					   SBI_EXT_NACL_SYNC_SRET);

		if (kvm_riscv_nacl_autoswap_csr_available()) {
			nacl_scratch_write_long(nsh,
						SBI_NACL_SHMEM_AUTOSWAP_OFFSET,
						0);
			gcntx->hstatus = nacl_scratch_read_long(nsh,
								SBI_NACL_SHMEM_AUTOSWAP_OFFSET +
								SBI_NACL_SHMEM_AUTOSWAP_HSTATUS);
		} else {
			gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus);
		}

		trap->htval = nacl_csr_read(nsh, CSR_HTVAL);
		trap->htinst = nacl_csr_read(nsh, CSR_HTINST);
	} else {
		hcntx->hstatus = csr_swap(CSR_HSTATUS, gcntx->hstatus);

		__kvm_riscv_switch_to(&vcpu->arch);

		gcntx->hstatus = csr_swap(CSR_HSTATUS, hcntx->hstatus);

		trap->htval = csr_read(CSR_HTVAL);
		trap->htinst = csr_read(CSR_HTINST);
	}

	trap->sepc = gcntx->sepc;
	trap->scause = csr_read(CSR_SCAUSE);
	trap->stval = csr_read(CSR_STVAL);

	vcpu->arch.last_exit_cpu = vcpu->cpu;
	guest_state_exit_irqoff();
	kvm_riscv_vcpu_swap_in_host_state(vcpu);
}

int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
{
	int ret;
	struct kvm_cpu_trap trap;
	struct kvm_run *run = vcpu->run;

	if (!vcpu->arch.ran_atleast_once)
		kvm_riscv_vcpu_config_ran_once(vcpu);

	/* Mark this VCPU ran at least once */
	vcpu->arch.ran_atleast_once = true;

	kvm_vcpu_srcu_read_lock(vcpu);

	switch (run->exit_reason) {
	case KVM_EXIT_MMIO:
		/* Process MMIO value returned from user-space */
		ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run);
		break;
	case KVM_EXIT_RISCV_SBI:
		/* Process SBI value returned from user-space */
		ret = kvm_riscv_vcpu_sbi_return(vcpu, vcpu->run);
		break;
	case KVM_EXIT_RISCV_CSR:
		/* Process CSR value returned from user-space */
		ret = kvm_riscv_vcpu_csr_return(vcpu, vcpu->run);
		break;
	default:
		ret = 0;
		break;
	}
	if (ret) {
		kvm_vcpu_srcu_read_unlock(vcpu);
		return ret;
	}

	if (!vcpu->wants_to_run) {
		kvm_vcpu_srcu_read_unlock(vcpu);
		return -EINTR;
	}

	vcpu_load(vcpu);

	kvm_sigset_activate(vcpu);

	ret = 1;
	run->exit_reason = KVM_EXIT_UNKNOWN;
	while (ret > 0) {
		/* Check conditions before entering the guest */
		ret = kvm_xfer_to_guest_mode_handle_work(vcpu);
		if (ret)
			continue;
		ret = 1;

		kvm_riscv_gstage_vmid_update(vcpu);

		ret = kvm_riscv_check_vcpu_requests(vcpu);
		if (ret <= 0)
			continue;

		preempt_disable();

		/* Update AIA HW state before entering guest */
		ret = kvm_riscv_vcpu_aia_update(vcpu);
		if (ret <= 0) {
			preempt_enable();
			continue;
		}

		local_irq_disable();

		/*
		 * Ensure we set mode to IN_GUEST_MODE after we disable
		 * interrupts and before the final VCPU requests check.
		 * See the comment in kvm_vcpu_exiting_guest_mode() and
		 * Documentation/virt/kvm/vcpu-requests.rst
		 */
		vcpu->mode = IN_GUEST_MODE;

		kvm_vcpu_srcu_read_unlock(vcpu);
		smp_mb__after_srcu_read_unlock();

		/*
		 * We might have got VCPU interrupts updated asynchronously
		 * so update it in HW.
		 */
		kvm_riscv_vcpu_flush_interrupts(vcpu);

		/* Update HVIP CSR for current CPU */
		kvm_riscv_update_hvip(vcpu);

		if (kvm_riscv_gstage_vmid_ver_changed(&vcpu->kvm->arch.vmid) ||
		    kvm_request_pending(vcpu) ||
		    xfer_to_guest_mode_work_pending()) {
			vcpu->mode = OUTSIDE_GUEST_MODE;
			local_irq_enable();
			preempt_enable();
			kvm_vcpu_srcu_read_lock(vcpu);
			continue;
		}

		/*
		 * Sanitize VMID mappings cached (TLB) on current CPU
		 *
		 * Note: This should be done after G-stage VMID has been
		 * updated using kvm_riscv_gstage_vmid_ver_changed()
		 */
		kvm_riscv_local_tlb_sanitize(vcpu);

		trace_kvm_entry(vcpu);

		guest_timing_enter_irqoff();

		kvm_riscv_vcpu_enter_exit(vcpu, &trap);

		vcpu->mode = OUTSIDE_GUEST_MODE;
		vcpu->stat.exits++;

		/* Syncup interrupts state with HW */
		kvm_riscv_vcpu_sync_interrupts(vcpu);

		/*
		 * We must ensure that any pending interrupts are taken before
		 * we exit guest timing so that timer ticks are accounted as
		 * guest time. Transiently unmask interrupts so that any
		 * pending interrupts are taken.
		 *
		 * There's no barrier which ensures that pending interrupts are
		 * recognised, so we just hope that the CPU takes any pending
		 * interrupts between the enable and disable.
		 */
		local_irq_enable();
		local_irq_disable();

		guest_timing_exit_irqoff();

		local_irq_enable();

		trace_kvm_exit(&trap);

		preempt_enable();

		kvm_vcpu_srcu_read_lock(vcpu);

		ret = kvm_riscv_vcpu_exit(vcpu, run, &trap);
	}

	kvm_sigset_deactivate(vcpu);

	vcpu_put(vcpu);

	kvm_vcpu_srcu_read_unlock(vcpu);

	return ret;
}