arch/riscv/kvm/vcpu_timer.c

Source file repositories/reference/linux-study-clean/arch/riscv/kvm/vcpu_timer.c

File Facts

System
Linux kernel
Corpus path
arch/riscv/kvm/vcpu_timer.c
Extension
.c
Size
9842 bytes
Lines
384
Domain
Architecture Layer
Bucket
arch/riscv
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
 *
 * Authors:
 *     Atish Patra <atish.patra@wdc.com>
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <clocksource/timer-riscv.h>
#include <asm/delay.h>
#include <asm/kvm_isa.h>
#include <asm/kvm_nacl.h>
#include <asm/kvm_vcpu_timer.h>

static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt)
{
	return get_cycles64() + gt->time_delta;
}

static u64 kvm_riscv_delta_cycles2ns(u64 cycles,
				     struct kvm_guest_timer *gt,
				     struct kvm_vcpu_timer *t)
{
	unsigned long flags;
	u64 cycles_now, cycles_delta, delta_ns;

	local_irq_save(flags);
	cycles_now = kvm_riscv_current_cycles(gt);
	if (cycles_now < cycles)
		cycles_delta = cycles - cycles_now;
	else
		cycles_delta = 0;
	delta_ns = (cycles_delta * gt->nsec_mult) >> gt->nsec_shift;
	local_irq_restore(flags);

	return delta_ns;
}

static enum hrtimer_restart kvm_riscv_vcpu_hrtimer_expired(struct hrtimer *h)
{
	u64 delta_ns;
	struct kvm_vcpu_timer *t = container_of(h, struct kvm_vcpu_timer, hrt);
	struct kvm_vcpu *vcpu = container_of(t, struct kvm_vcpu, arch.timer);
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;

	if (kvm_riscv_current_cycles(gt) < t->next_cycles) {
		delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t);
		hrtimer_forward_now(&t->hrt, ktime_set(0, delta_ns));
		return HRTIMER_RESTART;
	}

	t->next_set = false;
	kvm_riscv_vcpu_set_interrupt(vcpu, IRQ_VS_TIMER);

	return HRTIMER_NORESTART;
}

static int kvm_riscv_vcpu_timer_cancel(struct kvm_vcpu_timer *t)
{
	if (!t->init_done || !t->next_set)
		return -EINVAL;

	hrtimer_cancel(&t->hrt);
	t->next_set = false;

	return 0;
}

static int kvm_riscv_vcpu_update_vstimecmp(struct kvm_vcpu *vcpu, u64 ncycles)
{
#if defined(CONFIG_32BIT)
	ncsr_write(CSR_VSTIMECMP,  ULONG_MAX);
	ncsr_write(CSR_VSTIMECMPH, ncycles >> 32);
	ncsr_write(CSR_VSTIMECMP, (u32)ncycles);
#else
	ncsr_write(CSR_VSTIMECMP, ncycles);
#endif
	return 0;
}

static int kvm_riscv_vcpu_update_hrtimer(struct kvm_vcpu *vcpu, u64 ncycles)
{
	struct kvm_vcpu_timer *t = &vcpu->arch.timer;
	struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer;
	u64 delta_ns;

Annotation

Implementation Notes