diff options
Diffstat (limited to 'arch/riscv/kvm/vcpu_timer.c')
| -rw-r--r-- | arch/riscv/kvm/vcpu_timer.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c new file mode 100644 index 000000000000..75486b25ac45 --- /dev/null +++ b/arch/riscv/kvm/vcpu_timer.c @@ -0,0 +1,363 @@ +// 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/csr.h> +#include <asm/delay.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) + csr_write(CSR_VSTIMECMP, ncycles & 0xFFFFFFFF); + csr_write(CSR_VSTIMECMPH, ncycles >> 32); +#else + csr_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; + + if (!t->init_done) + return -EINVAL; + + kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_VS_TIMER); + + delta_ns = kvm_riscv_delta_cycles2ns(ncycles, gt, t); + t->next_cycles = ncycles; + hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL); + t->next_set = true; + + return 0; +} + +int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + return t->timer_next_event(vcpu, ncycles); +} + +static enum hrtimer_restart kvm_riscv_vcpu_vstimer_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_vcpu_kick(vcpu); + + return HRTIMER_NORESTART; +} + +bool kvm_riscv_vcpu_timer_pending(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + + if (!kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t) || + kvm_riscv_vcpu_has_interrupts(vcpu, 1UL << IRQ_VS_TIMER)) + return true; + else + return false; +} + +static void kvm_riscv_vcpu_timer_blocking(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + u64 delta_ns; + + if (!t->init_done) + return; + + delta_ns = kvm_riscv_delta_cycles2ns(t->next_cycles, gt, t); + hrtimer_start(&t->hrt, ktime_set(0, delta_ns), HRTIMER_MODE_REL); + t->next_set = true; +} + +static void kvm_riscv_vcpu_timer_unblocking(struct kvm_vcpu *vcpu) +{ + kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer); +} + +int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr; + unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK | + KVM_REG_SIZE_MASK | + KVM_REG_RISCV_TIMER); + u64 reg_val; + + if (KVM_REG_SIZE(reg->id) != sizeof(u64)) + return -EINVAL; + if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64)) + return -ENOENT; + + switch (reg_num) { + case KVM_REG_RISCV_TIMER_REG(frequency): + reg_val = riscv_timebase; + break; + case KVM_REG_RISCV_TIMER_REG(time): + reg_val = kvm_riscv_current_cycles(gt); + break; + case KVM_REG_RISCV_TIMER_REG(compare): + reg_val = t->next_cycles; + break; + case KVM_REG_RISCV_TIMER_REG(state): + reg_val = (t->next_set) ? KVM_RISCV_TIMER_STATE_ON : + KVM_RISCV_TIMER_STATE_OFF; + break; + default: + return -ENOENT; + } + + if (copy_to_user(uaddr, ®_val, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + return 0; +} + +int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + u64 __user *uaddr = (u64 __user *)(unsigned long)reg->addr; + unsigned long reg_num = reg->id & ~(KVM_REG_ARCH_MASK | + KVM_REG_SIZE_MASK | + KVM_REG_RISCV_TIMER); + u64 reg_val; + int ret = 0; + + if (KVM_REG_SIZE(reg->id) != sizeof(u64)) + return -EINVAL; + if (reg_num >= sizeof(struct kvm_riscv_timer) / sizeof(u64)) + return -ENOENT; + + if (copy_from_user(®_val, uaddr, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + switch (reg_num) { + case KVM_REG_RISCV_TIMER_REG(frequency): + if (reg_val != riscv_timebase) + return -EINVAL; + break; + case KVM_REG_RISCV_TIMER_REG(time): + gt->time_delta = reg_val - get_cycles64(); + break; + case KVM_REG_RISCV_TIMER_REG(compare): + t->next_cycles = reg_val; + break; + case KVM_REG_RISCV_TIMER_REG(state): + if (reg_val == KVM_RISCV_TIMER_STATE_ON) + ret = kvm_riscv_vcpu_timer_next_event(vcpu, reg_val); + else + ret = kvm_riscv_vcpu_timer_cancel(t); + break; + default: + ret = -ENOENT; + break; + } + + return ret; +} + +int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + if (t->init_done) + return -EINVAL; + + hrtimer_init(&t->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + t->init_done = true; + t->next_set = false; + + /* Enable sstc for every vcpu if available in hardware */ + if (riscv_isa_extension_available(NULL, SSTC)) { + t->sstc_enabled = true; + t->hrt.function = kvm_riscv_vcpu_vstimer_expired; + t->timer_next_event = kvm_riscv_vcpu_update_vstimecmp; + } else { + t->sstc_enabled = false; + t->hrt.function = kvm_riscv_vcpu_hrtimer_expired; + t->timer_next_event = kvm_riscv_vcpu_update_hrtimer; + } + + return 0; +} + +int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu) +{ + int ret; + + ret = kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer); + vcpu->arch.timer.init_done = false; + + return ret; +} + +int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + t->next_cycles = -1ULL; + return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer); +} + +static void kvm_riscv_vcpu_update_timedelta(struct kvm_vcpu *vcpu) +{ + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + +#if defined(CONFIG_32BIT) + csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta)); + csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32)); +#else + csr_write(CSR_HTIMEDELTA, gt->time_delta); +#endif +} + +void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + kvm_riscv_vcpu_update_timedelta(vcpu); + + if (!t->sstc_enabled) + return; + +#if defined(CONFIG_32BIT) + csr_write(CSR_VSTIMECMP, (u32)t->next_cycles); + csr_write(CSR_VSTIMECMPH, (u32)(t->next_cycles >> 32)); +#else + csr_write(CSR_VSTIMECMP, t->next_cycles); +#endif + + /* timer should be enabled for the remaining operations */ + if (unlikely(!t->init_done)) + return; + + kvm_riscv_vcpu_timer_unblocking(vcpu); +} + +void kvm_riscv_vcpu_timer_sync(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + if (!t->sstc_enabled) + return; + +#if defined(CONFIG_32BIT) + t->next_cycles = csr_read(CSR_VSTIMECMP); + t->next_cycles |= (u64)csr_read(CSR_VSTIMECMPH) << 32; +#else + t->next_cycles = csr_read(CSR_VSTIMECMP); +#endif +} + +void kvm_riscv_vcpu_timer_save(struct kvm_vcpu *vcpu) +{ + struct kvm_vcpu_timer *t = &vcpu->arch.timer; + + if (!t->sstc_enabled) + return; + + /* + * The vstimecmp CSRs are saved by kvm_riscv_vcpu_timer_sync() + * upon every VM exit so no need to save here. + */ + + /* timer should be enabled for the remaining operations */ + if (unlikely(!t->init_done)) + return; + + if (kvm_vcpu_is_blocking(vcpu)) + kvm_riscv_vcpu_timer_blocking(vcpu); +} + +void kvm_riscv_guest_timer_init(struct kvm *kvm) +{ + struct kvm_guest_timer *gt = &kvm->arch.timer; + + riscv_cs_get_mult_shift(>->nsec_mult, >->nsec_shift); + gt->time_delta = -get_cycles64(); +} |