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-rw-r--r--arch/riscv/kvm/vcpu_timer.c363
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 0000000000..75486b25ac
--- /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, &reg_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(&reg_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(&gt->nsec_mult, &gt->nsec_shift);
+ gt->time_delta = -get_cycles64();
+}