From: Atish Patra atish.patra@wdc.com
euleros inclusion category: feature feature: initial KVM RISC-V support bugzilla: 46845 CVE: NA
The RISC-V hypervisor specification doesn't have any virtual timer feature.
Due to this, the guest VCPU timer will be programmed via SBI calls. The host will use a separate hrtimer event for each guest VCPU to provide timer functionality. We inject a virtual timer interrupt to the guest VCPU whenever the guest VCPU hrtimer event expires.
This patch adds guest VCPU timer implementation along with ONE_REG interface to access VCPU timer state from user space.
Reference: https://gitee.com/openeuler/kernel/issues/I26X9V Signed-off-by: Atish Patra atish.patra@wdc.com Signed-off-by: Anup Patel anup.patel@wdc.com Acked-by: Paolo Bonzini pbonzini@redhat.com Reviewed-by: Paolo Bonzini pbonzini@redhat.com Acked-by: Daniel Lezcano daniel.lezcano@linaro.org --- arch/riscv/include/asm/kvm_host.h | 7 + arch/riscv/include/asm/kvm_vcpu_timer.h | 44 +++++ arch/riscv/include/uapi/asm/kvm.h | 17 ++ arch/riscv/kvm/Makefile | 2 +- arch/riscv/kvm/vcpu.c | 14 ++ arch/riscv/kvm/vcpu_timer.c | 225 ++++++++++++++++++++++++ arch/riscv/kvm/vm.c | 2 +- drivers/clocksource/timer-riscv.c | 8 + include/clocksource/timer-riscv.h | 16 ++ 9 files changed, 333 insertions(+), 2 deletions(-) create mode 100644 arch/riscv/include/asm/kvm_vcpu_timer.h create mode 100644 arch/riscv/kvm/vcpu_timer.c create mode 100644 include/clocksource/timer-riscv.h
diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 64311b262..4daffc93f 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -12,6 +12,7 @@ #include <linux/types.h> #include <linux/kvm.h> #include <linux/kvm_types.h> +#include <asm/kvm_vcpu_timer.h>
#ifdef CONFIG_64BIT #define KVM_MAX_VCPUS (1U << 16) @@ -66,6 +67,9 @@ struct kvm_arch { /* stage2 page table */ pgd_t *pgd; phys_addr_t pgd_phys; + + /* Guest Timer */ + struct kvm_guest_timer timer; };
struct kvm_mmio_decode { @@ -181,6 +185,9 @@ struct kvm_vcpu_arch { unsigned long irqs_pending; unsigned long irqs_pending_mask;
+ /* VCPU Timer */ + struct kvm_vcpu_timer timer; + /* MMIO instruction details */ struct kvm_mmio_decode mmio_decode;
diff --git a/arch/riscv/include/asm/kvm_vcpu_timer.h b/arch/riscv/include/asm/kvm_vcpu_timer.h new file mode 100644 index 000000000..375281eb4 --- /dev/null +++ b/arch/riscv/include/asm/kvm_vcpu_timer.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Atish Patra atish.patra@wdc.com + */ + +#ifndef __KVM_VCPU_RISCV_TIMER_H +#define __KVM_VCPU_RISCV_TIMER_H + +#include <linux/hrtimer.h> + +struct kvm_guest_timer { + /* Mult & Shift values to get nanoseconds from cycles */ + u32 nsec_mult; + u32 nsec_shift; + /* Time delta value */ + u64 time_delta; +}; + +struct kvm_vcpu_timer { + /* Flag for whether init is done */ + bool init_done; + /* Flag for whether timer event is configured */ + bool next_set; + /* Next timer event cycles */ + u64 next_cycles; + /* Underlying hrtimer instance */ + struct hrtimer hrt; +}; + +int kvm_riscv_vcpu_timer_next_event(struct kvm_vcpu *vcpu, u64 ncycles); +int kvm_riscv_vcpu_get_reg_timer(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg); +int kvm_riscv_vcpu_set_reg_timer(struct kvm_vcpu *vcpu, + const struct kvm_one_reg *reg); +int kvm_riscv_vcpu_timer_init(struct kvm_vcpu *vcpu); +int kvm_riscv_vcpu_timer_deinit(struct kvm_vcpu *vcpu); +int kvm_riscv_vcpu_timer_reset(struct kvm_vcpu *vcpu); +void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu); +int kvm_riscv_guest_timer_init(struct kvm *kvm); + +#endif diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h index f7e9dc388..00196a13d 100644 --- a/arch/riscv/include/uapi/asm/kvm.h +++ b/arch/riscv/include/uapi/asm/kvm.h @@ -74,6 +74,18 @@ struct kvm_riscv_csr { unsigned long scounteren; };
+/* TIMER registers for KVM_GET_ONE_REG and KVM_SET_ONE_REG */ +struct kvm_riscv_timer { + u64 frequency; + u64 time; + u64 compare; + u64 state; +}; + +/* Possible states for kvm_riscv_timer */ +#define KVM_RISCV_TIMER_STATE_OFF 0 +#define KVM_RISCV_TIMER_STATE_ON 1 + #define KVM_REG_SIZE(id) \ (1U << (((id) & KVM_REG_SIZE_MASK) >> KVM_REG_SIZE_SHIFT))
@@ -96,6 +108,11 @@ struct kvm_riscv_csr { #define KVM_REG_RISCV_CSR_REG(name) \ (offsetof(struct kvm_riscv_csr, name) / sizeof(unsigned long))
+/* Timer registers are mapped as type 4 */ +#define KVM_REG_RISCV_TIMER (0x04 << KVM_REG_RISCV_TYPE_SHIFT) +#define KVM_REG_RISCV_TIMER_REG(name) \ + (offsetof(struct kvm_riscv_timer, name) / sizeof(u64)) + #endif
#endif /* __LINUX_KVM_RISCV_H */ diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile index b32f60edf..a034826f9 100644 --- a/arch/riscv/kvm/Makefile +++ b/arch/riscv/kvm/Makefile @@ -10,6 +10,6 @@ ccflags-y := -Ivirt/kvm -Iarch/riscv/kvm kvm-objs := $(common-objs-y)
kvm-objs += main.o vm.o vmid.o tlb.o mmu.o -kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o +kvm-objs += vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
obj-$(CONFIG_KVM) += kvm.o diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 7192b6edd..45ff6761b 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -55,6 +55,8 @@ static void kvm_riscv_reset_vcpu(struct kvm_vcpu *vcpu)
memcpy(cntx, reset_cntx, sizeof(*cntx));
+ kvm_riscv_vcpu_timer_reset(vcpu); + WRITE_ONCE(vcpu->arch.irqs_pending, 0); WRITE_ONCE(vcpu->arch.irqs_pending_mask, 0); } @@ -82,6 +84,9 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) cntx->hstatus |= HSTATUS_SPVP; cntx->hstatus |= HSTATUS_SPV;
+ /* Setup VCPU timer */ + kvm_riscv_vcpu_timer_init(vcpu); + /* Reset VCPU */ kvm_riscv_reset_vcpu(vcpu);
@@ -99,6 +104,9 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) { + /* Cleanup VCPU timer */ + kvm_riscv_vcpu_timer_deinit(vcpu); + /* Flush the pages pre-allocated for Stage2 page table mappings */ kvm_riscv_stage2_flush_cache(vcpu); } @@ -349,6 +357,8 @@ static int kvm_riscv_vcpu_set_reg(struct kvm_vcpu *vcpu, return kvm_riscv_vcpu_set_reg_core(vcpu, reg); else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR) return kvm_riscv_vcpu_set_reg_csr(vcpu, reg); + else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_TIMER) + return kvm_riscv_vcpu_set_reg_timer(vcpu, reg);
return -EINVAL; } @@ -362,6 +372,8 @@ static int kvm_riscv_vcpu_get_reg(struct kvm_vcpu *vcpu, return kvm_riscv_vcpu_get_reg_core(vcpu, reg); else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_CSR) return kvm_riscv_vcpu_get_reg_csr(vcpu, reg); + else if ((reg->id & KVM_REG_RISCV_TYPE_MASK) == KVM_REG_RISCV_TIMER) + return kvm_riscv_vcpu_get_reg_timer(vcpu, reg);
return -EINVAL; } @@ -594,6 +606,8 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
kvm_riscv_stage2_update_hgatp(vcpu);
+ kvm_riscv_vcpu_timer_restore(vcpu); + vcpu->cpu = cpu; }
diff --git a/arch/riscv/kvm/vcpu_timer.c b/arch/riscv/kvm/vcpu_timer.c new file mode 100644 index 000000000..ddd0ce727 --- /dev/null +++ b/arch/riscv/kvm/vcpu_timer.c @@ -0,0 +1,225 @@ +// 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; +} + +int kvm_riscv_vcpu_timer_next_event(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_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 -EINVAL; + + 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 -EINVAL; + }; + + 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 -EINVAL; + + if (copy_from_user(®_val, uaddr, KVM_REG_SIZE(reg->id))) + return -EFAULT; + + switch (reg_num) { + case KVM_REG_RISCV_TIMER_REG(frequency): + ret = -EOPNOTSUPP; + 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 = -EINVAL; + 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->hrt.function = kvm_riscv_vcpu_hrtimer_expired; + t->init_done = true; + t->next_set = false; + + 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) +{ + return kvm_riscv_vcpu_timer_cancel(&vcpu->arch.timer); +} + +void kvm_riscv_vcpu_timer_restore(struct kvm_vcpu *vcpu) +{ + struct kvm_guest_timer *gt = &vcpu->kvm->arch.timer; + +#ifdef CONFIG_64BIT + csr_write(CSR_HTIMEDELTA, gt->time_delta); +#else + csr_write(CSR_HTIMEDELTA, (u32)(gt->time_delta)); + csr_write(CSR_HTIMEDELTAH, (u32)(gt->time_delta >> 32)); +#endif +} + +int 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(); + + return 0; +} diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index 00a1a8800..253c45ee2 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -26,7 +26,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) return r; }
- return 0; + return kvm_riscv_guest_timer_init(kvm); }
void kvm_arch_destroy_vm(struct kvm *kvm) diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c index c51c5ed15..8e73c0a23 100644 --- a/drivers/clocksource/timer-riscv.c +++ b/drivers/clocksource/timer-riscv.c @@ -13,6 +13,7 @@ #include <linux/delay.h> #include <linux/irq.h> #include <linux/irqdomain.h> +#include <linux/module.h> #include <linux/sched_clock.h> #include <linux/io-64-nonatomic-lo-hi.h> #include <linux/interrupt.h> @@ -79,6 +80,13 @@ static int riscv_timer_dying_cpu(unsigned int cpu) return 0; }
+void riscv_cs_get_mult_shift(u32 *mult, u32 *shift) +{ + *mult = riscv_clocksource.mult; + *shift = riscv_clocksource.shift; +} +EXPORT_SYMBOL_GPL(riscv_cs_get_mult_shift); + /* called directly from the low-level interrupt handler */ static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id) { diff --git a/include/clocksource/timer-riscv.h b/include/clocksource/timer-riscv.h new file mode 100644 index 000000000..d7f455754 --- /dev/null +++ b/include/clocksource/timer-riscv.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + * + * Authors: + * Atish Patra atish.patra@wdc.com + */ + +#ifndef __TIMER_RISCV_H +#define __TIMER_RISCV_H + +#include <linux/types.h> + +extern void riscv_cs_get_mult_shift(u32 *mult, u32 *shift); + +#endif