Re: [PATCH 46/59] KVM: arm64: nv: arch_timer: Support hyp timer emulation

Alexandru Elisei
2019-07-10T16:23:30Z

On 6/21/19 10:38 AM, Marc Zyngier wrote:
> From: Christoffer Dall <christoffer.dall@arm.com>
>
> Emulating EL2 also means emulating the EL2 timers. To do so, we expand
> our timer framework to deal with at most 4 timers. At any given time,
> two timers are using the HW timers, and the two others are purely
> emulated.
>
> The role of deciding which is which at any given time is left to a
> mapping function which is called every time we need to make such a
> decision.
>
> Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
> arch/arm/include/asm/kvm_emulate.h | 2 +
> include/kvm/arm_arch_timer.h | 5 ++
> include/kvm/arm_vgic.h | 1 +
> virt/kvm/arm/arch_timer.c | 122 ++++++++++++++++++++++++++++-
> virt/kvm/arm/trace.h | 6 +-
> virt/kvm/arm/vgic/vgic.c | 15 ++++
> 6 files changed, 147 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/include/asm/kvm_emulate.h b/arch/arm/include/asm/kvm_emulate.h
> index 6b7644a383f6..865ce545b465 100644
> --- a/arch/arm/include/asm/kvm_emulate.h
> +++ b/arch/arm/include/asm/kvm_emulate.h
> @@ -333,4 +333,6 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu,
>
> static inline void vcpu_ptrauth_setup_lazy(struct kvm_vcpu *vcpu) {}
>
> +static inline bool is_hyp_ctxt(struct kvm_vcpu *vcpu) { return false; }
> +
> #endif /* __ARM_KVM_EMULATE_H__ */
> diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
> index d120e6c323e7..3a5d9255120e 100644
> --- a/include/kvm/arm_arch_timer.h
> +++ b/include/kvm/arm_arch_timer.h
> @@ -13,6 +13,8 @@
> enum kvm_arch_timers {
> TIMER_PTIMER,
> TIMER_VTIMER,
> + TIMER_HVTIMER,
> + TIMER_HPTIMER,
> NR_KVM_TIMERS
> };
>
> @@ -54,6 +56,7 @@ struct arch_timer_context {
> struct timer_map {
> struct arch_timer_context *direct_vtimer;
> struct arch_timer_context *direct_ptimer;
> + struct arch_timer_context *emul_vtimer;
> struct arch_timer_context *emul_ptimer;
> };
>
> @@ -98,6 +101,8 @@ bool kvm_arch_timer_get_input_level(int vintid);
> #define vcpu_get_timer(v,t) (&vcpu_timer(v)->timers[(t)])
> #define vcpu_vtimer(v) (&(v)->arch.timer_cpu.timers[TIMER_VTIMER])
> #define vcpu_ptimer(v) (&(v)->arch.timer_cpu.timers[TIMER_PTIMER])
> +#define vcpu_hvtimer(v) (&(v)->arch.timer_cpu.timers[TIMER_HVTIMER])
> +#define vcpu_hptimer(v) (&(v)->arch.timer_cpu.timers[TIMER_HPTIMER])
>
> #define arch_timer_ctx_index(ctx) ((ctx) - vcpu_timer((ctx)->vcpu)->timers)
>
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index c36c86f1ec9a..7fc3b413b3de 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -355,6 +355,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> u32 vintid, bool (*get_input_level)(int vindid));
> int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);
> +int kvm_vgic_get_map(struct kvm_vcpu *vcpu, unsigned int vintid);
> bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);
>
> int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 089441a07ed7..3d84c240071d 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -15,6 +15,7 @@
> #include <asm/arch_timer.h>
> #include <asm/kvm_emulate.h>
> #include <asm/kvm_hyp.h>
> +#include <asm/kvm_nested.h>
>
> #include <kvm/arm_vgic.h>
> #include <kvm/arm_arch_timer.h>
> @@ -39,6 +40,16 @@ static const struct kvm_irq_level default_vtimer_irq = {
> .level = 1,
> };
>
> +static const struct kvm_irq_level default_hptimer_irq = {
> + .irq = 26,
> + .level = 1,
> +};
> +
> +static const struct kvm_irq_level default_hvtimer_irq = {
> + .irq = 28,
> + .level = 1,
> +};
> +
> static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx);
> static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
> struct arch_timer_context *timer_ctx);
> @@ -58,13 +69,27 @@ u64 kvm_phys_timer_read(void)
>
> static void get_timer_map(struct kvm_vcpu *vcpu, struct timer_map *map)
> {
> - if (has_vhe()) {
> + if (nested_virt_in_use(vcpu)) {
> + if (is_hyp_ctxt(vcpu)) {
> + map->direct_vtimer = vcpu_hvtimer(vcpu);
> + map->direct_ptimer = vcpu_hptimer(vcpu);
> + map->emul_vtimer = vcpu_vtimer(vcpu);
> + map->emul_ptimer = vcpu_ptimer(vcpu);
> + } else {
> + map->direct_vtimer = vcpu_vtimer(vcpu);
> + map->direct_ptimer = vcpu_ptimer(vcpu);
> + map->emul_vtimer = vcpu_hvtimer(vcpu);
> + map->emul_ptimer = vcpu_hptimer(vcpu);
> + }
> + } else if (has_vhe()) {
> map->direct_vtimer = vcpu_vtimer(vcpu);
> map->direct_ptimer = vcpu_ptimer(vcpu);
> + map->emul_vtimer = NULL;
> map->emul_ptimer = NULL;
> } else {
> map->direct_vtimer = vcpu_vtimer(vcpu);
> map->direct_ptimer = NULL;
> + map->emul_vtimer = NULL;
> map->emul_ptimer = vcpu_ptimer(vcpu);
> }
>
> @@ -237,9 +262,11 @@ static bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx)
>
> switch (index) {
> case TIMER_VTIMER:
> + case TIMER_HVTIMER:
> cnt_ctl = read_sysreg_el0(SYS_CNTV_CTL);
> break;
> case TIMER_PTIMER:
> + case TIMER_HPTIMER:
> cnt_ctl = read_sysreg_el0(SYS_CNTP_CTL);
> break;
> case NR_KVM_TIMERS:
> @@ -270,6 +297,7 @@ bool kvm_timer_is_pending(struct kvm_vcpu *vcpu)
>
> return kvm_timer_should_fire(map.direct_vtimer) ||
> kvm_timer_should_fire(map.direct_ptimer) ||
> + kvm_timer_should_fire(map.emul_vtimer) ||
> kvm_timer_should_fire(map.emul_ptimer);
> }
>
> @@ -349,6 +377,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
>
> switch (index) {
> case TIMER_VTIMER:
> + case TIMER_HVTIMER:
> ctx->cnt_ctl = read_sysreg_el0(SYS_CNTV_CTL);
> ctx->cnt_cval = read_sysreg_el0(SYS_CNTV_CVAL);
>
> @@ -358,6 +387,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
>
> break;
> case TIMER_PTIMER:
> + case TIMER_HPTIMER:
> ctx->cnt_ctl = read_sysreg_el0(SYS_CNTP_CTL);
> ctx->cnt_cval = read_sysreg_el0(SYS_CNTP_CVAL);
>
> @@ -395,6 +425,7 @@ static void kvm_timer_blocking(struct kvm_vcpu *vcpu)
> */
> if (!kvm_timer_irq_can_fire(map.direct_vtimer) &&
> !kvm_timer_irq_can_fire(map.direct_ptimer) &&
> + !kvm_timer_irq_can_fire(map.emul_vtimer) &&
> !kvm_timer_irq_can_fire(map.emul_ptimer))
> return;
>
> @@ -428,11 +459,13 @@ static void timer_restore_state(struct arch_timer_context *ctx)
>
> switch (index) {
> case TIMER_VTIMER:
> + case TIMER_HVTIMER:
> write_sysreg_el0(ctx->cnt_cval, SYS_CNTV_CVAL);
> isb();
> write_sysreg_el0(ctx->cnt_ctl, SYS_CNTV_CTL);
> break;
> case TIMER_PTIMER:
> + case TIMER_HPTIMER:
> write_sysreg_el0(ctx->cnt_cval, SYS_CNTP_CVAL);
> isb();
> write_sysreg_el0(ctx->cnt_ctl, SYS_CNTP_CTL);
> @@ -519,6 +552,40 @@ static void kvm_timer_vcpu_load_nogic(struct kvm_vcpu *vcpu)
> enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
> }
>
> +static void kvm_timer_vcpu_load_nested_switch(struct kvm_vcpu *vcpu,
> + struct timer_map *map)
> +{
> + int hw, ret;
> +
> + if (!irqchip_in_kernel(vcpu->kvm))
> + return;
> +
> + /*
> + * We only ever unmap the vtimer irq on a VHE system that runs nested
> + * virtualization, in which case we have both a valid emul_vtimer,
> + * emul_ptimer, direct_vtimer, and direct_ptimer.
> + *
> + * Since this is called from kvm_timer_vcpu_load(), a change between
> + * vEL2 and vEL1/0 will have just happened, and the timer_map will
> + * represent this, and therefore we switch the emul/direct mappings
> + * below.
> + */
> + hw = kvm_vgic_get_map(vcpu, map->direct_vtimer->irq.irq);
> + if (hw < 0) {
> + kvm_vgic_unmap_phys_irq(vcpu, map->emul_vtimer->irq.irq);
> + kvm_vgic_unmap_phys_irq(vcpu, map->emul_ptimer->irq.irq);
> +
> + ret = kvm_vgic_map_phys_irq(vcpu,
> + map->direct_vtimer->host_timer_irq,
> + map->direct_vtimer->irq.irq,
> + kvm_arch_timer_get_input_level);
> + ret = kvm_vgic_map_phys_irq(vcpu,
> + map->direct_ptimer->host_timer_irq,
> + map->direct_ptimer->irq.irq,
> + kvm_arch_timer_get_input_level);
> + }
> +}
> +
> void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
> {
> struct arch_timer_cpu *timer = vcpu_timer(vcpu);
> @@ -530,6 +597,8 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
> get_timer_map(vcpu, &map);
>
> if (static_branch_likely(&has_gic_active_state)) {
> + kvm_timer_vcpu_load_nested_switch(vcpu, &map);

Would it be possible for this be a conditional call that depends on
nested_virt_in_use(vcpu), since that's the only situation where we change the
direct_vtimer when we switch from vEL1 to vEL2 or viceversa?

Thanks,
Alex
> +
> kvm_timer_vcpu_load_gic(map.direct_vtimer);
> if (map.direct_ptimer)
> kvm_timer_vcpu_load_gic(map.direct_ptimer);
> @@ -545,6 +614,8 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
> if (map.direct_ptimer)
> timer_restore_state(map.direct_ptimer);
>
> + if (map.emul_vtimer)
> + timer_emulate(map.emul_vtimer);
> if (map.emul_ptimer)
> timer_emulate(map.emul_ptimer);
> }
> @@ -589,6 +660,8 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
> * In any case, we re-schedule the hrtimer for the physical timer when
> * coming back to the VCPU thread in kvm_timer_vcpu_load().
> */
> + if (map.emul_vtimer)
> + soft_timer_cancel(&map.emul_vtimer->hrtimer);
> if (map.emul_ptimer)
> soft_timer_cancel(&map.emul_ptimer->hrtimer);
>
> @@ -649,10 +722,14 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
> */
> vcpu_vtimer(vcpu)->cnt_ctl = 0;
> vcpu_ptimer(vcpu)->cnt_ctl = 0;
> + vcpu_hvtimer(vcpu)->cnt_ctl = 0;
> + vcpu_hptimer(vcpu)->cnt_ctl = 0;
>
> if (timer->enabled) {
> kvm_timer_update_irq(vcpu, false, vcpu_vtimer(vcpu));
> kvm_timer_update_irq(vcpu, false, vcpu_ptimer(vcpu));
> + kvm_timer_update_irq(vcpu, false, vcpu_hvtimer(vcpu));
> + kvm_timer_update_irq(vcpu, false, vcpu_hptimer(vcpu));
>
> if (irqchip_in_kernel(vcpu->kvm)) {
> kvm_vgic_reset_mapped_irq(vcpu, map.direct_vtimer->irq.irq);
> @@ -661,6 +738,8 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
> }
> }
>
> + if (map.emul_vtimer)
> + soft_timer_cancel(&map.emul_vtimer->hrtimer);
> if (map.emul_ptimer)
> soft_timer_cancel(&map.emul_ptimer->hrtimer);
>
> @@ -691,30 +770,46 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
> struct arch_timer_cpu *timer = vcpu_timer(vcpu);
> struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
> struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
> + struct arch_timer_context *hvtimer = vcpu_hvtimer(vcpu);
> + struct arch_timer_context *hptimer = vcpu_hptimer(vcpu);
>
> /* Synchronize cntvoff across all vtimers of a VM. */
> update_vtimer_cntvoff(vcpu, kvm_phys_timer_read());
> ptimer->cntvoff = 0;
> + hvtimer->cntvoff = 0;
> + hptimer->cntvoff = 0;
>
> hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> timer->bg_timer.function = kvm_bg_timer_expire;
>
> hrtimer_init(&vtimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> hrtimer_init(&ptimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> + hrtimer_init(&hvtimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> + hrtimer_init(&hptimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
> vtimer->hrtimer.function = kvm_hrtimer_expire;
> ptimer->hrtimer.function = kvm_hrtimer_expire;
> + hvtimer->hrtimer.function = kvm_hrtimer_expire;
> + hptimer->hrtimer.function = kvm_hrtimer_expire;
>
> vtimer->irq.irq = default_vtimer_irq.irq;
> ptimer->irq.irq = default_ptimer_irq.irq;
> + hvtimer->irq.irq = default_hvtimer_irq.irq;
> + hptimer->irq.irq = default_hptimer_irq.irq;
>
> vtimer->host_timer_irq = host_vtimer_irq;
> ptimer->host_timer_irq = host_ptimer_irq;
> + hvtimer->host_timer_irq = host_vtimer_irq;
> + hptimer->host_timer_irq = host_ptimer_irq;
>
> vtimer->host_timer_irq_flags = host_vtimer_irq_flags;
> ptimer->host_timer_irq_flags = host_ptimer_irq_flags;
> + hvtimer->host_timer_irq_flags = host_vtimer_irq_flags;
> + hptimer->host_timer_irq_flags = host_ptimer_irq_flags;
>
> vtimer->vcpu = vcpu;
> ptimer->vcpu = vcpu;
> + hvtimer->vcpu = vcpu;
> + hptimer->vcpu = vcpu;
> }
>
> static void kvm_timer_init_interrupt(void *info)
> @@ -997,7 +1092,7 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
>
> static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
> {
> - int vtimer_irq, ptimer_irq;
> + int vtimer_irq, ptimer_irq, hvtimer_irq, hptimer_irq;
> int i, ret;
>
> vtimer_irq = vcpu_vtimer(vcpu)->irq.irq;
> @@ -1010,9 +1105,21 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
> if (ret)
> return false;
>
> + hvtimer_irq = vcpu_hvtimer(vcpu)->irq.irq;
> + ret = kvm_vgic_set_owner(vcpu, hvtimer_irq, vcpu_hvtimer(vcpu));
> + if (ret)
> + return false;
> +
> + hptimer_irq = vcpu_hptimer(vcpu)->irq.irq;
> + ret = kvm_vgic_set_owner(vcpu, hptimer_irq, vcpu_hptimer(vcpu));
> + if (ret)
> + return false;
> +
> kvm_for_each_vcpu(i, vcpu, vcpu->kvm) {
> if (vcpu_vtimer(vcpu)->irq.irq != vtimer_irq ||
> - vcpu_ptimer(vcpu)->irq.irq != ptimer_irq)
> + vcpu_ptimer(vcpu)->irq.irq != ptimer_irq ||
> + vcpu_hvtimer(vcpu)->irq.irq != hvtimer_irq ||
> + vcpu_hptimer(vcpu)->irq.irq != hptimer_irq)
> return false;
> }
>
> @@ -1028,6 +1135,10 @@ bool kvm_arch_timer_get_input_level(int vintid)
> timer = vcpu_vtimer(vcpu);
> else if (vintid == vcpu_ptimer(vcpu)->irq.irq)
> timer = vcpu_ptimer(vcpu);
> + else if (vintid == vcpu_hvtimer(vcpu)->irq.irq)
> + timer = vcpu_hvtimer(vcpu);
> + else if (vintid == vcpu_hptimer(vcpu)->irq.irq)
> + timer = vcpu_hptimer(vcpu);
> else
> BUG();
>
> @@ -1109,6 +1220,7 @@ static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
> kvm_for_each_vcpu(i, vcpu, kvm) {
> vcpu_vtimer(vcpu)->irq.irq = vtimer_irq;
> vcpu_ptimer(vcpu)->irq.irq = ptimer_irq;
> + /* TODO: Add support for hv/hp timers */
> }
> }
>
> @@ -1119,6 +1231,8 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
> struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
> int irq;
>
> + /* TODO: Add support for hv/hp timers */
> +
> if (!irqchip_in_kernel(vcpu->kvm))
> return -EINVAL;
>
> @@ -1151,6 +1265,8 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
> struct arch_timer_context *timer;
> int irq;
>
> + /* TODO: Add support for hv/hp timers */
> +
> switch (attr->attr) {
> case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
> timer = vcpu_vtimer(vcpu);
> diff --git a/virt/kvm/arm/trace.h b/virt/kvm/arm/trace.h
> index 204d210d01c2..3b08cc0376f4 100644
> --- a/virt/kvm/arm/trace.h
> +++ b/virt/kvm/arm/trace.h
> @@ -271,6 +271,7 @@ TRACE_EVENT(kvm_get_timer_map,
> __field( unsigned long, vcpu_id )
> __field( int, direct_vtimer )
> __field( int, direct_ptimer )
> + __field( int, emul_vtimer )
> __field( int, emul_ptimer )
> ),
>
> @@ -279,14 +280,17 @@ TRACE_EVENT(kvm_get_timer_map,
> __entry->direct_vtimer = arch_timer_ctx_index(map->direct_vtimer);
> __entry->direct_ptimer =
> (map->direct_ptimer) ? arch_timer_ctx_index(map->direct_ptimer) : -1;
> + __entry->emul_vtimer =
> + (map->emul_vtimer) ? arch_timer_ctx_index(map->emul_vtimer) : -1;
> __entry->emul_ptimer =
> (map->emul_ptimer) ? arch_timer_ctx_index(map->emul_ptimer) : -1;
> ),
>
> - TP_printk("VCPU: %ld, dv: %d, dp: %d, ep: %d",
> + TP_printk("VCPU: %ld, dv: %d, dp: %d, ev: %d, ep: %d",
> __entry->vcpu_id,
> __entry->direct_vtimer,
> __entry->direct_ptimer,
> + __entry->emul_vtimer,
> __entry->emul_ptimer)
> );
>
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index 191deccf60bf..1c5b4dbd33e4 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
> @@ -569,6 +569,21 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
> return 0;
> }
>
> +int kvm_vgic_get_map(struct kvm_vcpu *vcpu, unsigned int vintid)
> +{
> + struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
> + unsigned long flags;
> + int ret = -1;
> +
> + raw_spin_lock_irqsave(&irq->irq_lock, flags);
> + if (irq->hw)
> + ret = irq->hwintid;
> + raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
> +
> + vgic_put_irq(vcpu->kvm, irq);
> + return ret;
> +}
> +
> /**
> * kvm_vgic_set_owner - Set the owner of an interrupt for a VM
> *