| Message ID | 20170829093902.15379-5-cdall@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Aug 29 2017 at 11:39:02 am BST, Christoffer Dall <cdall@linaro.org> wrote: > The GIC sometimes need to sample the physical line of a mapped > interrupt. As we know this to be notoriously slow, provide a callback > function for devices (such as the timer) which can do this much faster > than talking to the distributor, for example by comparing a few > in-memory values. Fall back to the good old method of poking the > physical GIC if no callback is provided. > > Signed-off-by: Christoffer Dall <cdall@linaro.org> > --- > include/kvm/arm_vgic.h | 13 ++++++++++++- > virt/kvm/arm/arch_timer.c | 16 +++++++++++++++- > virt/kvm/arm/vgic/vgic.c | 7 ++++++- > 3 files changed, 33 insertions(+), 3 deletions(-) > > diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h > index 53f631b..a52990b 100644 > --- a/include/kvm/arm_vgic.h > +++ b/include/kvm/arm_vgic.h > @@ -125,6 +125,17 @@ struct vgic_irq { > u8 priority; > enum vgic_irq_config config; /* Level or edge */ > > + /* > + * Callback function pointer to in-kernel devices that can tell us the > + * state of the input level of mapped level-triggered IRQ faster than > + * peaking into the physical GIC. > + * > + * Always called in non-preemptible section and the functions can use > + * kvm_arm_get_running_vcpu() to get the vcpu pointer for private > + * IRQs. > + */ > + bool (*get_input_level)(int vintid); > + > void *owner; /* Opaque pointer to reserve an interrupt > for in-kernel devices. */ > }; > @@ -309,7 +320,7 @@ void kvm_vgic_init_cpu_hardware(void); > int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, > bool level, void *owner); > int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, > - u32 vintid); > + u32 vintid, bool (*callback)(int vindid)); > int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid); > bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid); > > diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c > index b24e2f7..82169ef 100644 > --- a/virt/kvm/arm/arch_timer.c > +++ b/virt/kvm/arm/arch_timer.c > @@ -643,6 +643,19 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu) > return true; > } > > +static bool timer_get_input_level(int vintid) > +{ > + struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu(); > + struct arch_timer_context *timer; > + > + if (vintid == vcpu_vtimer(vcpu)->irq.irq) > + timer = vcpu_vtimer(vcpu); > + else > + BUG(); /* We only map the vtimer so far */ > + > + return kvm_timer_should_fire(timer); > +} > + > int kvm_timer_enable(struct kvm_vcpu *vcpu) > { > struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; > @@ -664,7 +677,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) > return -EINVAL; > } > > - ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq); > + ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq, > + &timer_get_input_level); nit: no need for a & here. > if (ret) > return ret; > > diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c > index e3ce2fa..0466c10 100644 > --- a/virt/kvm/arm/vgic/vgic.c > +++ b/virt/kvm/arm/vgic/vgic.c > @@ -147,6 +147,9 @@ bool vgic_irq_line_level(struct vgic_irq *irq) > > BUG_ON(!irq->hw); > > + if (irq->get_input_level) > + return irq->get_input_level(irq->intid); > + > WARN_ON(irq_get_irqchip_state(irq->host_irq, > IRQCHIP_STATE_PENDING, > &line_level)); > @@ -429,7 +432,7 @@ 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) > + u32 vintid, bool (*callback)(int vindid)) nit #2: "callback" is a very non-descriptive name for a callback... ;-) How about calling it "get_input_level", matching the vgic_irq field? > { > struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid); > struct irq_desc *desc; > @@ -456,6 +459,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, > irq->hw = true; > irq->host_irq = host_irq; > irq->hwintid = data->hwirq; > + irq->get_input_level = callback; > > out: > spin_unlock(&irq->irq_lock); > @@ -476,6 +480,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid) > spin_lock(&irq->irq_lock); > irq->hw = false; > irq->hwintid = 0; > + irq->get_input_level = NULL; > spin_unlock(&irq->irq_lock); > vgic_put_irq(vcpu->kvm, irq); Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> M.
On Sat, Sep 02, 2017 at 12:20:34PM +0100, Marc Zyngier wrote: > On Tue, Aug 29 2017 at 11:39:02 am BST, Christoffer Dall <cdall@linaro.org> wrote: > > The GIC sometimes need to sample the physical line of a mapped > > interrupt. As we know this to be notoriously slow, provide a callback > > function for devices (such as the timer) which can do this much faster > > than talking to the distributor, for example by comparing a few > > in-memory values. Fall back to the good old method of poking the > > physical GIC if no callback is provided. > > > > Signed-off-by: Christoffer Dall <cdall@linaro.org> > > --- > > include/kvm/arm_vgic.h | 13 ++++++++++++- > > virt/kvm/arm/arch_timer.c | 16 +++++++++++++++- > > virt/kvm/arm/vgic/vgic.c | 7 ++++++- > > 3 files changed, 33 insertions(+), 3 deletions(-) > > > > diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h > > index 53f631b..a52990b 100644 > > --- a/include/kvm/arm_vgic.h > > +++ b/include/kvm/arm_vgic.h > > @@ -125,6 +125,17 @@ struct vgic_irq { > > u8 priority; > > enum vgic_irq_config config; /* Level or edge */ > > > > + /* > > + * Callback function pointer to in-kernel devices that can tell us the > > + * state of the input level of mapped level-triggered IRQ faster than > > + * peaking into the physical GIC. > > + * > > + * Always called in non-preemptible section and the functions can use > > + * kvm_arm_get_running_vcpu() to get the vcpu pointer for private > > + * IRQs. > > + */ > > + bool (*get_input_level)(int vintid); > > + > > void *owner; /* Opaque pointer to reserve an interrupt > > for in-kernel devices. */ > > }; > > @@ -309,7 +320,7 @@ void kvm_vgic_init_cpu_hardware(void); > > int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, > > bool level, void *owner); > > int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, > > - u32 vintid); > > + u32 vintid, bool (*callback)(int vindid)); > > int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid); > > bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid); > > > > diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c > > index b24e2f7..82169ef 100644 > > --- a/virt/kvm/arm/arch_timer.c > > +++ b/virt/kvm/arm/arch_timer.c > > @@ -643,6 +643,19 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu) > > return true; > > } > > > > +static bool timer_get_input_level(int vintid) > > +{ > > + struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu(); > > + struct arch_timer_context *timer; > > + > > + if (vintid == vcpu_vtimer(vcpu)->irq.irq) > > + timer = vcpu_vtimer(vcpu); > > + else > > + BUG(); /* We only map the vtimer so far */ > > + > > + return kvm_timer_should_fire(timer); > > +} > > + > > int kvm_timer_enable(struct kvm_vcpu *vcpu) > > { > > struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; > > @@ -664,7 +677,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) > > return -EINVAL; > > } > > > > - ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq); > > + ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq, > > + &timer_get_input_level); > > nit: no need for a & here. > > > if (ret) > > return ret; > > > > diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c > > index e3ce2fa..0466c10 100644 > > --- a/virt/kvm/arm/vgic/vgic.c > > +++ b/virt/kvm/arm/vgic/vgic.c > > @@ -147,6 +147,9 @@ bool vgic_irq_line_level(struct vgic_irq *irq) > > > > BUG_ON(!irq->hw); > > > > + if (irq->get_input_level) > > + return irq->get_input_level(irq->intid); > > + > > WARN_ON(irq_get_irqchip_state(irq->host_irq, > > IRQCHIP_STATE_PENDING, > > &line_level)); > > @@ -429,7 +432,7 @@ 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) > > + u32 vintid, bool (*callback)(int vindid)) > > nit #2: "callback" is a very non-descriptive name for a callback... ;-) > How about calling it "get_input_level", matching the vgic_irq field? Yeah, totally. > > > { > > struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid); > > struct irq_desc *desc; > > @@ -456,6 +459,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, > > irq->hw = true; > > irq->host_irq = host_irq; > > irq->hwintid = data->hwirq; > > + irq->get_input_level = callback; > > > > out: > > spin_unlock(&irq->irq_lock); > > @@ -476,6 +480,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid) > > spin_lock(&irq->irq_lock); > > irq->hw = false; > > irq->hwintid = 0; > > + irq->get_input_level = NULL; > > spin_unlock(&irq->irq_lock); > > vgic_put_irq(vcpu->kvm, irq); > > Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> > Thanks! -Christoffer
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h index 53f631b..a52990b 100644 --- a/include/kvm/arm_vgic.h +++ b/include/kvm/arm_vgic.h @@ -125,6 +125,17 @@ struct vgic_irq { u8 priority; enum vgic_irq_config config; /* Level or edge */ + /* + * Callback function pointer to in-kernel devices that can tell us the + * state of the input level of mapped level-triggered IRQ faster than + * peaking into the physical GIC. + * + * Always called in non-preemptible section and the functions can use + * kvm_arm_get_running_vcpu() to get the vcpu pointer for private + * IRQs. + */ + bool (*get_input_level)(int vintid); + void *owner; /* Opaque pointer to reserve an interrupt for in-kernel devices. */ }; @@ -309,7 +320,7 @@ void kvm_vgic_init_cpu_hardware(void); int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid, bool level, void *owner); int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, - u32 vintid); + u32 vintid, bool (*callback)(int vindid)); int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid); bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid); diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c index b24e2f7..82169ef 100644 --- a/virt/kvm/arm/arch_timer.c +++ b/virt/kvm/arm/arch_timer.c @@ -643,6 +643,19 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu) return true; } +static bool timer_get_input_level(int vintid) +{ + struct kvm_vcpu *vcpu = kvm_arm_get_running_vcpu(); + struct arch_timer_context *timer; + + if (vintid == vcpu_vtimer(vcpu)->irq.irq) + timer = vcpu_vtimer(vcpu); + else + BUG(); /* We only map the vtimer so far */ + + return kvm_timer_should_fire(timer); +} + int kvm_timer_enable(struct kvm_vcpu *vcpu) { struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu; @@ -664,7 +677,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu) return -EINVAL; } - ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq); + ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq, + &timer_get_input_level); if (ret) return ret; diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c index e3ce2fa..0466c10 100644 --- a/virt/kvm/arm/vgic/vgic.c +++ b/virt/kvm/arm/vgic/vgic.c @@ -147,6 +147,9 @@ bool vgic_irq_line_level(struct vgic_irq *irq) BUG_ON(!irq->hw); + if (irq->get_input_level) + return irq->get_input_level(irq->intid); + WARN_ON(irq_get_irqchip_state(irq->host_irq, IRQCHIP_STATE_PENDING, &line_level)); @@ -429,7 +432,7 @@ 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) + u32 vintid, bool (*callback)(int vindid)) { struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid); struct irq_desc *desc; @@ -456,6 +459,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq, irq->hw = true; irq->host_irq = host_irq; irq->hwintid = data->hwirq; + irq->get_input_level = callback; out: spin_unlock(&irq->irq_lock); @@ -476,6 +480,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid) spin_lock(&irq->irq_lock); irq->hw = false; irq->hwintid = 0; + irq->get_input_level = NULL; spin_unlock(&irq->irq_lock); vgic_put_irq(vcpu->kvm, irq);
The GIC sometimes need to sample the physical line of a mapped interrupt. As we know this to be notoriously slow, provide a callback function for devices (such as the timer) which can do this much faster than talking to the distributor, for example by comparing a few in-memory values. Fall back to the good old method of poking the physical GIC if no callback is provided. Signed-off-by: Christoffer Dall <cdall@linaro.org> --- include/kvm/arm_vgic.h | 13 ++++++++++++- virt/kvm/arm/arch_timer.c | 16 +++++++++++++++- virt/kvm/arm/vgic/vgic.c | 7 ++++++- 3 files changed, 33 insertions(+), 3 deletions(-)