Re: [PATCH v9 3/3] x86, apicv: add virtual interrupt delivery support

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Hi,

Getting into good shape.

On Thu, Jan 10, 2013 at 03:26:08PM +0800, Yang Zhang wrote:
> From: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> 
> Virtual interrupt delivery avoids KVM to inject vAPIC interrupts
> manually, which is fully taken care of by the hardware. This needs
> some special awareness into existing interrupr injection path:
> 
> - for pending interrupt, instead of direct injection, we may need
>   update architecture specific indicators before resuming to guest.
> 
> - A pending interrupt, which is masked by ISR, should be also
>   considered in above update action, since hardware will decide
>   when to inject it at right time. Current has_interrupt and
>   get_interrupt only returns a valid vector from injection p.o.v.
> 
> Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>
> ---
>  arch/x86/include/asm/kvm_host.h |    5 +
>  arch/x86/include/asm/vmx.h      |   11 +++
>  arch/x86/kvm/irq.c              |   56 +++++++++++-
>  arch/x86/kvm/lapic.c            |   72 +++++++++------
>  arch/x86/kvm/lapic.h            |   23 +++++
>  arch/x86/kvm/svm.c              |   18 ++++
>  arch/x86/kvm/vmx.c              |  191 +++++++++++++++++++++++++++++++++++++--
>  arch/x86/kvm/x86.c              |   14 +++-
>  include/linux/kvm_host.h        |    3 +
>  virt/kvm/ioapic.c               |   18 ++++
>  virt/kvm/ioapic.h               |    4 +
>  virt/kvm/irq_comm.c             |   22 +++++
>  virt/kvm/kvm_main.c             |    5 +
>  13 files changed, 399 insertions(+), 43 deletions(-)
> 

>  static void recalculate_apic_map(struct kvm *kvm)
>  {
>  	struct kvm_apic_map *new, *old = NULL;
> @@ -236,12 +219,14 @@ static inline void kvm_apic_set_id(struct kvm_lapic *apic, u8 id)
>  {
>  	apic_set_reg(apic, APIC_ID, id << 24);
>  	recalculate_apic_map(apic->vcpu->kvm);
> +	ioapic_update_eoi_exitmap(apic->vcpu->kvm);
>  }

Move ioapic_update_eoi_exitmap into recalculate_apic_map.

>  static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
>  {
>  	apic_set_reg(apic, APIC_LDR, id);
>  	recalculate_apic_map(apic->vcpu->kvm);
> +	ioapic_update_eoi_exitmap(apic->vcpu->kvm);
>  }
>  

> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index b203ce7..990409a 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -434,6 +434,7 @@ struct vcpu_vmx {
>  	bool rdtscp_enabled;
>  
>  	bool virtual_x2apic_enabled;
> +	unsigned long eoi_exit_bitmap[4];

Use DECLARE_BITMAP (unsigned long is 4 bytes on 32-bit host).

>  	/* Support for a guest hypervisor (nested VMX) */
>  	struct nested_vmx nested;
> @@ -783,7 +784,8 @@ static inline bool cpu_has_vmx_apic_register_virt(void)
>  
>  static inline bool cpu_has_vmx_virtual_intr_delivery(void)
>  {
> -	return false;
> +	return vmcs_config.cpu_based_2nd_exec_ctrl &
> +		SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY;
>  }
>  
>  static inline bool cpu_has_vmx_flexpriority(void)
> @@ -2565,7 +2567,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
>  			SECONDARY_EXEC_PAUSE_LOOP_EXITING |
>  			SECONDARY_EXEC_RDTSCP |
>  			SECONDARY_EXEC_ENABLE_INVPCID |
> -			SECONDARY_EXEC_APIC_REGISTER_VIRT;
> +			SECONDARY_EXEC_APIC_REGISTER_VIRT |
> +			SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY;
>  		if (adjust_vmx_controls(min2, opt2,
>  					MSR_IA32_VMX_PROCBASED_CTLS2,
>  					&_cpu_based_2nd_exec_control) < 0)
> @@ -2579,7 +2582,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
>  
>  	if (!(_cpu_based_exec_control & CPU_BASED_TPR_SHADOW))
>  		_cpu_based_2nd_exec_control &= ~(
> -				SECONDARY_EXEC_APIC_REGISTER_VIRT);
> +				SECONDARY_EXEC_APIC_REGISTER_VIRT |
> +				SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY);

Nevermind the earlier comment about ().

> +static void set_eoi_exitmap_one(struct kvm_vcpu *vcpu,
> +				u32 vector)
> +{
> +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> +
> +	if (WARN_ONCE((vector > 255),
> +		"KVM VMX: vector (%d) out of range\n", vector))
> +		return;
> +	__set_bit(vector, vmx->eoi_exit_bitmap);
> +}
> +
> +void vmx_check_ioapic_entry(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq)
> +{
> +	struct kvm_lapic **dst;
> +	struct kvm_apic_map *map;
> +	unsigned long bitmap = 1;
> +	int i;
> +
> +	rcu_read_lock();
> +	map = rcu_dereference(vcpu->kvm->arch.apic_map);
> +
> +	if (unlikely(!map)) {
> +		set_eoi_exitmap_one(vcpu, irq->vector);
> +		goto out;
> +	}
> +
> +	if (irq->dest_mode == 0) { /* physical mode */
> +		if (irq->delivery_mode == APIC_DM_LOWEST ||
> +				irq->dest_id == 0xff) {
> +			set_eoi_exitmap_one(vcpu, irq->vector);
> +			goto out;
> +		}
> +		dst = &map->phys_map[irq->dest_id & 0xff];
> +	} else {
> +		u32 mda = irq->dest_id << (32 - map->ldr_bits);
> +
> +		dst = map->logical_map[apic_cluster_id(map, mda)];
> +
> +		bitmap = apic_logical_id(map, mda);
> +	}
> +
> +	for_each_set_bit(i, &bitmap, 16) {
> +		if (!dst[i])
> +			continue;
> +		if (dst[i]->vcpu == vcpu) {
> +			set_eoi_exitmap_one(vcpu, irq->vector);
> +			break;
> +		}
> +	}
> +
> +out:
> +	rcu_read_unlock();
> +}
> +
> +static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu)
> +{
> +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> +
> +	vmcs_write64(EOI_EXIT_BITMAP0, vmx->eoi_exit_bitmap[0]);
> +	vmcs_write64(EOI_EXIT_BITMAP1, vmx->eoi_exit_bitmap[1]);
> +	vmcs_write64(EOI_EXIT_BITMAP2, vmx->eoi_exit_bitmap[2]);
> +	vmcs_write64(EOI_EXIT_BITMAP3, vmx->eoi_exit_bitmap[3]);
> +}
> +
> +static void vmx_update_eoi_exitmap(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
> +	union kvm_ioapic_redirect_entry *e;
> +	struct kvm_lapic_irq irqe;
> +	int index;
> +	struct vcpu_vmx *vmx = to_vmx(vcpu);
> +
> +	/* clear eoi exit bitmap */
> +	memset(vmx->eoi_exit_bitmap, 0, 32);
> +
> +	/* traverse ioapic entry to set eoi exit bitmap*/
> +	for (index = 0; index < IOAPIC_NUM_PINS; index++) {
> +		e = &ioapic->redirtbl[index];
> +		if (!e->fields.mask &&
> +			(e->fields.trig_mode == IOAPIC_LEVEL_TRIG ||
> +			 kvm_irq_has_notifier(ioapic->kvm, KVM_IRQCHIP_IOAPIC,
> +				 index))) {
> +			irqe.dest_id = e->fields.dest_id;
> +			irqe.vector = e->fields.vector;
> +			irqe.dest_mode = e->fields.dest_mode;
> +			irqe.delivery_mode = e->fields.delivery_mode << 8;
> +			vmx_check_ioapic_entry(vcpu, &irqe);
> +
> +		}
> +	}
> +
> +	vmx_load_eoi_exitmap(vcpu);
> +}
> +
>  static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
>  {
>  	u32 exit_intr_info;
> @@ -7553,6 +7726,10 @@ static struct kvm_x86_ops vmx_x86_ops = {
>  	.update_cr8_intercept = update_cr8_intercept,
>  	.enable_virtual_x2apic_mode = vmx_enable_virtual_x2apic_mode,
>  	.disable_virtual_x2apic_mode = vmx_disable_virtual_x2apic_mode,
> +	.has_virtual_interrupt_delivery = vmx_has_virtual_interrupt_delivery,
> +	.update_apic_irq = vmx_update_apic_irq,
> +	.update_eoi_exitmap = vmx_update_eoi_exitmap,
> +	.set_svi = vmx_set_svi,
>  
>  	.set_tss_addr = vmx_set_tss_addr,
>  	.get_tdp_level = get_ept_level,
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 1c9c834..e6d8227 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5527,7 +5527,7 @@ static void inject_pending_event(struct kvm_vcpu *vcpu)
>  			vcpu->arch.nmi_injected = true;
>  			kvm_x86_ops->set_nmi(vcpu);
>  		}
> -	} else if (kvm_cpu_has_interrupt(vcpu)) {
> +	} else if (kvm_cpu_has_injectable_intr(vcpu)) {
>  		if (kvm_x86_ops->interrupt_allowed(vcpu)) {
>  			kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
>  					    false);
> @@ -5648,6 +5648,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
>  			kvm_handle_pmu_event(vcpu);
>  		if (kvm_check_request(KVM_REQ_PMI, vcpu))
>  			kvm_deliver_pmi(vcpu);
> +		if (kvm_check_request(KVM_REQ_EOIBITMAP, vcpu)) {
> +			mutex_lock(&vcpu->kvm->arch.vioapic->eoimap_lock);
> +			kvm_x86_ops->update_eoi_exitmap(vcpu);
> +			mutex_unlock(&vcpu->kvm->arch.vioapic->eoimap_lock);
> +		}

Take ioapic lock and irq_lock mutex.

> +void ioapic_update_eoi_exitmap(struct kvm *kvm)
> +{
> +#ifdef CONFIG_X86
> +	struct kvm_vcpu *vcpu = kvm->vcpus[0];
> +	struct kvm_ioapic *ioapic = kvm->arch.vioapic;
> +
> +	/* If vid is enabled in one of vcpus, then other
> +	 * vcpus also enabled it. */
> +	if (!kvm_apic_vid_enabled(vcpu) || !ioapic)
> +		return;

Is it even possible to call ioapic_update_eoi_exitmap() if 
kvm->arch.vioapic == NULL?

> +	kvm_make_update_eoibitmap_request(kvm);
> +#endif
> +}
> +
>  static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
>  {
>  	unsigned index;
> @@ -156,6 +170,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
>  		if (e->fields.trig_mode == IOAPIC_LEVEL_TRIG
>  		    && ioapic->irr & (1 << index))
>  			ioapic_service(ioapic, index);
> +		ioapic_update_eoi_exitmap(ioapic->kvm);
>  		break;
>  	}
>  }
> @@ -415,6 +430,9 @@ int kvm_ioapic_init(struct kvm *kvm)
>  	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, ioapic->base_address,
>  				      IOAPIC_MEM_LENGTH, &ioapic->dev);
>  	mutex_unlock(&kvm->slots_lock);
> +#ifdef CONFIG_X86
> +	mutex_init(&ioapic->eoimap_lock);
> +#endif
>  	if (ret < 0) {
>  		kvm->arch.vioapic = NULL;
>  		kfree(ioapic);
> diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
> index a30abfe..34544ce 100644
> --- a/virt/kvm/ioapic.h
> +++ b/virt/kvm/ioapic.h
> @@ -47,6 +47,9 @@ struct kvm_ioapic {
>  	void (*ack_notifier)(void *opaque, int irq);
>  	spinlock_t lock;
>  	DECLARE_BITMAP(handled_vectors, 256);
> +#ifdef CONFIG_X86
> +	struct mutex eoimap_lock;
> +#endif
>  };
>  
>  #ifdef DEBUG
> @@ -82,5 +85,6 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
>  		struct kvm_lapic_irq *irq);
>  int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
>  int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
> +void ioapic_update_eoi_exitmap(struct kvm *kvm);
>  
>  #endif
> diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
> index 656fa45..64aa1ab 100644
> --- a/virt/kvm/irq_comm.c
> +++ b/virt/kvm/irq_comm.c
> @@ -22,6 +22,7 @@
>  
>  #include <linux/kvm_host.h>
>  #include <linux/slab.h>
> +#include <linux/export.h>

Whats this for?

>  #include <trace/events/kvm.h>
>  
>  #include <asm/msidef.h>
> @@ -237,6 +238,25 @@ int kvm_set_irq_inatomic(struct kvm *kvm, int irq_source_id, u32 irq, int level)
>  	return ret;
>  }
>  
> +bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
> +{
> +	struct kvm_irq_ack_notifier *kian;
> +	struct hlist_node *n;
> +	int gsi;
> +
> +	rcu_read_lock();
> +	gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
> +	if (gsi != -1)
> +		hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
> +					 link)
> +			if (kian->gsi == gsi)
> +				return true;

Forgot rcu_read_unlock();

> +	rcu_read_unlock();
> +
> +	return false;
> +}
> +EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
> +
>  void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
>  {
>  	struct kvm_irq_ack_notifier *kian;
> @@ -261,6 +281,7 @@ void kvm_register_irq_ack_notifier(struct kvm *kvm,
>  	mutex_lock(&kvm->irq_lock);
>  	hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
>  	mutex_unlock(&kvm->irq_lock);
> +	ioapic_update_eoi_exitmap(kvm);
>  }

Move inside irq_lock protection.

>  
>  void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
> @@ -270,6 +291,7 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
>  	hlist_del_init_rcu(&kian->link);
>  	mutex_unlock(&kvm->irq_lock);
>  	synchronize_rcu();
> +	ioapic_update_eoi_exitmap(kvm);

Move both synchronize_rcu and ioapic_update_eoi_exitmap inside irq_lock
protection.
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