diff mbox

[v3,16/55] KVM: arm/arm64: vgic-new: Add IRQ sorting

Message ID 1462531568-9799-17-git-send-email-andre.przywara@arm.com
State Superseded
Headers show

Commit Message

Andre Przywara May 6, 2016, 10:45 a.m. UTC
From: Christoffer Dall <christoffer.dall@linaro.org>


Adds the sorting function to cover the case where you have more IRQs
to consider than you have LRs. We now consider priorities.

Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

---
 virt/kvm/arm/vgic/vgic.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)

-- 
2.7.3


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Comments

Auger Eric May 10, 2016, 9:29 a.m. UTC | #1
On 05/06/2016 12:45 PM, Andre Przywara wrote:
> From: Christoffer Dall <christoffer.dall@linaro.org>

> 

> Adds the sorting function to cover the case where you have more IRQs

> to consider than you have LRs. We now consider priorities.

> 

> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

> Signed-off-by: Andre Przywara <andre.przywara@arm.com>

> ---

>  virt/kvm/arm/vgic/vgic.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++

>  1 file changed, 57 insertions(+)

> 

> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c

> index 92b78a0..4fb20fd 100644

> --- a/virt/kvm/arm/vgic/vgic.c

> +++ b/virt/kvm/arm/vgic/vgic.c

> @@ -16,6 +16,7 @@

>  

>  #include <linux/kvm.h>

>  #include <linux/kvm_host.h>

> +#include <linux/list_sort.h>

>  

>  #include "vgic.h"

>  

> @@ -96,6 +97,62 @@ static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)

>  }

>  

>  /*

> + * The order of items in the ap_lists defines how we'll pack things in LRs as

> + * well, the first items in the list being the first things populated in the

> + * LRs.

> + *

> + * A hard rule is that active interrupts can never be pushed out of the LRs

> + * (and therefore take priority) since we cannot reliably trap on deactivation

> + * of IRQs and therefore they have to be present in the LRs.

> + *

> + * Otherwise things should be sorted by the priority field and the GIC

> + * hardware support will take care of preemption of priority groups etc.

> + *

> + * Return negative if "a" sorts before "b", 0 to preserve order, and positive

> + * to sort "b" before "a".

> + */

> +static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)

> +{

> +	struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);

> +	struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);

> +	bool penda, pendb;

> +	int ret;

> +

> +	spin_lock(&irqa->irq_lock);

> +	spin_lock(&irqb->irq_lock);

> +

> +	if (irqa->active || irqb->active) {

> +		ret = (int)irqb->active - (int)irqa->active;

> +		goto out;

> +	}

> +

> +	penda = irqa->enabled && irqa->pending;

> +	pendb = irqb->enabled && irqb->pending;

> +

> +	if (!penda || !pendb) {

> +		ret = (int)pendb - (int)penda;

> +		goto out;

> +	}

> +

> +	/* Both pending and enabled, sort by priority */

> +	ret = irqa->priority - irqb->priority;

> +out:

> +	spin_unlock(&irqb->irq_lock);

> +	spin_unlock(&irqa->irq_lock);

> +	return ret;

> +}

> +

> +/* Must be called with the ap_list_lock held */

> +static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)

> +{

> +	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;

> +

> +	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));

> +

> +	list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);

> +}

> +

> +/*

>   * Only valid injection if changing level for level-triggered IRQs or for a

>   * rising edge.

>   */

> 

Reviewed-by: Eric Auger <eric.auger@linaro.org>


Eric


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diff mbox

Patch

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 92b78a0..4fb20fd 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -16,6 +16,7 @@ 
 
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
+#include <linux/list_sort.h>
 
 #include "vgic.h"
 
@@ -96,6 +97,62 @@  static struct kvm_vcpu *vgic_target_oracle(struct vgic_irq *irq)
 }
 
 /*
+ * The order of items in the ap_lists defines how we'll pack things in LRs as
+ * well, the first items in the list being the first things populated in the
+ * LRs.
+ *
+ * A hard rule is that active interrupts can never be pushed out of the LRs
+ * (and therefore take priority) since we cannot reliably trap on deactivation
+ * of IRQs and therefore they have to be present in the LRs.
+ *
+ * Otherwise things should be sorted by the priority field and the GIC
+ * hardware support will take care of preemption of priority groups etc.
+ *
+ * Return negative if "a" sorts before "b", 0 to preserve order, and positive
+ * to sort "b" before "a".
+ */
+static int vgic_irq_cmp(void *priv, struct list_head *a, struct list_head *b)
+{
+	struct vgic_irq *irqa = container_of(a, struct vgic_irq, ap_list);
+	struct vgic_irq *irqb = container_of(b, struct vgic_irq, ap_list);
+	bool penda, pendb;
+	int ret;
+
+	spin_lock(&irqa->irq_lock);
+	spin_lock(&irqb->irq_lock);
+
+	if (irqa->active || irqb->active) {
+		ret = (int)irqb->active - (int)irqa->active;
+		goto out;
+	}
+
+	penda = irqa->enabled && irqa->pending;
+	pendb = irqb->enabled && irqb->pending;
+
+	if (!penda || !pendb) {
+		ret = (int)pendb - (int)penda;
+		goto out;
+	}
+
+	/* Both pending and enabled, sort by priority */
+	ret = irqa->priority - irqb->priority;
+out:
+	spin_unlock(&irqb->irq_lock);
+	spin_unlock(&irqa->irq_lock);
+	return ret;
+}
+
+/* Must be called with the ap_list_lock held */
+static void vgic_sort_ap_list(struct kvm_vcpu *vcpu)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+	DEBUG_SPINLOCK_BUG_ON(!spin_is_locked(&vgic_cpu->ap_list_lock));
+
+	list_sort(NULL, &vgic_cpu->ap_list_head, vgic_irq_cmp);
+}
+
+/*
  * Only valid injection if changing level for level-triggered IRQs or for a
  * rising edge.
  */