linux-kernel - [RFC v2 7/9] VFIO: platform: add irq bypass producer management

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Date:	Mon,  6 Jul 2015 15:24:41 +0200
From:	Eric Auger <eric.auger@...aro.org>
To:	eric.auger@...com, eric.auger@...aro.org,
	linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
	kvm@...r.kernel.org, christoffer.dall@...aro.org,
	marc.zyngier@....com, avi.kivity@...il.com, mtosatti@...hat.com,
	feng.wu@...el.com, joro@...tes.org, b.reynal@...tualopensystems.com
Cc:	linux-kernel@...r.kernel.org, patches@...aro.org,
	alex.williamson@...hat.com, pbonzini@...hat.com
Subject: [RFC v2 7/9] VFIO: platform: add irq bypass producer management

This patch populates the IRQ bypass callacks:
- stop/resume producer simply consist in disabling/enabling the host irq
- add/del consumer: basically set the automasked flag to false/true
- update remains void

Signed-off-by: Eric Auger <eric.auger@...aro.org>

---

v1 -> v2:
- device handle caching in vfio_platform_device is introduced in a
  separate patch
- use container_of
---
 drivers/vfio/platform/vfio_platform_irq.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index d00ed24..7dc17a6 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -222,22 +222,49 @@ static int vfio_platform_is_active(struct vfio_platform_irq *irq)
 
 static void vfio_platform_irq_bypass_stop(struct irq_bypass_producer *prod)
 {
+	disable_irq(prod->irq);
 }
 
 static void vfio_platform_irq_bypass_resume(struct irq_bypass_producer *prod)
 {
+	enable_irq(prod->irq);
 }
 
 static void vfio_platform_irq_bypass_add_consumer(
 			struct irq_bypass_producer *prod,
 			struct irq_bypass_consumer *cons)
 {
+	int ret;
+	struct vfio_platform_irq *irq =
+		container_of(prod, struct vfio_platform_irq, producer);
+
+	//TODO
+	/*
+	 * if the IRQ is active at irqchip level or VFIO (auto)masked
+	 * this means the host IRQ is already under injection in the
+	 * guest and this not safe to change the forwarding state at
+	 * that stage.
+	 * It is not possible to differentiate user-space masking
+	 * from auto-masking, leading to possible false detection of
+	 * active state.
+	 */
+	prod->active = vfio_platform_is_active(irq);
+
+	ret = vfio_platform_set_automasked(irq, false);
+	WARN_ON(ret);
 }
 
 static void vfio_platform_irq_bypass_del_consumer(
 			struct irq_bypass_producer *prod,
 			struct irq_bypass_consumer *cons)
 {
+	struct vfio_platform_irq *irq =
+		container_of(prod, struct vfio_platform_irq, producer);
+
+	if (prod->active)
+		vfio_platform_mask(irq);
+
+	vfio_platform_set_automasked(irq, true);
 }
 
 static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
-- 
1.9.1

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