linux-kernel - [PATCH v2 1/8] VFIO: platform: Differentiate auto-masking from user masking

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Message-Id: <1497531160-29162-2-git-send-email-eric.auger@redhat.com>
Date:   Thu, 15 Jun 2017 14:52:33 +0200
From:   Eric Auger <eric.auger@...hat.com>
To:     eric.auger.pro@...il.com, eric.auger@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        kvmarm@...ts.cs.columbia.edu, alex.williamson@...hat.com,
        b.reynal@...tualopensystems.com, pbonzini@...hat.com,
        marc.zyngier@....com, christoffer.dall@...aro.org
Cc:     drjones@...hat.com, wei@...hat.com
Subject: [PATCH v2 1/8] VFIO: platform: Differentiate auto-masking from user masking

For direct EOI modality we will need to differentiate a userspace
masking from the IRQ handler auto-masking.

The level sensitive IRQ handler sets the automasked flag while
VFIO_DEVICE_SET_IRQS with VFIO_IRQ_SET_ACTION_MASK sets the
usermasked flag. VFIO_IRQ_SET_ACTION_UNMASK resets both flags.

Signed-off-by: Eric Auger <eric.auger@...hat.com>

---

v1 -> v2:
- rename maked into usermasked
- add is_masked() macro
- commit message reworded to better explain role of each flag
- change commit title
---
 drivers/vfio/platform/vfio_platform_irq.c     | 18 ++++++++++--------
 drivers/vfio/platform/vfio_platform_private.h |  6 +++++-
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 46d4750..6740dbe 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -29,9 +29,9 @@ static void vfio_platform_mask(struct vfio_platform_irq *irq_ctx)
 
 	spin_lock_irqsave(&irq_ctx->lock, flags);
 
-	if (!irq_ctx->masked) {
+	if (!is_masked(irq_ctx)) {
 		disable_irq_nosync(irq_ctx->hwirq);
-		irq_ctx->masked = true;
+		irq_ctx->usermasked = true;
 	}
 
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
@@ -89,9 +89,10 @@ static void vfio_platform_unmask(struct vfio_platform_irq *irq_ctx)
 
 	spin_lock_irqsave(&irq_ctx->lock, flags);
 
-	if (irq_ctx->masked) {
+	if (is_masked(irq_ctx)) {
 		enable_irq(irq_ctx->hwirq);
-		irq_ctx->masked = false;
+		irq_ctx->usermasked = false;
+		irq_ctx->automasked = false;
 	}
 
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
@@ -152,12 +153,12 @@ static irqreturn_t vfio_automasked_irq_handler(int irq, void *dev_id)
 
 	spin_lock_irqsave(&irq_ctx->lock, flags);
 
-	if (!irq_ctx->masked) {
+	if (!is_masked(irq_ctx)) {
 		ret = IRQ_HANDLED;
 
 		/* automask maskable interrupts */
 		disable_irq_nosync(irq_ctx->hwirq);
-		irq_ctx->masked = true;
+		irq_ctx->automasked = true;
 	}
 
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
@@ -217,7 +218,7 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
 		return ret;
 	}
 
-	if (!irq->masked)
+	if (!irq->usermasked)
 		enable_irq(irq->hwirq);
 
 	return 0;
@@ -314,7 +315,8 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
 
 		vdev->irqs[i].count = 1;
 		vdev->irqs[i].hwirq = hwirq;
-		vdev->irqs[i].masked = false;
+		vdev->irqs[i].usermasked = false;
+		vdev->irqs[i].automasked = false;
 	}
 
 	vdev->num_irqs = cnt;
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 85ffe5d..e8db291 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -33,7 +33,8 @@ struct vfio_platform_irq {
 	int			hwirq;
 	char			*name;
 	struct eventfd_ctx	*trigger;
-	bool			masked;
+	bool			usermasked;
+	bool			automasked;
 	spinlock_t		lock;
 	struct virqfd		*unmask;
 	struct virqfd		*mask;
@@ -102,6 +103,9 @@ extern int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 extern void __vfio_platform_register_reset(struct vfio_platform_reset_node *n);
 extern void vfio_platform_unregister_reset(const char *compat,
 					   vfio_platform_reset_fn_t fn);
+
+#define is_masked(irq) ((irq)->usermasked || (irq)->automasked)
+
 #define vfio_platform_register_reset(__compat, __reset)		\
 static struct vfio_platform_reset_node __reset ## _node = {	\
 	.owner = THIS_MODULE,					\
-- 
2.5.5