linux-kernel - [PATCHv7 26/26] vfio/platform: implement IRQ masking/unmasking via an eventfd

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Message-Id: <1411483586-29304-27-git-send-email-a.motakis@virtualopensystems.com>
Date:	Tue, 23 Sep 2014 16:46:25 +0200
From:	Antonios Motakis <a.motakis@...tualopensystems.com>
To:	alex.williamson@...hat.com, kvmarm@...ts.cs.columbia.edu,
	iommu@...ts.linux-foundation.org
Cc:	tech@...tualopensystems.com, kvm@...r.kernel.org,
	christoffer.dall@...aro.org, will.deacon@....com,
	kim.phillips@...escale.com, eric.auger@...aro.org,
	marc.zyngier@....com,
	Antonios Motakis <a.motakis@...tualopensystems.com>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCHv7 26/26] vfio/platform: implement IRQ masking/unmasking via an eventfd

With this patch the VFIO user will be able to set an eventfd that can be
used in order to mask and unmask IRQs of platform devices.

Signed-off-by: Antonios Motakis <a.motakis@...tualopensystems.com>
---
 drivers/vfio/platform/vfio_platform_irq.c     | 48 +++++++++++++++++++++++++--
 drivers/vfio/platform/vfio_platform_private.h |  2 ++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
index 90fa25a..4ea3d5a 100644
--- a/drivers/vfio/platform/vfio_platform_irq.c
+++ b/drivers/vfio/platform/vfio_platform_irq.c
@@ -45,11 +45,21 @@ static void vfio_platform_mask(struct vfio_platform_irq *irq_ctx)
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
 }
 
+static int vfio_platform_mask_handler(void *opaque, void *unused)
+{
+	struct vfio_platform_irq *irq_ctx = opaque;
+
+	vfio_platform_mask(irq_ctx);
+
+	return 0;
+}
+
 static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
 				    unsigned index, unsigned start,
 				    unsigned count, uint32_t flags, void *data)
 {
 	uint8_t irq_bitmap;
+	int32_t fd;
 
 	if (start != 0 || count != 1)
 		return -EINVAL;
@@ -75,7 +85,19 @@ static int vfio_platform_set_irq_mask(struct vfio_platform_device *vdev,
 		vfio_platform_mask(&vdev->irqs[index]);
 		return 0;
 
-	case VFIO_IRQ_SET_DATA_EVENTFD: /* XXX not implemented yet */
+	case VFIO_IRQ_SET_DATA_EVENTFD:
+		if (copy_from_user(&fd, data, sizeof(int32_t)))
+			return -EFAULT;
+
+		if (fd >= 0)
+			return virqfd_enable((void *) &vdev->irqs[index],
+					     vfio_platform_mask_handler,
+					     NULL, NULL,
+					     &vdev->irqs[index].mask, fd);
+
+		virqfd_disable(&vdev->irqs[index].mask);
+		return 0;
+
 	default:
 		return -ENOTTY;
 	}
@@ -97,11 +119,21 @@ static void vfio_platform_unmask(struct vfio_platform_irq *irq_ctx)
 	spin_unlock_irqrestore(&irq_ctx->lock, flags);
 }
 
+static int vfio_platform_unmask_handler(void *opaque, void *unused)
+{
+	struct vfio_platform_irq *irq_ctx = opaque;
+
+	vfio_platform_unmask(irq_ctx);
+
+	return 0;
+}
+
 static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
 				    unsigned index, unsigned start,
 				    unsigned count, uint32_t flags, void *data)
 {
 	uint8_t irq_bitmap;
+	int32_t fd;
 
 	if (start != 0 || count != 1)
 		return -EINVAL;
@@ -123,7 +155,19 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
 		vfio_platform_unmask(&vdev->irqs[index]);
 		return 0;
 
-	case VFIO_IRQ_SET_DATA_EVENTFD: /* XXX not implemented yet */
+	case VFIO_IRQ_SET_DATA_EVENTFD:
+		if (copy_from_user(&fd, data, sizeof(int32_t)))
+			return -EFAULT;
+
+		if (fd >= 0)
+			return virqfd_enable((void *) &vdev->irqs[index],
+					     vfio_platform_unmask_handler,
+					     NULL, NULL,
+					     &vdev->irqs[index].unmask, fd);
+
+		virqfd_disable(&vdev->irqs[index].unmask);
+		return 0;
+
 	default:
 		return -ENOTTY;
 	}
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 500e299..dd1beda 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -32,6 +32,8 @@ struct vfio_platform_irq {
 	struct eventfd_ctx	*trigger;
 	bool			masked;
 	spinlock_t		lock;
+	struct virqfd		*unmask;
+	struct virqfd		*mask;
 };
 
 struct vfio_platform_region {
-- 
1.8.3.2

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