[PATCH v12 15/22] vfio: Introduce vfio_set_irqs_validate_and_prepare()

[Kirti Wankhede]

Vendor driver using mediated device framework would use same mechnism to
validate and prepare IRQs. Introducing this function to reduce code
replication in multiple drivers.

Signed-off-by: Kirti Wankhede <kwankhede@xxxxxxxxxx>
Signed-off-by: Neo Jia <cjia@xxxxxxxxxx>
Change-Id: Ie201f269dda0713ca18a07dc4852500bd8b48309
---
 drivers/vfio/vfio.c  | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/vfio.h |  4 ++++
 2 files changed, 52 insertions(+)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 3648fd74aa30..0afb58e26873 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1858,6 +1858,54 @@ int vfio_info_add_capability(struct vfio_info_cap *caps, int cap_type_id,
 }
 EXPORT_SYMBOL(vfio_info_add_capability);
 
+int vfio_set_irqs_validate_and_prepare(struct vfio_irq_set *hdr, int num_irqs,
+				       int max_irq_type, size_t *data_size)
+{
+	unsigned long minsz;
+	size_t size;
+
+	minsz = offsetofend(struct vfio_irq_set, count);
+
+	if ((hdr->argsz < minsz) || (hdr->index >= max_irq_type) ||
+	    (hdr->count >= (U32_MAX - hdr->start)) ||
+	    (hdr->flags & ~(VFIO_IRQ_SET_DATA_TYPE_MASK |
+				VFIO_IRQ_SET_ACTION_TYPE_MASK)))
+		return -EINVAL;
+
+	if (data_size)
+		*data_size = 0;
+
+	if (hdr->start >= num_irqs || hdr->start + hdr->count > num_irqs)
+		return -EINVAL;
+
+	switch (hdr->flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
+	case VFIO_IRQ_SET_DATA_NONE:
+		size = 0;
+		break;
+	case VFIO_IRQ_SET_DATA_BOOL:
+		size = sizeof(uint8_t);
+		break;
+	case VFIO_IRQ_SET_DATA_EVENTFD:
+		size = sizeof(int32_t);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (size) {
+		if (hdr->argsz - minsz < hdr->count * size)
+			return -EINVAL;
+
+		if (!data_size)
+			return -EINVAL;
+
+		*data_size = hdr->count * size;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(vfio_set_irqs_validate_and_prepare);
+
 /*
  * Pin a set of guest PFNs and return their associated host PFNs for local
  * domain only.
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index b1aaf69cb470..d4ce14d34ea9 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -114,6 +114,10 @@ extern void vfio_info_cap_shift(struct vfio_info_cap *caps, size_t offset);
 extern int vfio_info_add_capability(struct vfio_info_cap *caps,
 				    int cap_type_id, void *cap_type);
 
+extern int vfio_set_irqs_validate_and_prepare(struct vfio_irq_set *hdr,
+					      int num_irqs, int max_irq_type,
+					      size_t *data_size);
+
 struct pci_dev;
 #ifdef CONFIG_EEH
 extern void vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
-- 
2.7.0