[PATCH 1/4] VFIO: PLATFORM: Add device tree info API and skeleton

[PATCH 1/4] VFIO: PLATFORM: Add device tree info API and skeleton

[Antonios Motakis]

This patch introduced the API to return device tree info about
a PLATFORM device (if described by a device tree) and the skeleton
of the implementation for VFIO_PLATFORM. Information about any device
node bound by VFIO_PLATFORM should be queried via the introduced ioctl
VFIO_DEVICE_GET_DEVTREE_INFO.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
---
 drivers/vfio/platform/Makefile                |  2 +-
 drivers/vfio/platform/devtree.c               | 27 ++++++++++++++++++++++
 drivers/vfio/platform/vfio_platform.c         | 11 +++++++++
 drivers/vfio/platform/vfio_platform_private.h |  7 ++++++
 include/uapi/linux/vfio.h                     | 32 ++++++++++++++++++++++++---
 5 files changed, 75 insertions(+), 4 deletions(-)
 create mode 100644 drivers/vfio/platform/devtree.c

diff --git a/drivers/vfio/platform/Makefile b/drivers/vfio/platform/Makefile
index 2c53327..4313fd7 100644
--- a/drivers/vfio/platform/Makefile
+++ b/drivers/vfio/platform/Makefile
@@ -1,4 +1,4 @@
 
-vfio-platform-y := vfio_platform.o vfio_platform_irq.o
+vfio-platform-y := vfio_platform.o vfio_platform_irq.o devtree.o
 
 obj-$(CONFIG_VFIO_PLATFORM) += vfio-platform.o
diff --git a/drivers/vfio/platform/devtree.c b/drivers/vfio/platform/devtree.c
new file mode 100644
index 0000000..91cab88
--- /dev/null
+++ b/drivers/vfio/platform/devtree.c
@@ -0,0 +1,27 @@
+#include <linux/slab.h>
+#include <linux/vfio.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include "vfio_platform_private.h"
+
+void vfio_platform_devtree_get(struct vfio_platform_device *vdev)
+{
+	vdev->of_node = of_node_get(vdev->pdev->dev.of_node);
+}
+
+void vfio_platform_devtree_put(struct vfio_platform_device *vdev)
+{
+	of_node_put(vdev->of_node);
+	vdev->of_node = NULL;
+}
+
+bool vfio_platform_has_devtree(struct vfio_platform_device *vdev)
+{
+	return !!vdev->of_node;
+}
+
+long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
+				 unsigned long arg)
+{
+	return -EINVAL; /* not implemented yet */
+}
diff --git a/drivers/vfio/platform/vfio_platform.c b/drivers/vfio/platform/vfio_platform.c
index f4c06c6..e6fe05a 100644
--- a/drivers/vfio/platform/vfio_platform.c
+++ b/drivers/vfio/platform/vfio_platform.c
@@ -26,6 +26,7 @@
 #include <linux/vfio.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/of.h>
 #include <linux/irq.h>
 
 #include "vfio_platform_private.h"
@@ -66,6 +67,9 @@ static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
 
 	vdev->num_regions = cnt;
 
+	/* get device tree node for info if available */
+	vfio_platform_devtree_get(vdev);
+
 	return 0;
 err:
 	kfree(vdev->region);
@@ -74,6 +78,7 @@ err:
 
 static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
 {
+	vfio_platform_devtree_put(vdev);
 	vdev->num_regions = 0;
 	kfree(vdev->region);
 }
@@ -132,6 +137,9 @@ static long vfio_platform_ioctl(void *device_data,
 			return -EINVAL;
 
 		info.flags = VFIO_DEVICE_FLAGS_PLATFORM;
+		if (vfio_platform_has_devtree(vdev))
+			info.flags |= VFIO_DEVICE_FLAGS_DEVTREE;
+
 		info.num_regions = vdev->num_regions;
 		info.num_irqs = vdev->num_irqs;
 
@@ -210,6 +218,9 @@ static long vfio_platform_ioctl(void *device_data,
 
 		return ret;
 
+	} else if (cmd == VFIO_DEVICE_GET_DEVTREE_INFO) {
+		return vfio_platform_devtree_ioctl(vdev, arg);
+
 	} else if (cmd == VFIO_DEVICE_RESET)
 		return -EINVAL;
 
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index 86a9201..1c42ba0 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -49,6 +49,7 @@ struct vfio_platform_device {
 	u32				num_regions;
 	struct vfio_platform_irq	*irq;
 	u32				num_irqs;
+	struct device_node		*of_node;
 };
 
 extern int vfio_platform_irq_init(struct vfio_platform_device *vdev);
@@ -59,4 +60,10 @@ extern int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
 			uint32_t flags, unsigned index, unsigned start,
 			unsigned count, void *data);
 
+/* device tree info support in devtree.c */
+extern void vfio_platform_devtree_get(struct vfio_platform_device *vdev);
+extern void vfio_platform_devtree_put(struct vfio_platform_device *vdev);
+extern bool vfio_platform_has_devtree(struct vfio_platform_device *vdev);
+extern long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
+					unsigned long arg);
 #endif /* VFIO_PLATFORM_PRIVATE_H */
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index d381107..60f66ec 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -153,15 +153,41 @@ struct vfio_group_status {
 struct vfio_device_info {
 	__u32	argsz;
 	__u32	flags;
-#define VFIO_DEVICE_FLAGS_RESET	(1 << 0)	/* Device supports reset */
-#define VFIO_DEVICE_FLAGS_PCI	(1 << 1)	/* vfio-pci device */
-#define VFIO_DEVICE_FLAGS_PLATFORM (1 << 2)	/* vfio-platform device */
+#define VFIO_DEVICE_FLAGS_RESET		(1 << 0) /* Device supports reset */
+#define VFIO_DEVICE_FLAGS_PCI		(1 << 1) /* vfio-pci device */
+#define VFIO_DEVICE_FLAGS_PLATFORM	(1 << 2) /* vfio-platform device */
+#define VFIO_DEVICE_FLAGS_DEVTREE	(1 << 3) /* device tree metadata */
 	__u32	num_regions;	/* Max region index + 1 */
 	__u32	num_irqs;	/* Max IRQ index + 1 */
 };
 #define VFIO_DEVICE_GET_INFO		_IO(VFIO_TYPE, VFIO_BASE + 7)
 
 /**
+ * VFIO_DEVICE_GET_DEVTREE_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 16,
+ *						struct vfio_devtree_info)
+ *
+ * Retrieve information from the device's device tree, if available.
+ * Caller will initialize data[] with a single string with the requested
+ * devicetree property name, and type depending on whether a array of strings
+ * or an array of u32 values is expected. On success, data[] will be extended
+ * with the requested information, either as an array of u32, or with a list
+ * of strings sepparated by the NULL terminating character.
+ * Return: 0 on success, -errno on failure.
+ */
+struct vfio_devtree_info {
+	__u32	argsz;
+	__u32	type;
+#define VFIO_DEVTREE_PROP_NAMES		0
+#define VFIO_DEVTREE_ARR_TYPE_STRING	1
+#define VFIO_DEVTREE_ARR_TYPE_U8	2
+#define VFIO_DEVTREE_ARR_TYPE_U16	3
+#define VFIO_DEVTREE_ARR_TYPE_U32	4
+	__u32	length;
+	__u8	data[];
+};
+#define VFIO_DEVICE_GET_DEVTREE_INFO	_IO(VFIO_TYPE, VFIO_BASE + 17)
+
+/**
  * VFIO_DEVICE_GET_REGION_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 8,
  *				       struct vfio_region_info)
  *
-- 
1.8.3.2

[PATCH 2/4] VFIO: PLATFORM: DEVTREE: Return available property names

[Antonios Motakis]

For various reasons, the available properties of the platform device
node in the device tree node should be referred to by the property name.
Passing type = VFIO_DEVTREE_PROP_NAMES to VFIO_DEVICE_GET_DEVTREE_INFO,
returns a list of strings with the available properties that the VFIO
user can access.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
---
 drivers/vfio/platform/devtree.c | 68 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 67 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/platform/devtree.c b/drivers/vfio/platform/devtree.c
index 91cab88..b8fd4138 100644
--- a/drivers/vfio/platform/devtree.c
+++ b/drivers/vfio/platform/devtree.c
@@ -20,8 +20,74 @@ bool vfio_platform_has_devtree(struct vfio_platform_device *vdev)
 	return !!vdev->of_node;
 }
 
+static int devtree_get_prop_names(struct device_node *np, void __user *datap,
+				  unsigned long datasz, int *lenp)
+{
+	struct property *prop;
+	int len = 0, sz;
+	int ret = 0;
+
+	for_each_property_of_node(np, prop) {
+		sz = strlen(prop->name) + 1;
+
+		if (datasz < sz) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		if (copy_to_user(datap, prop->name, sz))
+			return -EFAULT;
+
+		datap += sz;
+		datasz -= sz;
+		len += sz;
+	}
+
+	/* if overflow occurs, calculate remaining length */
+	while (prop) {
+		len += strlen(prop->name) + 1;
+		prop = prop->next;
+	}
+
+	/* we expose the full_name in addition to the usual properties */
+	len += sz = strlen("full_name") + 1;
+	if (datasz < sz) {
+		ret = -EAGAIN;
+	} else if (copy_to_user(datap, "full_name", sz))
+		return -EFAULT;
+
+	*lenp = len;
+
+	return ret;
+}
+
 long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 				 unsigned long arg)
 {
-	return -EINVAL; /* not implemented yet */
+	struct vfio_devtree_info info;
+	unsigned long minsz = offsetofend(struct vfio_devtree_info, length);
+	void __user *datap = (void __user *) arg + minsz;
+	unsigned long int datasz;
+	int ret = -EINVAL;
+
+	if (!vfio_platform_has_devtree(vdev))
+		return -EINVAL;
+
+	if (copy_from_user(&info, (void __user *)arg, minsz))
+		return -EFAULT;
+
+	if (info.argsz < minsz)
+		return -EINVAL;
+
+	datasz = info.argsz - minsz;
+
+	if (info.type == VFIO_DEVTREE_PROP_NAMES) {
+		ret = devtree_get_prop_names(vdev->of_node, datap, datasz,
+								&info.length);
+	}
+
+	if (copy_to_user((void __user *)arg, &info, minsz))
+		ret = -EFAULT;
+
+	return ret;
 }
-- 
1.8.3.2

[PATCH 3/4] VFIO: PLATFORM: DEVTREE: Access property as a list of strings

[Antonios Motakis]

Certain device tree properties (e.g. the device node name, the compatible
string), are available as a list of strings (separated by the null
terminating character). Let the VFIO user query this type of properties.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
---
 drivers/vfio/platform/devtree.c | 60 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 60 insertions(+)

diff --git a/drivers/vfio/platform/devtree.c b/drivers/vfio/platform/devtree.c
index b8fd4138..80c60d4 100644
--- a/drivers/vfio/platform/devtree.c
+++ b/drivers/vfio/platform/devtree.c
@@ -61,6 +61,43 @@ static int devtree_get_prop_names(struct device_node *np, void __user *datap,
 	return ret;
 }
 
+static int devtree_get_strings(struct device_node *np, char *name,
+			       void __user *datap, unsigned long datasz)
+{
+	struct property *prop;
+	int len;
+
+	prop = of_find_property(np, name, &len);
+
+	if (!prop)
+		return -EINVAL;
+
+	if (len > datasz)
+		return -EAGAIN;
+
+	if (copy_to_user(datap, prop->value, len))
+		return -EFAULT;
+	else
+		return 0;
+}
+
+static int devtree_get_full_name(struct device_node *np, void __user *datap,
+				 unsigned long datasz, int *lenp)
+{
+	int len = strlen(np->full_name) + 1;
+
+	if (lenp)
+		*lenp = len;
+
+	if (len > datasz)
+		return -EAGAIN;
+
+	if (copy_to_user(datap, np->full_name, len))
+		return -EFAULT;
+
+	return 0;
+}
+
 long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 				 unsigned long arg)
 {
@@ -68,6 +105,7 @@ long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 	unsigned long minsz = offsetofend(struct vfio_devtree_info, length);
 	void __user *datap = (void __user *) arg + minsz;
 	unsigned long int datasz;
+	char *name;
 	int ret = -EINVAL;
 
 	if (!vfio_platform_has_devtree(vdev))
@@ -84,8 +122,30 @@ long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 	if (info.type == VFIO_DEVTREE_PROP_NAMES) {
 		ret = devtree_get_prop_names(vdev->of_node, datap, datasz,
 								&info.length);
+		goto out;
 	}
 
+	name = kzalloc(datasz, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+	if (copy_from_user(name, datap, datasz))
+		return -EFAULT;
+
+	if (!of_find_property(vdev->of_node, name, &info.length)) {
+		/* special case full_name as a property that is not on the fdt,
+		 * but we wish to return to the user as it includes the full
+		 * path of the device */
+		if (!strcmp(name, "full_name") &&
+				(info.type == VFIO_DEVTREE_ARR_TYPE_STRING))
+			ret = devtree_get_full_name(vdev->of_node, datap,
+						    datasz, &info.length);
+
+	} else if (info.type == VFIO_DEVTREE_ARR_TYPE_STRING)
+		ret = devtree_get_strings(vdev->of_node, name, datap, datasz);
+
+	kfree(name);
+
+out:
 	if (copy_to_user((void __user *)arg, &info, minsz))
 		ret = -EFAULT;
 
-- 
1.8.3.2

[PATCH 4/4] VFIO: PLATFORM: DEVTREE: Return arrays of u32, u16, or u8

[Antonios Motakis]

Certain properties of a device tree node are accessible as an array
of unsigned integers, either u32, u16, or u8. Let the VFIO user query
this type of device node properties.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
---
 drivers/vfio/platform/devtree.c | 99 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

diff --git a/drivers/vfio/platform/devtree.c b/drivers/vfio/platform/devtree.c
index 80c60d4..331cc34 100644
--- a/drivers/vfio/platform/devtree.c
+++ b/drivers/vfio/platform/devtree.c
@@ -98,6 +98,96 @@ static int devtree_get_full_name(struct device_node *np, void __user *datap,
 	return 0;
 }
 
+static int devtree_get_u32_arr(const struct device_node *np, const char *name,
+			       void __user *datap, unsigned long datasz)
+{
+	int ret;
+	int n;
+	u32 *out;
+
+	n = of_property_count_elems_of_size(np, name, sizeof(u32));
+	if (n < 0)
+		return n;
+
+	if (n * sizeof(u32) > datasz)
+		return -EAGAIN;
+
+	out = kcalloc(n, sizeof(u32), GFP_KERNEL);
+	if (!out)
+		return -EFAULT;
+
+	ret = of_property_read_u32_array(np, name, out, n);
+	if (ret)
+		goto out;
+
+	if (copy_to_user(datap, out, n * sizeof(u32)))
+		ret = -EFAULT;
+
+out:
+	kfree(out);
+	return ret;
+}
+
+static int devtree_get_u16_arr(const struct device_node *np, const char *name,
+			       void __user *datap, unsigned long datasz)
+{
+	int ret;
+	int n;
+	u16 *out;
+
+	n = of_property_count_elems_of_size(np, name, sizeof(u16));
+	if (n < 0)
+		return n;
+
+	if (n * sizeof(u16) > datasz)
+		return -EAGAIN;
+
+	out = kcalloc(n, sizeof(u16), GFP_KERNEL);
+	if (!out)
+		return -EFAULT;
+
+	ret = of_property_read_u16_array(np, name, out, n);
+	if (ret)
+		goto out;
+
+	if (copy_to_user(datap, out, n * sizeof(u16)))
+		ret = -EFAULT;
+
+out:
+	kfree(out);
+	return ret;
+}
+
+static int devtree_get_u8_arr(const struct device_node *np, const char *name,
+			       void __user *datap, unsigned long datasz)
+{
+	int ret;
+	int n;
+	u8 *out;
+
+	n = of_property_count_elems_of_size(np, name, sizeof(u8));
+	if (n < 0)
+		return n;
+
+	if (n * sizeof(u8) > datasz)
+		return -EAGAIN;
+
+	out = kcalloc(n, sizeof(u8), GFP_KERNEL);
+	if (!out)
+		return -EFAULT;
+
+	ret = of_property_read_u8_array(np, name, out, n);
+	if (ret)
+		goto out;
+
+	if (copy_to_user(datap, out, n * sizeof(u8)))
+		ret = -EFAULT;
+
+out:
+	kfree(out);
+	return ret;
+}
+
 long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 				 unsigned long arg)
 {
@@ -143,6 +233,15 @@ long vfio_platform_devtree_ioctl(struct vfio_platform_device *vdev,
 	} else if (info.type == VFIO_DEVTREE_ARR_TYPE_STRING)
 		ret = devtree_get_strings(vdev->of_node, name, datap, datasz);
 
+	else if (info.type == VFIO_DEVTREE_ARR_TYPE_U32)
+		ret = devtree_get_u32_arr(vdev->of_node, name, datap, datasz);
+
+	else if (info.type == VFIO_DEVTREE_ARR_TYPE_U16)
+		ret = devtree_get_u16_arr(vdev->of_node, name, datap, datasz);
+
+	else if (info.type == VFIO_DEVTREE_ARR_TYPE_U8)
+		ret = devtree_get_u8_arr(vdev->of_node, name, datap, datasz);
+
 	kfree(name);
 
 out:
-- 
1.8.3.2