vfio fsl-mc: Return fsl-mc device MMIO region info

Add support for VFIO_DEVICE_GET_REGION_INFO ioctl call.
This allows usespace to know device mmap-able region details.

MC device (DPIO) have a region which is cacheable and
non-shareable. Describe these regions as cacheable
so that during mmap() they will be mapped accordingly.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>

2 files changed, 113 insertions, 1 deletions

diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
index b01e9c0..e5a6779 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
@@ -28,16 +28,90 @@
 #define DRIVER_AUTHOR	"Bharat Bhushan <bharat.bhushan@nxp.com>"
 #define DRIVER_DESC	"VFIO for FSL-MC devices - User Level meta-driver"
 
+static DEFINE_MUTEX(driver_lock);
+
+/* FSl-MC device regions (address and size) are aligned to 64K.
+ * While MC firmware reports size less than 64K for some objects (it actually
+ * reports size which does not include reserved space beyond valid bytes).
+ * Align the size to PAGE_SIZE for userspace to mmap.
+ */
+static size_t aligned_region_size(struct fsl_mc_device *mc_dev, int index)
+{
+	size_t size;
+
+	size = resource_size(&mc_dev->regions[index]);
+	return PAGE_ALIGN(size);
+}
+
+static int vfio_fsl_mc_regions_init(struct vfio_fsl_mc_device *vdev)
+{
+	struct fsl_mc_device *mc_dev = vdev->mc_dev;
+	int count = mc_dev->obj_desc.region_count;
+	int i;
+
+	vdev->regions = kcalloc(count, sizeof(struct vfio_fsl_mc_region),
+				GFP_KERNEL);
+	if (!vdev->regions)
+		return -ENOMEM;
+
+	for (i = 0; i < mc_dev->obj_desc.region_count; i++) {
+		vdev->regions[i].addr = mc_dev->regions[i].start;
+		vdev->regions[i].size = aligned_region_size(mc_dev, i);
+		vdev->regions[i].type = VFIO_FSL_MC_REGION_TYPE_MMIO;
+		if (mc_dev->regions[i].flags & IORESOURCE_CACHEABLE)
+			vdev->regions[i].type |=
+					VFIO_FSL_MC_REGION_TYPE_CACHEABLE;
+		vdev->regions[i].flags = 0;
+	}
+
+	vdev->num_regions = mc_dev->obj_desc.region_count;
+	return 0;
+}
+
+static void vfio_fsl_mc_regions_cleanup(struct vfio_fsl_mc_device *vdev)
+{
+	vdev->num_regions = 0;
+	kfree(vdev->regions);
+}
+
 static int vfio_fsl_mc_open(void *device_data)
 {
+	struct vfio_fsl_mc_device *vdev = device_data;
+	int ret;
+
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
+	mutex_lock(&driver_lock);
+	if (!vdev->refcnt) {
+		ret = vfio_fsl_mc_regions_init(vdev);
+		if (ret)
+			goto error_region_init;
+	}
+
+	vdev->refcnt++;
+	mutex_unlock(&driver_lock);
 	return 0;
+
+error_region_init:
+	mutex_unlock(&driver_lock);
+	if (ret)
+		module_put(THIS_MODULE);
+
+	return ret;
 }
 
 static void vfio_fsl_mc_release(void *device_data)
 {
+	struct vfio_fsl_mc_device *vdev = device_data;
+
+	mutex_lock(&driver_lock);
+
+	if (!(--vdev->refcnt))
+		vfio_fsl_mc_regions_cleanup(vdev);
+
+	mutex_unlock(&driver_lock);
+
 	module_put(THIS_MODULE);
 }
 
@@ -72,7 +146,25 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 	}
 	case VFIO_DEVICE_GET_REGION_INFO:
 	{
-		return -EINVAL;
+		struct vfio_region_info info;
+
+		minsz = offsetofend(struct vfio_region_info, offset);
+
+		if (copy_from_user(&info, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (info.argsz < minsz)
+			return -EINVAL;
+
+		if (info.index >= vdev->num_regions)
+			return -EINVAL;
+
+		/* map offset to the physical address  */
+		info.offset = VFIO_FSL_MC_INDEX_TO_OFFSET(info.index);
+		info.size = vdev->regions[info.index].size;
+		info.flags = vdev->regions[info.index].flags;
+
+		return copy_to_user((void __user *)arg, &info, minsz);
 	}
 	case VFIO_DEVICE_GET_IRQ_INFO:
 	{
diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
index e680f8e..e9d7f3b 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
@@ -13,8 +13,28 @@
 #ifndef VFIO_FSL_MC_PRIVATE_H
 #define VFIO_FSL_MC_PRIVATE_H
 
+#define VFIO_FSL_MC_OFFSET_SHIFT    40
+#define VFIO_FSL_MC_OFFSET_MASK (((u64)(1) << VFIO_FSL_MC_OFFSET_SHIFT) - 1)
+
+#define VFIO_FSL_MC_OFFSET_TO_INDEX(off) (off >> VFIO_FSL_MC_OFFSET_SHIFT)
+
+#define VFIO_FSL_MC_INDEX_TO_OFFSET(index)	\
+	((u64)(index) << VFIO_FSL_MC_OFFSET_SHIFT)
+
+struct vfio_fsl_mc_region {
+	u32			flags;
+#define VFIO_FSL_MC_REGION_TYPE_MMIO  1
+#define VFIO_FSL_MC_REGION_TYPE_CACHEABLE  2
+	u32			type;
+	u64			addr;
+	resource_size_t		size;
+};
+
 struct vfio_fsl_mc_device {
 	struct fsl_mc_device		*mc_dev;
+	int				refcnt;
+	u32				num_regions;
+	struct vfio_fsl_mc_region	*regions;
 };
 
 #endif /* VFIO_PCI_PRIVATE_H */