Intel MIC Host Driver Changes for Virtio Devices.

This patch introduces the host "Virtio over PCIe" interface for
Intel MIC. It allows creating user space backends on the host and instantiating
virtio devices for them on the Intel MIC card. It uses the existing VRINGH
infrastructure in the kernel to access virtio rings from the host. A character
device per MIC is exposed with IOCTL, mmap and poll callbacks. This allows the
user space backend to:
(a) add/remove a virtio device via a device page.
(b) map (R/O) virtio rings and device page to user space.
(c) poll for availability of data.
(d) copy a descriptor or entire descriptor chain to/from the card.
(e) modify virtio configuration.
(f) handle virtio device reset.
The buffers are copied over using CPU copies for this initial patch
and host initiated MIC DMA support is planned for future patches.
The avail and desc virtio rings are in host memory and the used ring
is in card memory to maximize writes across PCIe for performance.

Co-author: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Caz Yokoyama <Caz.Yokoyama@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Signed-off-by: Harshavardhan R Kharche <harshavardhan.r.kharche@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Acked-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Reviewed-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/misc/mic/host/mic_main.c b/drivers/misc/mic/host/mic_main.c
index 998a20ab7e96..a8965d496e84 100644
--- a/drivers/misc/mic/host/mic_main.c
+++ b/drivers/misc/mic/host/mic_main.c
@@ -25,12 +25,15 @@
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/poll.h>
 
 #include <linux/mic_common.h>
 #include "../common/mic_device.h"
 #include "mic_device.h"
 #include "mic_x100.h"
 #include "mic_smpt.h"
+#include "mic_fops.h"
+#include "mic_virtio.h"
 
 static const char mic_driver_name[] = "mic";
 
@@ -64,6 +67,15 @@ static struct class *g_mic_class;
 /* Base device node number for MIC devices */
 static dev_t g_mic_devno;
 
+static const struct file_operations mic_fops = {
+	.open = mic_open,
+	.release = mic_release,
+	.unlocked_ioctl = mic_ioctl,
+	.poll = mic_poll,
+	.mmap = mic_mmap,
+	.owner = THIS_MODULE,
+};
+
 /* Initialize the device page */
 static int mic_dp_init(struct mic_device *mdev)
 {
@@ -193,6 +205,7 @@ mic_device_init(struct mic_device *mdev, struct pci_dev *pdev)
 	mdev->irq_info.next_avail_src = 0;
 	INIT_WORK(&mdev->reset_trigger_work, mic_reset_trigger_work);
 	INIT_WORK(&mdev->shutdown_work, mic_shutdown_work);
+	INIT_LIST_HEAD(&mdev->vdev_list);
 }
 
 /**
@@ -330,7 +343,19 @@ static int mic_probe(struct pci_dev *pdev,
 	mic_bootparam_init(mdev);
 
 	mic_create_debug_dir(mdev);
+	cdev_init(&mdev->cdev, &mic_fops);
+	mdev->cdev.owner = THIS_MODULE;
+	rc = cdev_add(&mdev->cdev, MKDEV(MAJOR(g_mic_devno), mdev->id), 1);
+	if (rc) {
+		dev_err(&pdev->dev, "cdev_add err id %d rc %d\n", mdev->id, rc);
+		goto cleanup_debug_dir;
+	}
 	return 0;
+cleanup_debug_dir:
+	mic_delete_debug_dir(mdev);
+	mutex_lock(&mdev->mic_mutex);
+	mic_free_irq(mdev, mdev->shutdown_cookie, mdev);
+	mutex_unlock(&mdev->mic_mutex);
 dp_uninit:
 	mic_dp_uninit(mdev);
 sysfs_put:
@@ -375,6 +400,7 @@ static void mic_remove(struct pci_dev *pdev)
 		return;
 
 	mic_stop(mdev, false);
+	cdev_del(&mdev->cdev);
 	mic_delete_debug_dir(mdev);
 	mutex_lock(&mdev->mic_mutex);
 	mic_free_irq(mdev, mdev->shutdown_cookie, mdev);