crypto: add virtio-crypto driver

This patch introduces virtio-crypto driver for Linux Kernel.

The virtio crypto device is a virtual cryptography device
as well as a kind of virtual hardware accelerator for
virtual machines. The encryption anddecryption requests
are placed in the data queue and are ultimately handled by
thebackend crypto accelerators. The second queue is the
control queue used to create or destroy sessions for
symmetric algorithms and will control some advanced features
in the future. The virtio crypto device provides the following
cryptoservices: CIPHER, MAC, HASH, and AEAD.

For more information about virtio-crypto device, please see:
  http://qemu-project.org/Features/VirtioCrypto

CC: Michael S. Tsirkin <mst@redhat.com>
CC: Cornelia Huck <cornelia.huck@de.ibm.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: Halil Pasic <pasic@linux.vnet.ibm.com>
CC: David S. Miller <davem@davemloft.net>
CC: Zeng Xin <xin.zeng@intel.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 264 insertions, 0 deletions

diff --git a/drivers/crypto/virtio/virtio_crypto_mgr.c b/drivers/crypto/virtio/virtio_crypto_mgr.c
new file mode 100644
index 000000000000..a69ff71de2c4
--- /dev/null
+++ b/drivers/crypto/virtio/virtio_crypto_mgr.c
@@ -0,0 +1,264 @@
+ /* Management for virtio crypto devices (refer to adf_dev_mgr.c)
+  *
+  * Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
+  *
+  * This program is free software; you can redistribute it and/or modify
+  * it under the terms of the GNU General Public License as published by
+  * the Free Software Foundation; either version 2 of the License, or
+  * (at your option) any later version.
+  *
+  * This program is distributed in the hope that it will be useful,
+  * but WITHOUT ANY WARRANTY; without even the implied warranty of
+  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  * GNU General Public License for more details.
+  *
+  * You should have received a copy of the GNU General Public License
+  * along with this program; if not, see <http://www.gnu.org/licenses/>.
+  */
+
+#include <linux/mutex.h>
+#include <linux/list.h>
+#include <linux/module.h>
+
+#include <uapi/linux/virtio_crypto.h>
+#include "virtio_crypto_common.h"
+
+static LIST_HEAD(virtio_crypto_table);
+static uint32_t num_devices;
+
+/* The table_lock protects the above global list and num_devices */
+static DEFINE_MUTEX(table_lock);
+
+#define VIRTIO_CRYPTO_MAX_DEVICES 32
+
+
+/*
+ * virtcrypto_devmgr_add_dev() - Add vcrypto_dev to the acceleration
+ * framework.
+ * @vcrypto_dev:  Pointer to virtio crypto device.
+ *
+ * Function adds virtio crypto device to the global list.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: 0 on success, error code othewise.
+ */
+int virtcrypto_devmgr_add_dev(struct virtio_crypto *vcrypto_dev)
+{
+        struct list_head *itr;
+
+        mutex_lock(&table_lock);
+        if (num_devices == VIRTIO_CRYPTO_MAX_DEVICES) {
+                pr_info("virtio_crypto: only support up to %d devices\n",
+                            VIRTIO_CRYPTO_MAX_DEVICES);
+                mutex_unlock(&table_lock);
+                return -EFAULT;
+        }
+
+        list_for_each(itr, &virtio_crypto_table) {
+                struct virtio_crypto *ptr =
+                                list_entry(itr, struct virtio_crypto, list);
+
+                if (ptr == vcrypto_dev) {
+                        mutex_unlock(&table_lock);
+                        return -EEXIST;
+                }
+        }
+        atomic_set(&vcrypto_dev->ref_count, 0);
+        list_add_tail(&vcrypto_dev->list, &virtio_crypto_table);
+        vcrypto_dev->dev_id = num_devices++;
+        mutex_unlock(&table_lock);
+        return 0;
+}
+
+struct list_head *virtcrypto_devmgr_get_head(void)
+{
+        return &virtio_crypto_table;
+}
+
+/*
+ * virtcrypto_devmgr_rm_dev() - Remove vcrypto_dev from the acceleration
+ * framework.
+ * @vcrypto_dev:  Pointer to virtio crypto device.
+ *
+ * Function removes virtio crypto device from the acceleration framework.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: void
+ */
+void virtcrypto_devmgr_rm_dev(struct virtio_crypto *vcrypto_dev)
+{
+        mutex_lock(&table_lock);
+        list_del(&vcrypto_dev->list);
+        num_devices--;
+        mutex_unlock(&table_lock);
+}
+
+/*
+ * virtcrypto_devmgr_get_first()
+ *
+ * Function returns the first virtio crypto device from the acceleration
+ * framework.
+ *
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: pointer to vcrypto_dev or NULL if not found.
+ */
+struct virtio_crypto *virtcrypto_devmgr_get_first(void)
+{
+        struct virtio_crypto *dev = NULL;
+
+        mutex_lock(&table_lock);
+        if (!list_empty(&virtio_crypto_table))
+                dev = list_first_entry(&virtio_crypto_table,
+                                        struct virtio_crypto,
+                                    list);
+        mutex_unlock(&table_lock);
+        return dev;
+}
+
+/*
+ * virtcrypto_dev_in_use() - Check whether vcrypto_dev is currently in use
+ * @vcrypto_dev: Pointer to virtio crypto device.
+ *
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: 1 when device is in use, 0 otherwise.
+ */
+int virtcrypto_dev_in_use(struct virtio_crypto *vcrypto_dev)
+{
+        return atomic_read(&vcrypto_dev->ref_count) != 0;
+}
+
+/*
+ * virtcrypto_dev_get() - Increment vcrypto_dev reference count
+ * @vcrypto_dev: Pointer to virtio crypto device.
+ *
+ * Increment the vcrypto_dev refcount and if this is the first time
+ * incrementing it during this period the vcrypto_dev is in use,
+ * increment the module refcount too.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: 0 when successful, EFAULT when fail to bump module refcount
+ */
+int virtcrypto_dev_get(struct virtio_crypto *vcrypto_dev)
+{
+        if (atomic_add_return(1, &vcrypto_dev->ref_count) == 1)
+                if (!try_module_get(vcrypto_dev->owner))
+                        return -EFAULT;
+        return 0;
+}
+
+/*
+ * virtcrypto_dev_put() - Decrement vcrypto_dev reference count
+ * @vcrypto_dev: Pointer to virtio crypto device.
+ *
+ * Decrement the vcrypto_dev refcount and if this is the last time
+ * decrementing it during this period the vcrypto_dev is in use,
+ * decrement the module refcount too.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: void
+ */
+void virtcrypto_dev_put(struct virtio_crypto *vcrypto_dev)
+{
+        if (atomic_sub_return(1, &vcrypto_dev->ref_count) == 0)
+                module_put(vcrypto_dev->owner);
+}
+
+/*
+ * virtcrypto_dev_started() - Check whether device has started
+ * @vcrypto_dev: Pointer to virtio crypto device.
+ *
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: 1 when the device has started, 0 otherwise
+ */
+int virtcrypto_dev_started(struct virtio_crypto *vcrypto_dev)
+{
+        return (vcrypto_dev->status & VIRTIO_CRYPTO_S_HW_READY);
+}
+
+/*
+ * virtcrypto_get_dev_node() - Get vcrypto_dev on the node.
+ * @node:  Node id the driver works.
+ *
+ * Function returns the virtio crypto device used fewest on the node.
+ *
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: pointer to vcrypto_dev or NULL if not found.
+ */
+struct virtio_crypto *virtcrypto_get_dev_node(int node)
+{
+        struct virtio_crypto *vcrypto_dev = NULL, *tmp_dev;
+        unsigned long best = ~0;
+        unsigned long ctr;
+
+        mutex_lock(&table_lock);
+        list_for_each_entry(tmp_dev, virtcrypto_devmgr_get_head(), list) {
+
+                if ((node == dev_to_node(&tmp_dev->vdev->dev) ||
+                     dev_to_node(&tmp_dev->vdev->dev) < 0) &&
+                    virtcrypto_dev_started(tmp_dev)) {
+                        ctr = atomic_read(&tmp_dev->ref_count);
+                        if (best > ctr) {
+                                vcrypto_dev = tmp_dev;
+                                best = ctr;
+                        }
+                }
+        }
+
+        if (!vcrypto_dev) {
+                pr_info("virtio_crypto: Could not find a device on node %d\n",
+                                node);
+                /* Get any started device */
+                list_for_each_entry(tmp_dev,
+                                virtcrypto_devmgr_get_head(), list) {
+                        if (virtcrypto_dev_started(tmp_dev)) {
+                                vcrypto_dev = tmp_dev;
+                                break;
+                        }
+                }
+        }
+        mutex_unlock(&table_lock);
+        if (!vcrypto_dev)
+                return NULL;
+
+        virtcrypto_dev_get(vcrypto_dev);
+        return vcrypto_dev;
+}
+
+/*
+ * virtcrypto_dev_start() - Start virtio crypto device
+ * @vcrypto:    Pointer to virtio crypto device.
+ *
+ * Function notifies all the registered services that the virtio crypto device
+ * is ready to be used.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: 0 on success, EFAULT when fail to register algorithms
+ */
+int virtcrypto_dev_start(struct virtio_crypto *vcrypto)
+{
+        if (virtio_crypto_algs_register()) {
+                pr_err("virtio_crypto: Failed to register crypto algs\n");
+                return -EFAULT;
+        }
+
+        return 0;
+}
+
+/*
+ * virtcrypto_dev_stop() - Stop virtio crypto device
+ * @vcrypto:    Pointer to virtio crypto device.
+ *
+ * Function notifies all the registered services that the virtio crypto device
+ * is ready to be used.
+ * To be used by virtio crypto device specific drivers.
+ *
+ * Return: void
+ */
+void virtcrypto_dev_stop(struct virtio_crypto *vcrypto)
+{
+        virtio_crypto_algs_unregister();
+}