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drivers/vhost-rng: add vhost rng driver support for NuttX
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vhost-rng is a simple virtio device implementation, it receives
the buffer receviced from the virtio-rng driver and fill the random
number to this buffer and return to virtio-rng.

Signed-off-by: Bowen Wang <[email protected]>
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CV-Bowen authored and xiaoxiang781216 committed Oct 3, 2024
1 parent 7afbcc1 commit c42576e
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Showing 6 changed files with 275 additions and 0 deletions.
4 changes: 4 additions & 0 deletions drivers/vhost/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -23,5 +23,9 @@ if(CONFIG_DRIVERS_VHOST)
list(APPEND SRCS vhost.c)
endif()

if(CONFIG_DRIVERS_VHOST_RNG)
list(APPEND SRCS vhost_rng.c)
endif()

target_sources(drivers PRIVATE ${SRCS})
target_include_directories(drivers PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
4 changes: 4 additions & 0 deletions drivers/vhost/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -10,4 +10,8 @@ menuconfig DRIVERS_VHOST

if DRIVERS_VHOST

config DRIVERS_VHOST_RNG
bool "Virtual Host Rng Device Support"
default n

endif # DRIVERS_VHOST
4 changes: 4 additions & 0 deletions drivers/vhost/Make.defs
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,10 @@ ifeq ($(CONFIG_DRIVERS_VHOST),y)
CSRCS += vhost.c
endif

ifeq ($(CONFIG_DRIVERS_VHOST_RNG),y)
CSRCS += vhost-rng.c
endif

# Include build support

DEPPATH += --dep-path vhost
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189 changes: 189 additions & 0 deletions drivers/vhost/vhost-rng.c
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@@ -0,0 +1,189 @@
/****************************************************************************
* drivers/vhost/vhost-rng.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/

/****************************************************************************
* Included Files
****************************************************************************/

#include <debug.h>
#include <errno.h>
#include <stdio.h>
#include <sys/random.h>

#include <nuttx/kmalloc.h>
#include <nuttx/vhost/vhost.h>
#include <nuttx/wqueue.h>

/****************************************************************************
* Pre-processor Definitions
****************************************************************************/

/****************************************************************************
* Private Types
****************************************************************************/

struct vhost_rng_priv_s
{
FAR struct vhost_device *hdev;
struct work_s work;
};

/****************************************************************************
* Private Function Prototypes
****************************************************************************/

/* Vhost driver functions */

static int vhost_rng_probe(FAR struct vhost_device *hdev);
static void vhost_rng_remove(FAR struct vhost_device *hdev);

static void vhost_rng_work(FAR void *arg);
static void vhost_rng_handler(FAR struct virtqueue *vq);

/****************************************************************************
* Private Data
****************************************************************************/

static struct vhost_driver g_vhost_rng_driver =
{
LIST_INITIAL_VALUE(g_vhost_rng_driver.node), /* Node */
VIRTIO_ID_ENTROPY, /* Device id */
vhost_rng_probe, /* Probe */
vhost_rng_remove, /* Remove */
};

/****************************************************************************
* Private Functions
****************************************************************************/

/****************************************************************************
* Name: vhost_rng_thread
****************************************************************************/

static void vhost_rng_work(FAR void *arg)
{
FAR struct vhost_rng_priv_s *priv = arg;
FAR struct virtqueue *vq;
FAR void *buf;
uint16_t idx;
uint32_t len;
ssize_t ret;

vq = priv->hdev->vrings_info[0].vq;
for (; ; )
{
buf = virtqueue_get_available_buffer(vq, &idx, &len);
if (buf == NULL)
{
break;
}

ret = getrandom(buf, len, 0);
if (ret < 0)
{
vhosterr("getrandom failed, ret=%zd\n", ret);
ret = 0;
}

virtqueue_add_consumed_buffer(vq, idx, (uint32_t)ret);
virtqueue_kick(vq);
}
}

/****************************************************************************
* Name: vhost_rng_handler
****************************************************************************/

static void vhost_rng_handler(FAR struct virtqueue *vq)
{
FAR struct vhost_rng_priv_s *priv = vq->vq_dev->priv;

if (work_available(&priv->work))
{
work_queue(HPWORK, &priv->work, vhost_rng_work, priv, 0);
}
}

/****************************************************************************
* Name: vhost_rng_probe
****************************************************************************/

static int vhost_rng_probe(FAR struct vhost_device *hdev)
{
FAR struct vhost_rng_priv_s *priv;
FAR const char *vqnames[1];
vq_callback callback[1];
int ret;

priv = kmm_zalloc(sizeof(*priv));
if (priv == NULL)
{
vhosterr("No enough memory\n");
return -ENOMEM;
}

priv->hdev = hdev;
hdev->priv = priv;

/* Create the virtqueues */

vqnames[0] = "virtio_rng";
callback[0] = vhost_rng_handler;
ret = vhost_create_virtqueues(hdev, 0, 1, vqnames, callback);
if (ret < 0)
{
vhosterr("virtio_device_create_virtqueue failed, ret=%d\n", ret);
goto err;
}

virtqueue_enable_cb(hdev->vrings_info[0].vq);
return ret;

err:
kmm_free(priv);
return ret;
}

/****************************************************************************
* Name: vhost_rng_remove
****************************************************************************/

static void vhost_rng_remove(FAR struct vhost_device *hdev)
{
FAR struct vhost_rng_priv_s *priv = hdev->priv;

virtqueue_disable_cb(hdev->vrings_info[0].vq);
work_cancel_sync(HPWORK, &priv->work);
vhost_delete_virtqueues(hdev);
kmm_free(priv);
}

/****************************************************************************
* Public Functions
****************************************************************************/

/****************************************************************************
* Name: vhost_register_rng_driver
****************************************************************************/

int vhost_register_rng_driver(void)
{
return vhost_register_driver(&g_vhost_rng_driver);
}
61 changes: 61 additions & 0 deletions drivers/vhost/vhost-rng.h
Original file line number Diff line number Diff line change
@@ -0,0 +1,61 @@
/****************************************************************************
* drivers/vhost/vhost-rng.h
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/

#ifndef __DRIVERS_VHOST_VHOST_RNG_H
#define __DRIVERS_VHOST_VHOST_RNG_H

/****************************************************************************
* Included Files
****************************************************************************/

#include <nuttx/config.h>

#ifdef CONFIG_DRIVERS_VHOST_RNG

/****************************************************************************
* Pre-processor Definitions
****************************************************************************/

/****************************************************************************
* Public Data
****************************************************************************/

#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif

/****************************************************************************
* Public Function Prototypes
****************************************************************************/

int vhost_register_rng_driver(void);

#undef EXTERN
#ifdef __cplusplus
}
#endif

#endif /* CONFIG_DRIVERS_VHOST_RNG */

#endif /* __DRIVERS_VHOST_VHOST_RNG_H */
13 changes: 13 additions & 0 deletions drivers/vhost/vhost.c
Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,8 @@
#include <nuttx/wqueue.h>
#include <nuttx/vhost/vhost.h>

#include "vhost-rng.h"

/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
Expand Down Expand Up @@ -375,4 +377,15 @@ int vhost_unregister_device(FAR struct vhost_device *device)

void vhost_register_drivers(void)
{
int ret;

#ifdef CONFIG_DRIVERS_VHOST_RNG
ret = vhost_register_rng_driver();
if (ret < 0)
{
vrterr("vhost_register_rng_driver failed, ret=%d\n", ret);
}
#endif

UNUSED(ret);
}

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