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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Virtio vhost-user driver
*
* Copyright(c) 2019 Intel Corporation
*
* This driver allows virtio devices to be used over a vhost-user socket.
*
* Guest devices can be instantiated by kernel module or command line
* parameters. One device will be created for each parameter. Syntax:
*
* virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]
* where:
* <socket> := vhost-user socket path to connect
* <virtio_id> := virtio device id (as in virtio_ids.h)
* <platform_id> := (optional) platform device id
*
* example:
* virtio_uml.device=/var/uml.socket:1
*
* Based on Virtio MMIO driver by Pawel Moll, copyright 2011-2014, ARM Ltd.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/virtio_ring.h>
#include <linux/time-internal.h>
#include <shared/as-layout.h>
#include <irq_kern.h>
#include <init.h>
#include <os.h>
#include "vhost_user.h"
/* Workaround due to a conflict between irq_user.h and irqreturn.h */
#ifdef IRQ_NONE
#undef IRQ_NONE
#endif
#define MAX_SUPPORTED_QUEUE_SIZE 256
#define to_virtio_uml_device(_vdev) \
container_of(_vdev, struct virtio_uml_device, vdev)
struct virtio_uml_platform_data {
u32 virtio_device_id;
const char *socket_path;
struct work_struct conn_broken_wk;
struct platform_device *pdev;
};
struct virtio_uml_device {
struct virtio_device vdev;
struct platform_device *pdev;
spinlock_t sock_lock;
int sock, req_fd;
u64 features;
u64 protocol_features;
u8 status;
u8 registered:1;
};
struct virtio_uml_vq_info {
int kick_fd, call_fd;
char name[32];
#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
struct virtqueue *vq;
vq_callback_t *callback;
struct time_travel_event defer;
#endif
};
extern unsigned long long physmem_size, highmem;
#define vu_err(vu_dev, ...) dev_err(&(vu_dev)->pdev->dev, ##__VA_ARGS__)
/* Vhost-user protocol */
static int full_sendmsg_fds(int fd, const void *buf, unsigned int len,
const int *fds, unsigned int fds_num)
{
int rc;
do {
rc = os_sendmsg_fds(fd, buf, len, fds, fds_num);
if (rc > 0) {
buf += rc;
len -= rc;
fds = NULL;
fds_num = 0;
}
} while (len && (rc >= 0 || rc == -EINTR));
if (rc < 0)
return rc;
return 0;
}
static int full_read(int fd, void *buf, int len, bool abortable)
{
int rc;
do {
rc = os_read_file(fd, buf, len);
if (rc > 0) {
buf += rc;
len -= rc;
}
} while (len && (rc > 0 || rc == -EINTR || (!abortable && rc == -EAGAIN)));
if (rc < 0)
return rc;
if (rc == 0)
return -ECONNRESET;
return 0;
}
static int vhost_user_recv_header(int fd, struct vhost_user_msg *msg)
{
return full_read(fd, msg, sizeof(msg->header), true);
}
static int vhost_user_recv(struct virtio_uml_device *vu_dev,
int fd, struct vhost_user_msg *msg,
size_t max_payload_size, bool wait)
{
size_t size;
int rc;
/*
* In virtio time-travel mode, we're handling all the vhost-user
* FDs by polling them whenever appropriate. However, we may get
* into a situation where we're sending out an interrupt message
* to a device (e.g. a net device) and need to handle a simulation
* time message while doing so, e.g. one that tells us to update
* our idea of how long we can run without scheduling.
*
* Thus, we need to not just read() from the given fd, but need
* to also handle messages for the simulation time - this function
* does that for us while waiting for the given fd to be readable.
*/
if (wait)
time_travel_wait_readable(fd);
rc = vhost_user_recv_header(fd, msg);
if (rc == -ECONNRESET && vu_dev->registered) {
struct virtio_uml_platform_data *pdata;
pdata = vu_dev->pdev->dev.platform_data;
virtio_break_device(&vu_dev->vdev);
schedule_work(&pdata->conn_broken_wk);
}
if (rc)
return rc;
size = msg->header.size;
if (size > max_payload_size)
return -EPROTO;
return full_read(fd, &msg->payload, size, false);
}
static int vhost_user_recv_resp(struct virtio_uml_device *vu_dev,
struct vhost_user_msg *msg,
size_t max_payload_size)
{
int rc = vhost_user_recv(vu_dev, vu_dev->sock, msg,
max_payload_size, true);
if (rc)
return rc;
if (msg->header.flags != (VHOST_USER_FLAG_REPLY | VHOST_USER_VERSION))
return -EPROTO;
return 0;
}
static int vhost_user_recv_u64(struct virtio_uml_device *vu_dev,
u64 *value)
{
struct vhost_user_msg msg;
int rc = vhost_user_recv_resp(vu_dev, &msg,
sizeof(msg.payload.integer));
if (rc)
return rc;
if (msg.header.size != sizeof(msg.payload.integer))
return -EPROTO;
*value = msg.payload.integer;
return 0;
}
static int vhost_user_recv_req(struct virtio_uml_device *vu_dev,
struct vhost_user_msg *msg,
size_t max_payload_size)
{
int rc = vhost_user_recv(vu_dev, vu_dev->req_fd, msg,
max_payload_size, false);
if (rc)
return rc;
if ((msg->header.flags & ~VHOST_USER_FLAG_NEED_REPLY) !=
VHOST_USER_VERSION)
return -EPROTO;
return 0;
}
static int vhost_user_send(struct virtio_uml_device *vu_dev,
bool need_response, struct vhost_user_msg *msg,
int *fds, size_t num_fds)
{
size_t size = sizeof(msg->header) + msg->header.size;
unsigned long flags;
bool request_ack;
int rc;
msg->header.flags |= VHOST_USER_VERSION;
/*
* The need_response flag indicates that we already need a response,
* e.g. to read the features. In these cases, don't request an ACK as
* it is meaningless. Also request an ACK only if supported.
*/
request_ack = !need_response;
if (!(vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_REPLY_ACK)))
request_ack = false;
if (request_ack)
msg->header.flags |= VHOST_USER_FLAG_NEED_REPLY;
spin_lock_irqsave(&vu_dev->sock_lock, flags);
rc = full_sendmsg_fds(vu_dev->sock, msg, size, fds, num_fds);
if (rc < 0)
goto out;
if (request_ack) {
uint64_t status;
rc = vhost_user_recv_u64(vu_dev, &status);
if (rc)
goto out;
if (status) {
vu_err(vu_dev, "slave reports error: %llu\n", status);
rc = -EIO;
goto out;
}
}
out:
spin_unlock_irqrestore(&vu_dev->sock_lock, flags);
return rc;
}
static int vhost_user_send_no_payload(struct virtio_uml_device *vu_dev,
bool need_response, u32 request)
{
struct vhost_user_msg msg = {
.header.request = request,
};
return vhost_user_send(vu_dev, need_response, &msg, NULL, 0);
}
static int vhost_user_send_no_payload_fd(struct virtio_uml_device *vu_dev,
u32 request, int fd)
{
struct vhost_user_msg msg = {
.header.request = request,
};
return vhost_user_send(vu_dev, false, &msg, &fd, 1);
}
static int vhost_user_send_u64(struct virtio_uml_device *vu_dev,
u32 request, u64 value)
{
struct vhost_user_msg msg = {
.header.request = request,
.header.size = sizeof(msg.payload.integer),
.payload.integer = value,
};
return vhost_user_send(vu_dev, false, &msg, NULL, 0);
}
static int vhost_user_set_owner(struct virtio_uml_device *vu_dev)
{
return vhost_user_send_no_payload(vu_dev, false, VHOST_USER_SET_OWNER);
}
static int vhost_user_get_features(struct virtio_uml_device *vu_dev,
u64 *features)
{
int rc = vhost_user_send_no_payload(vu_dev, true,
VHOST_USER_GET_FEATURES);
if (rc)
return rc;
return vhost_user_recv_u64(vu_dev, features);
}
static int vhost_user_set_features(struct virtio_uml_device *vu_dev,
u64 features)
{
return vhost_user_send_u64(vu_dev, VHOST_USER_SET_FEATURES, features);
}
static int vhost_user_get_protocol_features(struct virtio_uml_device *vu_dev,
u64 *protocol_features)
{
int rc = vhost_user_send_no_payload(vu_dev, true,
VHOST_USER_GET_PROTOCOL_FEATURES);
if (rc)
return rc;
return vhost_user_recv_u64(vu_dev, protocol_features);
}
static int vhost_user_set_protocol_features(struct virtio_uml_device *vu_dev,
u64 protocol_features)
{
return vhost_user_send_u64(vu_dev, VHOST_USER_SET_PROTOCOL_FEATURES,
protocol_features);
}
static void vhost_user_reply(struct virtio_uml_device *vu_dev,
struct vhost_user_msg *msg, int response)
{
struct vhost_user_msg reply = {
.payload.integer = response,
};
size_t size = sizeof(reply.header) + sizeof(reply.payload.integer);
int rc;
reply.header = msg->header;
reply.header.flags &= ~VHOST_USER_FLAG_NEED_REPLY;
reply.header.flags |= VHOST_USER_FLAG_REPLY;
reply.header.size = sizeof(reply.payload.integer);
rc = full_sendmsg_fds(vu_dev->req_fd, &reply, size, NULL, 0);
if (rc)
vu_err(vu_dev,
"sending reply to slave request failed: %d (size %zu)\n",
rc, size);
}
static irqreturn_t vu_req_interrupt(int irq, void *data)
{
struct virtio_uml_device *vu_dev = data;
struct virtqueue *vq;
int response = 1;
struct {
struct vhost_user_msg msg;
u8 extra_payload[512];
} msg;
int rc;
rc = vhost_user_recv_req(vu_dev, &msg.msg,
sizeof(msg.msg.payload) +
sizeof(msg.extra_payload));
if (rc)
return IRQ_NONE;
switch (msg.msg.header.request) {
case VHOST_USER_SLAVE_CONFIG_CHANGE_MSG:
virtio_config_changed(&vu_dev->vdev);
response = 0;
break;
case VHOST_USER_SLAVE_VRING_CALL:
virtio_device_for_each_vq((&vu_dev->vdev), vq) {
if (vq->index == msg.msg.payload.vring_state.index) {
response = 0;
vring_interrupt(0 /* ignored */, vq);
break;
}
}
break;
case VHOST_USER_SLAVE_IOTLB_MSG:
/* not supported - VIRTIO_F_ACCESS_PLATFORM */
case VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG:
/* not supported - VHOST_USER_PROTOCOL_F_HOST_NOTIFIER */
default:
vu_err(vu_dev, "unexpected slave request %d\n",
msg.msg.header.request);
}
if (msg.msg.header.flags & VHOST_USER_FLAG_NEED_REPLY)
vhost_user_reply(vu_dev, &msg.msg, response);
return IRQ_HANDLED;
}
static int vhost_user_init_slave_req(struct virtio_uml_device *vu_dev)
{
int rc, req_fds[2];
/* Use a pipe for slave req fd, SIGIO is not supported for eventfd */
rc = os_pipe(req_fds, true, true);
if (rc < 0)
return rc;
vu_dev->req_fd = req_fds[0];
rc = um_request_irq(VIRTIO_IRQ, vu_dev->req_fd, IRQ_READ,
vu_req_interrupt, IRQF_SHARED,
vu_dev->pdev->name, vu_dev);
if (rc)
goto err_close;
rc = vhost_user_send_no_payload_fd(vu_dev, VHOST_USER_SET_SLAVE_REQ_FD,
req_fds[1]);
if (rc)
goto err_free_irq;
goto out;
err_free_irq:
um_free_irq(VIRTIO_IRQ, vu_dev);
err_close:
os_close_file(req_fds[0]);
out:
/* Close unused write end of request fds */
os_close_file(req_fds[1]);
return rc;
}
static int vhost_user_init(struct virtio_uml_device *vu_dev)
{
int rc = vhost_user_set_owner(vu_dev);
if (rc)
return rc;
rc = vhost_user_get_features(vu_dev, &vu_dev->features);
if (rc)
return rc;
if (vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)) {
rc = vhost_user_get_protocol_features(vu_dev,
&vu_dev->protocol_features);
if (rc)
return rc;
vu_dev->protocol_features &= VHOST_USER_SUPPORTED_PROTOCOL_F;
rc = vhost_user_set_protocol_features(vu_dev,
vu_dev->protocol_features);
if (rc)
return rc;
}
if (vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
rc = vhost_user_init_slave_req(vu_dev);
if (rc)
return rc;
}
return 0;
}
static void vhost_user_get_config(struct virtio_uml_device *vu_dev,
u32 offset, void *buf, u32 len)
{
u32 cfg_size = offset + len;
struct vhost_user_msg *msg;
size_t payload_size = sizeof(msg->payload.config) + cfg_size;
size_t msg_size = sizeof(msg->header) + payload_size;
int rc;
if (!(vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
return;
msg = kzalloc(msg_size, GFP_KERNEL);
if (!msg)
return;
msg->header.request = VHOST_USER_GET_CONFIG;
msg->header.size = payload_size;
msg->payload.config.offset = 0;
msg->payload.config.size = cfg_size;
rc = vhost_user_send(vu_dev, true, msg, NULL, 0);
if (rc) {
vu_err(vu_dev, "sending VHOST_USER_GET_CONFIG failed: %d\n",
rc);
goto free;
}
rc = vhost_user_recv_resp(vu_dev, msg, msg_size);
if (rc) {
vu_err(vu_dev,
"receiving VHOST_USER_GET_CONFIG response failed: %d\n",
rc);
goto free;
}
if (msg->header.size != payload_size ||
msg->payload.config.size != cfg_size) {
rc = -EPROTO;
vu_err(vu_dev,
"Invalid VHOST_USER_GET_CONFIG sizes (payload %d expected %zu, config %u expected %u)\n",
msg->header.size, payload_size,
msg->payload.config.size, cfg_size);
goto free;
}
memcpy(buf, msg->payload.config.payload + offset, len);
free:
kfree(msg);
}
static void vhost_user_set_config(struct virtio_uml_device *vu_dev,
u32 offset, const void *buf, u32 len)
{
struct vhost_user_msg *msg;
size_t payload_size = sizeof(msg->payload.config) + len;
size_t msg_size = sizeof(msg->header) + payload_size;
int rc;
if (!(vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_CONFIG)))
return;
msg = kzalloc(msg_size, GFP_KERNEL);
if (!msg)
return;
msg->header.request = VHOST_USER_SET_CONFIG;
msg->header.size = payload_size;
msg->payload.config.offset = offset;
msg->payload.config.size = len;
memcpy(msg->payload.config.payload, buf, len);
rc = vhost_user_send(vu_dev, false, msg, NULL, 0);
if (rc)
vu_err(vu_dev, "sending VHOST_USER_SET_CONFIG failed: %d\n",
rc);
kfree(msg);
}
static int vhost_user_init_mem_region(u64 addr, u64 size, int *fd_out,
struct vhost_user_mem_region *region_out)
{
unsigned long long mem_offset;
int rc = phys_mapping(addr, &mem_offset);
if (WARN(rc < 0, "phys_mapping of 0x%llx returned %d\n", addr, rc))
return -EFAULT;
*fd_out = rc;
region_out->guest_addr = addr;
region_out->user_addr = addr;
region_out->size = size;
region_out->mmap_offset = mem_offset;
/* Ensure mapping is valid for the entire region */
rc = phys_mapping(addr + size - 1, &mem_offset);
if (WARN(rc != *fd_out, "phys_mapping of 0x%llx failed: %d != %d\n",
addr + size - 1, rc, *fd_out))
return -EFAULT;
return 0;
}
static int vhost_user_set_mem_table(struct virtio_uml_device *vu_dev)
{
struct vhost_user_msg msg = {
.header.request = VHOST_USER_SET_MEM_TABLE,
.header.size = sizeof(msg.payload.mem_regions),
.payload.mem_regions.num = 1,
};
unsigned long reserved = uml_reserved - uml_physmem;
int fds[2];
int rc;
/*
* This is a bit tricky, see also the comment with setup_physmem().
*
* Essentially, setup_physmem() uses a file to mmap() our physmem,
* but the code and data we *already* have is omitted. To us, this
* is no difference, since they both become part of our address
* space and memory consumption. To somebody looking in from the
* outside, however, it is different because the part of our memory
* consumption that's already part of the binary (code/data) is not
* mapped from the file, so it's not visible to another mmap from
* the file descriptor.
*
* Thus, don't advertise this space to the vhost-user slave. This
* means that the slave will likely abort or similar when we give
* it an address from the hidden range, since it's not marked as
* a valid address, but at least that way we detect the issue and
* don't just have the slave read an all-zeroes buffer from the
* shared memory file, or write something there that we can never
* see (depending on the direction of the virtqueue traffic.)
*
* Since we usually don't want to use .text for virtio buffers,
* this effectively means that you cannot use
* 1) global variables, which are in the .bss and not in the shm
* file-backed memory
* 2) the stack in some processes, depending on where they have
* their stack (or maybe only no interrupt stack?)
*
* The stack is already not typically valid for DMA, so this isn't
* much of a restriction, but global variables might be encountered.
*
* It might be possible to fix it by copying around the data that's
* between bss_start and where we map the file now, but it's not
* something that you typically encounter with virtio drivers, so
* it didn't seem worthwhile.
*/
rc = vhost_user_init_mem_region(reserved, physmem_size - reserved,
&fds[0],
&msg.payload.mem_regions.regions[0]);
if (rc < 0)
return rc;
if (highmem) {
msg.payload.mem_regions.num++;
rc = vhost_user_init_mem_region(__pa(end_iomem), highmem,
&fds[1], &msg.payload.mem_regions.regions[1]);
if (rc < 0)
return rc;
}
return vhost_user_send(vu_dev, false, &msg, fds,
msg.payload.mem_regions.num);
}
static int vhost_user_set_vring_state(struct virtio_uml_device *vu_dev,
u32 request, u32 index, u32 num)
{
struct vhost_user_msg msg = {
.header.request = request,
.header.size = sizeof(msg.payload.vring_state),
.payload.vring_state.index = index,
.payload.vring_state.num = num,
};
return vhost_user_send(vu_dev, false, &msg, NULL, 0);
}
static int vhost_user_set_vring_num(struct virtio_uml_device *vu_dev,
u32 index, u32 num)
{
return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_NUM,
index, num);
}
static int vhost_user_set_vring_base(struct virtio_uml_device *vu_dev,
u32 index, u32 offset)
{
return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_BASE,
index, offset);
}
static int vhost_user_set_vring_addr(struct virtio_uml_device *vu_dev,
u32 index, u64 desc, u64 used, u64 avail,
u64 log)
{
struct vhost_user_msg msg = {
.header.request = VHOST_USER_SET_VRING_ADDR,
.header.size = sizeof(msg.payload.vring_addr),
.payload.vring_addr.index = index,
.payload.vring_addr.desc = desc,
.payload.vring_addr.used = used,
.payload.vring_addr.avail = avail,
.payload.vring_addr.log = log,
};
return vhost_user_send(vu_dev, false, &msg, NULL, 0);
}
static int vhost_user_set_vring_fd(struct virtio_uml_device *vu_dev,
u32 request, int index, int fd)
{
struct vhost_user_msg msg = {
.header.request = request,
.header.size = sizeof(msg.payload.integer),
.payload.integer = index,
};
if (index & ~VHOST_USER_VRING_INDEX_MASK)
return -EINVAL;
if (fd < 0) {
msg.payload.integer |= VHOST_USER_VRING_POLL_MASK;
return vhost_user_send(vu_dev, false, &msg, NULL, 0);
}
return vhost_user_send(vu_dev, false, &msg, &fd, 1);
}
static int vhost_user_set_vring_call(struct virtio_uml_device *vu_dev,
int index, int fd)
{
return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_CALL,
index, fd);
}
static int vhost_user_set_vring_kick(struct virtio_uml_device *vu_dev,
int index, int fd)
{
return vhost_user_set_vring_fd(vu_dev, VHOST_USER_SET_VRING_KICK,
index, fd);
}
static int vhost_user_set_vring_enable(struct virtio_uml_device *vu_dev,
u32 index, bool enable)
{
if (!(vu_dev->features & BIT_ULL(VHOST_USER_F_PROTOCOL_FEATURES)))
return 0;
return vhost_user_set_vring_state(vu_dev, VHOST_USER_SET_VRING_ENABLE,
index, enable);
}
/* Virtio interface */
static bool vu_notify(struct virtqueue *vq)
{
struct virtio_uml_vq_info *info = vq->priv;
const uint64_t n = 1;
int rc;
time_travel_propagate_time();
if (info->kick_fd < 0) {
struct virtio_uml_device *vu_dev;
vu_dev = to_virtio_uml_device(vq->vdev);
return vhost_user_set_vring_state(vu_dev, VHOST_USER_VRING_KICK,
vq->index, 0) == 0;
}
do {
rc = os_write_file(info->kick_fd, &n, sizeof(n));
} while (rc == -EINTR);
return !WARN(rc != sizeof(n), "write returned %d\n", rc);
}
static irqreturn_t vu_interrupt(int irq, void *opaque)
{
struct virtqueue *vq = opaque;
struct virtio_uml_vq_info *info = vq->priv;
uint64_t n;
int rc;
irqreturn_t ret = IRQ_NONE;
do {
rc = os_read_file(info->call_fd, &n, sizeof(n));
if (rc == sizeof(n))
ret |= vring_interrupt(irq, vq);
} while (rc == sizeof(n) || rc == -EINTR);
WARN(rc != -EAGAIN, "read returned %d\n", rc);
return ret;
}
static void vu_get(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
vhost_user_get_config(vu_dev, offset, buf, len);
}
static void vu_set(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
vhost_user_set_config(vu_dev, offset, buf, len);
}
static u8 vu_get_status(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
return vu_dev->status;
}
static void vu_set_status(struct virtio_device *vdev, u8 status)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
vu_dev->status = status;
}
static void vu_reset(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
vu_dev->status = 0;
}
static void vu_del_vq(struct virtqueue *vq)
{
struct virtio_uml_vq_info *info = vq->priv;
if (info->call_fd >= 0) {
um_free_irq(VIRTIO_IRQ, vq);
os_close_file(info->call_fd);
}
if (info->kick_fd >= 0)
os_close_file(info->kick_fd);
vring_del_virtqueue(vq);
kfree(info);
}
static void vu_del_vqs(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
struct virtqueue *vq, *n;
u64 features;
/* Note: reverse order as a workaround to a decoding bug in snabb */
list_for_each_entry_reverse(vq, &vdev->vqs, list)
WARN_ON(vhost_user_set_vring_enable(vu_dev, vq->index, false));
/* Ensure previous messages have been processed */
WARN_ON(vhost_user_get_features(vu_dev, &features));
list_for_each_entry_safe(vq, n, &vdev->vqs, list)
vu_del_vq(vq);
}
static int vu_setup_vq_call_fd(struct virtio_uml_device *vu_dev,
struct virtqueue *vq)
{
struct virtio_uml_vq_info *info = vq->priv;
int call_fds[2];
int rc;
/* no call FD needed/desired in this case */
if (vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS) &&
vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_SLAVE_REQ)) {
info->call_fd = -1;
return 0;
}
/* Use a pipe for call fd, since SIGIO is not supported for eventfd */
rc = os_pipe(call_fds, true, true);
if (rc < 0)
return rc;
info->call_fd = call_fds[0];
rc = um_request_irq(VIRTIO_IRQ, info->call_fd, IRQ_READ,
vu_interrupt, IRQF_SHARED, info->name, vq);
if (rc)
goto close_both;
rc = vhost_user_set_vring_call(vu_dev, vq->index, call_fds[1]);
if (rc)
goto release_irq;
goto out;
release_irq:
um_free_irq(VIRTIO_IRQ, vq);
close_both:
os_close_file(call_fds[0]);
out:
/* Close (unused) write end of call fds */
os_close_file(call_fds[1]);
return rc;
}
#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
static void vu_defer_irq_handle(struct time_travel_event *d)
{
struct virtio_uml_vq_info *info;
info = container_of(d, struct virtio_uml_vq_info, defer);
info->callback(info->vq);
}
static void vu_defer_irq_callback(struct virtqueue *vq)
{
struct virtio_uml_vq_info *info = vq->priv;
time_travel_add_irq_event(&info->defer);
}
#endif
static struct virtqueue *vu_setup_vq(struct virtio_device *vdev,
unsigned index, vq_callback_t *callback,
const char *name, bool ctx)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
struct platform_device *pdev = vu_dev->pdev;
struct virtio_uml_vq_info *info;
struct virtqueue *vq;
int num = MAX_SUPPORTED_QUEUE_SIZE;
int rc;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
rc = -ENOMEM;
goto error_kzalloc;
}
snprintf(info->name, sizeof(info->name), "%s.%d-%s", pdev->name,
pdev->id, name);
#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
/*
* When we get an interrupt, we must bounce it through the simulation
* calendar (the simtime device), except for the simtime device itself
* since that's part of the simulation control.
*/
if (time_travel_mode == TT_MODE_EXTERNAL && callback) {
info->callback = callback;
callback = vu_defer_irq_callback;
time_travel_set_event_fn(&info->defer, vu_defer_irq_handle);
}
#endif
vq = vring_create_virtqueue(index, num, PAGE_SIZE, vdev, true, true,
ctx, vu_notify, callback, info->name);
if (!vq) {
rc = -ENOMEM;
goto error_create;
}
vq->priv = info;
num = virtqueue_get_vring_size(vq);
#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
info->vq = vq;
#endif
if (vu_dev->protocol_features &
BIT_ULL(VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS)) {
info->kick_fd = -1;
} else {
rc = os_eventfd(0, 0);
if (rc < 0)
goto error_kick;
info->kick_fd = rc;
}
rc = vu_setup_vq_call_fd(vu_dev, vq);
if (rc)
goto error_call;
rc = vhost_user_set_vring_num(vu_dev, index, num);
if (rc)
goto error_setup;
rc = vhost_user_set_vring_base(vu_dev, index, 0);
if (rc)
goto error_setup;
rc = vhost_user_set_vring_addr(vu_dev, index,
virtqueue_get_desc_addr(vq),
virtqueue_get_used_addr(vq),
virtqueue_get_avail_addr(vq),
(u64) -1);
if (rc)
goto error_setup;
return vq;
error_setup:
if (info->call_fd >= 0) {
um_free_irq(VIRTIO_IRQ, vq);
os_close_file(info->call_fd);
}
error_call:
if (info->kick_fd >= 0)
os_close_file(info->kick_fd);
error_kick:
vring_del_virtqueue(vq);
error_create:
kfree(info);
error_kzalloc:
return ERR_PTR(rc);
}
static int vu_find_vqs(struct virtio_device *vdev, unsigned nvqs,
struct virtqueue *vqs[], vq_callback_t *callbacks[],
const char * const names[], const bool *ctx,
struct irq_affinity *desc)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
int i, queue_idx = 0, rc;
struct virtqueue *vq;
rc = vhost_user_set_mem_table(vu_dev);
if (rc)
return rc;
for (i = 0; i < nvqs; ++i) {
if (!names[i]) {
vqs[i] = NULL;
continue;
}
vqs[i] = vu_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
ctx ? ctx[i] : false);
if (IS_ERR(vqs[i])) {
rc = PTR_ERR(vqs[i]);
goto error_setup;
}
}
list_for_each_entry(vq, &vdev->vqs, list) {
struct virtio_uml_vq_info *info = vq->priv;
if (info->kick_fd >= 0) {
rc = vhost_user_set_vring_kick(vu_dev, vq->index,
info->kick_fd);
if (rc)
goto error_setup;
}
rc = vhost_user_set_vring_enable(vu_dev, vq->index, true);
if (rc)
goto error_setup;
}
return 0;
error_setup:
vu_del_vqs(vdev);
return rc;
}
static u64 vu_get_features(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
return vu_dev->features;
}
static int vu_finalize_features(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
u64 supported = vdev->features & VHOST_USER_SUPPORTED_F;
vring_transport_features(vdev);
vu_dev->features = vdev->features | supported;
return vhost_user_set_features(vu_dev, vu_dev->features);
}
static const char *vu_bus_name(struct virtio_device *vdev)
{
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
return vu_dev->pdev->name;
}
static const struct virtio_config_ops virtio_uml_config_ops = {
.get = vu_get,
.set = vu_set,
.get_status = vu_get_status,
.set_status = vu_set_status,
.reset = vu_reset,
.find_vqs = vu_find_vqs,
.del_vqs = vu_del_vqs,
.get_features = vu_get_features,
.finalize_features = vu_finalize_features,
.bus_name = vu_bus_name,
};
static void virtio_uml_release_dev(struct device *d)
{
struct virtio_device *vdev =
container_of(d, struct virtio_device, dev);
struct virtio_uml_device *vu_dev = to_virtio_uml_device(vdev);
/* might not have been opened due to not negotiating the feature */
if (vu_dev->req_fd >= 0) {
um_free_irq(VIRTIO_IRQ, vu_dev);
os_close_file(vu_dev->req_fd);
}
os_close_file(vu_dev->sock);
}
/* Platform device */
static int virtio_uml_probe(struct platform_device *pdev)
{
struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
struct virtio_uml_device *vu_dev;
int rc;
if (!pdata)
return -EINVAL;
vu_dev = devm_kzalloc(&pdev->dev, sizeof(*vu_dev), GFP_KERNEL);
if (!vu_dev)
return -ENOMEM;
vu_dev->vdev.dev.parent = &pdev->dev;
vu_dev->vdev.dev.release = virtio_uml_release_dev;
vu_dev->vdev.config = &virtio_uml_config_ops;
vu_dev->vdev.id.device = pdata->virtio_device_id;
vu_dev->vdev.id.vendor = VIRTIO_DEV_ANY_ID;
vu_dev->pdev = pdev;
vu_dev->req_fd = -1;
do {
rc = os_connect_socket(pdata->socket_path);
} while (rc == -EINTR);
if (rc < 0)
return rc;
vu_dev->sock = rc;
spin_lock_init(&vu_dev->sock_lock);
rc = vhost_user_init(vu_dev);
if (rc)
goto error_init;
platform_set_drvdata(pdev, vu_dev);
rc = register_virtio_device(&vu_dev->vdev);
if (rc)
put_device(&vu_dev->vdev.dev);
vu_dev->registered = 1;
return rc;
error_init:
os_close_file(vu_dev->sock);
return rc;
}
static int virtio_uml_remove(struct platform_device *pdev)
{
struct virtio_uml_device *vu_dev = platform_get_drvdata(pdev);
unregister_virtio_device(&vu_dev->vdev);
return 0;
}
/* Command line device list */
static void vu_cmdline_release_dev(struct device *d)
{
}
static struct device vu_cmdline_parent = {
.init_name = "virtio-uml-cmdline",
.release = vu_cmdline_release_dev,
};
static bool vu_cmdline_parent_registered;
static int vu_cmdline_id;
static int vu_unregister_cmdline_device(struct device *dev, void *data)
{
struct platform_device *pdev = to_platform_device(dev);
struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
kfree(pdata->socket_path);
platform_device_unregister(pdev);
return 0;
}
static void vu_conn_broken(struct work_struct *wk)
{
struct virtio_uml_platform_data *pdata;
pdata = container_of(wk, struct virtio_uml_platform_data, conn_broken_wk);
vu_unregister_cmdline_device(&pdata->pdev->dev, NULL);
}
static int vu_cmdline_set(const char *device, const struct kernel_param *kp)
{
const char *ids = strchr(device, ':');
unsigned int virtio_device_id;
int processed, consumed, err;
char *socket_path;
struct virtio_uml_platform_data pdata, *ppdata;
struct platform_device *pdev;
if (!ids || ids == device)
return -EINVAL;
processed = sscanf(ids, ":%u%n:%d%n",
&virtio_device_id, &consumed,
&vu_cmdline_id, &consumed);
if (processed < 1 || ids[consumed])
return -EINVAL;
if (!vu_cmdline_parent_registered) {
err = device_register(&vu_cmdline_parent);
if (err) {
pr_err("Failed to register parent device!\n");
put_device(&vu_cmdline_parent);
return err;
}
vu_cmdline_parent_registered = true;
}
socket_path = kmemdup_nul(device, ids - device, GFP_KERNEL);
if (!socket_path)
return -ENOMEM;
pdata.virtio_device_id = (u32) virtio_device_id;
pdata.socket_path = socket_path;
pr_info("Registering device virtio-uml.%d id=%d at %s\n",
vu_cmdline_id, virtio_device_id, socket_path);
pdev = platform_device_register_data(&vu_cmdline_parent, "virtio-uml",
vu_cmdline_id++, &pdata,
sizeof(pdata));
err = PTR_ERR_OR_ZERO(pdev);
if (err)
goto free;
ppdata = pdev->dev.platform_data;
ppdata->pdev = pdev;
INIT_WORK(&ppdata->conn_broken_wk, vu_conn_broken);
return 0;
free:
kfree(socket_path);
return err;
}
static int vu_cmdline_get_device(struct device *dev, void *data)
{
struct platform_device *pdev = to_platform_device(dev);
struct virtio_uml_platform_data *pdata = pdev->dev.platform_data;
char *buffer = data;
unsigned int len = strlen(buffer);
snprintf(buffer + len, PAGE_SIZE - len, "%s:%d:%d\n",
pdata->socket_path, pdata->virtio_device_id, pdev->id);
return 0;
}
static int vu_cmdline_get(char *buffer, const struct kernel_param *kp)
{
buffer[0] = '\0';
if (vu_cmdline_parent_registered)
device_for_each_child(&vu_cmdline_parent, buffer,
vu_cmdline_get_device);
return strlen(buffer) + 1;
}
static const struct kernel_param_ops vu_cmdline_param_ops = {
.set = vu_cmdline_set,
.get = vu_cmdline_get,
};
device_param_cb(device, &vu_cmdline_param_ops, NULL, S_IRUSR);
__uml_help(vu_cmdline_param_ops,
"virtio_uml.device=<socket>:<virtio_id>[:<platform_id>]\n"
" Configure a virtio device over a vhost-user socket.\n"
" See virtio_ids.h for a list of possible virtio device id values.\n"
" Optionally use a specific platform_device id.\n\n"
);
static void vu_unregister_cmdline_devices(void)
{
if (vu_cmdline_parent_registered) {
device_for_each_child(&vu_cmdline_parent, NULL,
vu_unregister_cmdline_device);
device_unregister(&vu_cmdline_parent);
vu_cmdline_parent_registered = false;
}
}
/* Platform driver */
static const struct of_device_id virtio_uml_match[] = {
{ .compatible = "virtio,uml", },
{ }
};
MODULE_DEVICE_TABLE(of, virtio_uml_match);
static struct platform_driver virtio_uml_driver = {
.probe = virtio_uml_probe,
.remove = virtio_uml_remove,
.driver = {
.name = "virtio-uml",
.of_match_table = virtio_uml_match,
},
};
static int __init virtio_uml_init(void)
{
return platform_driver_register(&virtio_uml_driver);
}
static void __exit virtio_uml_exit(void)
{
platform_driver_unregister(&virtio_uml_driver);
vu_unregister_cmdline_devices();
}
module_init(virtio_uml_init);
module_exit(virtio_uml_exit);
__uml_exitcall(virtio_uml_exit);
MODULE_DESCRIPTION("UML driver for vhost-user virtio devices");
MODULE_LICENSE("GPL");