---
samples/vfio-mdev/mtty.c | 590 +++++++++++++++++++++++++++++++++++++++
1 file changed, 590 insertions(+)
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 245db52bedf2..69ba0281f9e0 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -29,6 +29,8 @@
#include <linux/serial.h>
#include <uapi/linux/serial_reg.h>
#include <linux/eventfd.h>
+#include <linux/anon_inodes.h>
+
/*
* #defines
*/
@@ -124,6 +126,29 @@ struct serial_port {
u8 intr_trigger_level; /* interrupt trigger level */
};
+struct mtty_data {
+ u64 magic;
+#define MTTY_MAGIC 0x7e9d09898c3e2c4e /* Nothing clever, just random */
+ u32 major_ver;
+#define MTTY_MAJOR_VER 1
+ u32 minor_ver;
+#define MTTY_MINOR_VER 0
+ u32 nr_ports;
+ u32 flags;
+ struct serial_port ports[2];
+};
+
+struct mdev_state;
+
+struct mtty_migration_file {
+ struct file *filp;
+ struct mutex lock;
+ struct mdev_state *mdev_state;
+ struct mtty_data data;
+ ssize_t filled_size;
+ u8 disabled:1;
+};
+
/* State of each mdev device */
struct mdev_state {
struct vfio_device vdev;
@@ -140,6 +165,12 @@ struct mdev_state {
struct mutex rxtx_lock;
struct vfio_device_info dev_info;
int nr_ports;
+ enum vfio_device_mig_state state;
+ struct mutex state_mutex;
+ struct mutex reset_mutex;
+ struct mtty_migration_file *saving_migf;
+ struct mtty_migration_file *resuming_migf;
+ u8 deferred_reset:1;
u8 intx_mask:1;
};
@@ -743,6 +774,543 @@ static ssize_t mdev_access(struct mdev_state *mdev_state, u8 *buf, size_t count,
return ret;
}
+static size_t mtty_data_size(struct mdev_state *mdev_state)
+{
+ return offsetof(struct mtty_data, ports) +
+ (mdev_state->nr_ports * sizeof(struct serial_port));
+}
+
+static void mtty_disable_file(struct mtty_migration_file *migf)
+{
+ mutex_lock(&migf->lock);
+ migf->disabled = true;
+ migf->filled_size = 0;
+ migf->filp->f_pos = 0;
+ mutex_unlock(&migf->lock);
+}
+
+static void mtty_disable_files(struct mdev_state *mdev_state)
+{
+ if (mdev_state->saving_migf) {
+ mtty_disable_file(mdev_state->saving_migf);
+ fput(mdev_state->saving_migf->filp);
+ mdev_state->saving_migf = NULL;
+ }
+
+ if (mdev_state->resuming_migf) {
+ mtty_disable_file(mdev_state->resuming_migf);
+ fput(mdev_state->resuming_migf->filp);
+ mdev_state->resuming_migf = NULL;
+ }
+}
+
+static void mtty_state_mutex_unlock(struct mdev_state *mdev_state)
+{
+again:
+ mutex_lock(&mdev_state->reset_mutex);
+ if (mdev_state->deferred_reset) {
+ mdev_state->deferred_reset = false;
+ mutex_unlock(&mdev_state->reset_mutex);
+ mdev_state->state = VFIO_DEVICE_STATE_RUNNING;
+ mtty_disable_files(mdev_state);
+ goto again;
+ }
+ mutex_unlock(&mdev_state->state_mutex);
+ mutex_unlock(&mdev_state->reset_mutex);
+}
+
+static int mtty_release_migf(struct inode *inode, struct file *filp)
+{
+ struct mtty_migration_file *migf = filp->private_data;
+
+ mtty_disable_file(migf);
+ mutex_destroy(&migf->lock);
+ kfree(migf);
+
+ return 0;
+}
+
+static long mtty_precopy_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct mtty_migration_file *migf = filp->private_data;
+ struct mdev_state *mdev_state = migf->mdev_state;
+ loff_t *pos = &filp->f_pos;
+ struct vfio_precopy_info info = {};
+ unsigned long minsz;
+ int ret;
+
+ if (cmd != VFIO_MIG_GET_PRECOPY_INFO)
+ return -ENOTTY;
+
+ minsz = offsetofend(struct vfio_precopy_info, dirty_bytes);
+
+ if (copy_from_user(&info, (void __user *)arg, minsz))
+ return -EFAULT;
+ if (info.argsz < minsz)
+ return -EINVAL;
+
+ mutex_lock(&mdev_state->state_mutex);
+ if (mdev_state->state != VFIO_DEVICE_STATE_PRE_COPY &&
+ mdev_state->state != VFIO_DEVICE_STATE_PRE_COPY_P2P) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ mutex_lock(&migf->lock);
+
+ if (migf->disabled) {
+ mutex_unlock(&migf->lock);
+ ret = -ENODEV;
+ goto unlock;
+ }
+
+ if (*pos > migf->filled_size) {
+ mutex_unlock(&migf->lock);
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ info.dirty_bytes = 0;
+ info.initial_bytes = migf->filled_size - *pos;
+ mutex_unlock(&migf->lock);
+
+ ret = copy_to_user((void __user *)arg, &info, minsz) ? -EFAULT : 0;
+unlock:
+ mtty_state_mutex_unlock(mdev_state);
+ return ret;
+}
+
+static ssize_t mtty_save_read(struct file *filp, char __user *buf,
+ size_t len, loff_t *pos)
+{
+ struct mtty_migration_file *migf = filp->private_data;
+ ssize_t ret = 0;
+
+ if (pos)
+ return -ESPIPE;
+
+ pos = &filp->f_pos;
+
+ mutex_lock(&migf->lock);
+
+ dev_dbg(migf->mdev_state->vdev.dev, "%s ask %zu\n", __func__, len);
+
+ if (migf->disabled) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ if (*pos > migf->filled_size) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ len = min_t(size_t, migf->filled_size - *pos, len);
+ if (len) {
+ if (copy_to_user(buf, (void *)&migf->data + *pos, len)) {
+ ret = -EFAULT;
+ goto out_unlock;
+ }
+ *pos += len;
+ ret = len;
+ }
+out_unlock:
+ dev_dbg(migf->mdev_state->vdev.dev, "%s read %zu\n", __func__, ret);
+ mutex_unlock(&migf->lock);
+ return ret;
+}
+
+static const struct file_operations mtty_save_fops = {
+ .owner = THIS_MODULE,
+ .read = mtty_save_read,
+ .unlocked_ioctl = mtty_precopy_ioctl,
+ .compat_ioctl = compat_ptr_ioctl,
+ .release = mtty_release_migf,
+ .llseek = no_llseek,
+};
+
+static void mtty_save_state(struct mdev_state *mdev_state)
+{
+ struct mtty_migration_file *migf = mdev_state->saving_migf;
+ int i;
+
+ mutex_lock(&migf->lock);
+ for (i = 0; i < mdev_state->nr_ports; i++) {
+ memcpy(&migf->data.ports[i],
+ &mdev_state->s[i], sizeof(struct serial_port));
+ migf->filled_size += sizeof(struct serial_port);
+ }
+ dev_dbg(mdev_state->vdev.dev,
+ "%s filled to %zu\n", __func__, migf->filled_size);
+ mutex_unlock(&migf->lock);
+}
+
+static int mtty_load_state(struct mdev_state *mdev_state)
+{
+ struct mtty_migration_file *migf = mdev_state->resuming_migf;
+ int i;
+
+ mutex_lock(&migf->lock);
+ /* magic and version already tested by resume write fn */
+ if (migf->filled_size < mtty_data_size(mdev_state)) {
+ dev_dbg(mdev_state->vdev.dev, "%s expected %zu, got %zu\n",
+ __func__, mtty_data_size(mdev_state),
+ migf->filled_size);
+ mutex_unlock(&migf->lock);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < mdev_state->nr_ports; i++)
+ memcpy(&mdev_state->s[i],
+ &migf->data.ports[i], sizeof(struct serial_port));
+
+ mutex_unlock(&migf->lock);
+ return 0;
+}
+
+static struct mtty_migration_file *
+mtty_save_device_data(struct mdev_state *mdev_state,
+ enum vfio_device_mig_state state)
+{
+ struct mtty_migration_file *migf = mdev_state->saving_migf;
+ struct mtty_migration_file *ret = NULL;
+
+ if (migf) {
+ if (state == VFIO_DEVICE_STATE_STOP_COPY)
+ goto fill_data;
+ return ret;
+ }
+
+ migf = kzalloc(sizeof(*migf), GFP_KERNEL_ACCOUNT);
+ if (!migf)
+ return ERR_PTR(-ENOMEM);
+
+ migf->filp = anon_inode_getfile("mtty_mig", &mtty_save_fops,
+ migf, O_RDONLY);
+ if (IS_ERR(migf->filp)) {
+ int rc = PTR_ERR(migf->filp);
+
+ kfree(migf);
+ return ERR_PTR(rc);
+ }
+
+ stream_open(migf->filp->f_inode, migf->filp);
+ mutex_init(&migf->lock);
+ migf->mdev_state = mdev_state;
+
+ migf->data.magic = MTTY_MAGIC;
+ migf->data.major_ver = MTTY_MAJOR_VER;
+ migf->data.minor_ver = MTTY_MINOR_VER;
+ migf->data.nr_ports = mdev_state->nr_ports;
+
+ migf->filled_size = offsetof(struct mtty_data, ports);
+
+ dev_dbg(mdev_state->vdev.dev, "%s filled header to %zu\n",
+ __func__, migf->filled_size);
+
+ ret = mdev_state->saving_migf = migf;
+
+fill_data:
+ if (state == VFIO_DEVICE_STATE_STOP_COPY)
+ mtty_save_state(mdev_state);
+
+ return ret;
+}
+
+static ssize_t mtty_resume_write(struct file *filp, const char __user *buf,
+ size_t len, loff_t *pos)
+{
+ struct mtty_migration_file *migf = filp->private_data;
+ struct mdev_state *mdev_state = migf->mdev_state;
+ loff_t requested_length;
+ ssize_t ret = 0;
+
+ if (pos)
+ return -ESPIPE;
+
+ pos = &filp->f_pos;
+
+ if (*pos < 0 ||
+ check_add_overflow((loff_t)len, *pos, &requested_length))
+ return -EINVAL;
+
+ if (requested_length > mtty_data_size(mdev_state))
+ return -ENOMEM;
+
+ mutex_lock(&migf->lock);
+
+ if (migf->disabled) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ if (copy_from_user((void *)&migf->data + *pos, buf, len)) {
+ ret = -EFAULT;
+ goto out_unlock;
+ }
+
+ *pos += len;
+ ret = len;
+
+ dev_dbg(migf->mdev_state->vdev.dev, "%s received %zu, total %zu\n",
+ __func__, len, migf->filled_size + len);
+
+ if (migf->filled_size < offsetof(struct mtty_data, ports) &&
+ migf->filled_size + len >= offsetof(struct mtty_data, ports)) {
+ if (migf->data.magic != MTTY_MAGIC || migf->data.flags ||
+ migf->data.major_ver != MTTY_MAJOR_VER ||
+ migf->data.minor_ver != MTTY_MINOR_VER ||
+ migf->data.nr_ports != mdev_state->nr_ports) {
+ dev_dbg(migf->mdev_state->vdev.dev,
+ "%s failed validation\n", __func__);
+ ret = -EFAULT;
+ } else {
+ dev_dbg(migf->mdev_state->vdev.dev,
+ "%s header validated\n", __func__);
+ }
+ }
+
+ migf->filled_size += len;
+
+out_unlock:
+ mutex_unlock(&migf->lock);
+ return ret;
+}
+
+static const struct file_operations mtty_resume_fops = {
+ .owner = THIS_MODULE,
+ .write = mtty_resume_write,
+ .release = mtty_release_migf,
+ .llseek = no_llseek,
+};
+
+static struct mtty_migration_file *
+mtty_resume_device_data(struct mdev_state *mdev_state)
+{
+ struct mtty_migration_file *migf;
+ int ret;
+
+ migf = kzalloc(sizeof(*migf), GFP_KERNEL_ACCOUNT);
+ if (!migf)
+ return ERR_PTR(-ENOMEM);
+
+ migf->filp = anon_inode_getfile("mtty_mig", &mtty_resume_fops,
+ migf, O_WRONLY);
+ if (IS_ERR(migf->filp)) {
+ ret = PTR_ERR(migf->filp);
+ kfree(migf);
+ return ERR_PTR(ret);
+ }
+
+ stream_open(migf->filp->f_inode, migf->filp);
+ mutex_init(&migf->lock);
+ migf->mdev_state = mdev_state;
+
+ mdev_state->resuming_migf = migf;
+
+ return migf;
+}
+
+static struct file *mtty_step_state(struct mdev_state *mdev_state,
+ enum vfio_device_mig_state new)
+{
+ enum vfio_device_mig_state cur = mdev_state->state;
+
+ dev_dbg(mdev_state->vdev.dev, "%s: %d -> %d\n", __func__, cur, new);
+
+ /*
+ * The following state transitions are no-op considering
+ * mtty does not do DMA nor require any explicit start/stop.
+ *
+ * RUNNING -> RUNNING_P2P
+ * RUNNING_P2P -> RUNNING
+ * RUNNING_P2P -> STOP
+ * PRE_COPY -> PRE_COPY_P2P
+ * PRE_COPY_P2P -> PRE_COPY
+ * STOP -> RUNNING_P2P
+ */
+ if ((cur == VFIO_DEVICE_STATE_RUNNING &&
+ new == VFIO_DEVICE_STATE_RUNNING_P2P) ||
+ (cur == VFIO_DEVICE_STATE_RUNNING_P2P &&
+ (new == VFIO_DEVICE_STATE_RUNNING ||
+ new == VFIO_DEVICE_STATE_STOP)) ||
+ (cur == VFIO_DEVICE_STATE_PRE_COPY &&
+ new == VFIO_DEVICE_STATE_PRE_COPY_P2P) ||
+ (cur == VFIO_DEVICE_STATE_PRE_COPY_P2P &&
+ new == VFIO_DEVICE_STATE_PRE_COPY) ||
+ (cur == VFIO_DEVICE_STATE_STOP &&
+ new == VFIO_DEVICE_STATE_RUNNING_P2P))
+ return NULL;
+
+ /*
+ * The following state transitions simply close migration files,
+ * with the exception of RESUMING -> STOP, which needs to load
+ * the state first.
+ *
+ * RESUMING -> STOP
+ * PRE_COPY -> RUNNING
+ * PRE_COPY_P2P -> RUNNING_P2P
+ * STOP_COPY -> STOP
+ */
+ if (cur == VFIO_DEVICE_STATE_RESUMING &&
+ new == VFIO_DEVICE_STATE_STOP) {
+ int ret;
+
+ ret = mtty_load_state(mdev_state);
+ if (ret)
+ return ERR_PTR(ret);
+ mtty_disable_files(mdev_state);
+ return NULL;
+ }
+
+ if ((cur == VFIO_DEVICE_STATE_PRE_COPY &&
+ new == VFIO_DEVICE_STATE_RUNNING) ||
+ (cur == VFIO_DEVICE_STATE_PRE_COPY_P2P &&
+ new == VFIO_DEVICE_STATE_RUNNING_P2P) ||
+ (cur == VFIO_DEVICE_STATE_STOP_COPY &&
+ new == VFIO_DEVICE_STATE_STOP)) {
+ mtty_disable_files(mdev_state);
+ return NULL;
+ }
+
+ /*
+ * The following state transitions return migration files.
+ *
+ * RUNNING -> PRE_COPY
+ * RUNNING_P2P -> PRE_COPY_P2P
+ * STOP -> STOP_COPY
+ * STOP -> RESUMING
+ * PRE_COPY_P2P -> STOP_COPY
+ */
+ if ((cur == VFIO_DEVICE_STATE_RUNNING &&
+ new == VFIO_DEVICE_STATE_PRE_COPY) ||
+ (cur == VFIO_DEVICE_STATE_RUNNING_P2P &&
+ new == VFIO_DEVICE_STATE_PRE_COPY_P2P) ||
+ (cur == VFIO_DEVICE_STATE_STOP &&
+ new == VFIO_DEVICE_STATE_STOP_COPY) ||
+ (cur == VFIO_DEVICE_STATE_PRE_COPY_P2P &&
+ new == VFIO_DEVICE_STATE_STOP_COPY)) {
+ struct mtty_migration_file *migf;
+
+ migf = mtty_save_device_data(mdev_state, new);
+ if (IS_ERR(migf))
+ return ERR_CAST(migf);
+
+ if (migf) {
+ get_file(migf->filp);
+
+ return migf->filp;
+ }
+ return NULL;
+ }
+
+ if (cur == VFIO_DEVICE_STATE_STOP &&
+ new == VFIO_DEVICE_STATE_RESUMING) {
+ struct mtty_migration_file *migf;
+
+ migf = mtty_resume_device_data(mdev_state);
+ if (IS_ERR(migf))
+ return ERR_CAST(migf);
+
+ get_file(migf->filp);
+
+ return migf->filp;
+ }
+
+ /* vfio_mig_get_next_state() does not use arcs other than the above */
+ WARN_ON(true);
+ return ERR_PTR(-EINVAL);
+}
+
+static struct file *mtty_set_state(struct vfio_device *vdev,
+ enum vfio_device_mig_state new_state)
+{
+ struct mdev_state *mdev_state =
+ container_of(vdev, struct mdev_state, vdev);
+ struct file *ret = NULL;
+
+ dev_dbg(vdev->dev, "%s -> %d\n", __func__, new_state);
+
+ mutex_lock(&mdev_state->state_mutex);
+ while (mdev_state->state != new_state) {
+ enum vfio_device_mig_state next_state;
+ int rc = vfio_mig_get_next_state(vdev, mdev_state->state,
+ new_state, &next_state);
+ if (rc) {
+ ret = ERR_PTR(rc);
+ break;
+ }
+
+ ret = mtty_step_state(mdev_state, next_state);
+ if (IS_ERR(ret))
+ break;
+
+ mdev_state->state = next_state;
+
+ if (WARN_ON(ret && new_state != next_state)) {
+ fput(ret);
+ ret = ERR_PTR(-EINVAL);
+ break;
+ }
+ }
+ mtty_state_mutex_unlock(mdev_state);
+ return ret;
+}
+
+static int mtty_get_state(struct vfio_device *vdev,
+ enum vfio_device_mig_state *current_state)
+{
+ struct mdev_state *mdev_state =
+ container_of(vdev, struct mdev_state, vdev);
+
+ mutex_lock(&mdev_state->state_mutex);
+ *current_state = mdev_state->state;
+ mtty_state_mutex_unlock(mdev_state);
+ return 0;
+}
+
+static int mtty_get_data_size(struct vfio_device *vdev,
+ unsigned long *stop_copy_length)
+{
+ struct mdev_state *mdev_state =
+ container_of(vdev, struct mdev_state, vdev);
+
+ *stop_copy_length = mtty_data_size(mdev_state);
+ return 0;
+}
+
+static const struct vfio_migration_ops mtty_migration_ops = {
+ .migration_set_state = mtty_set_state,
+ .migration_get_state = mtty_get_state,
+ .migration_get_data_size = mtty_get_data_size,
+};
+
+static int mtty_log_start(struct vfio_device *vdev,
+ struct rb_root_cached *ranges,
+ u32 nnodes, u64 *page_size)
+{
+ return 0;
+}
+
+static int mtty_log_stop(struct vfio_device *vdev)
+{
+ return 0;
+}
+
+static int mtty_log_read_and_clear(struct vfio_device *vdev,
+ unsigned long iova, unsigned long length,
+ struct iova_bitmap *dirty)
+{
+ return 0;
+}
+
+static const struct vfio_log_ops mtty_log_ops = {
+ .log_start = mtty_log_start,
+ .log_stop = mtty_log_stop,
+ .log_read_and_clear = mtty_log_read_and_clear,
+};
+
static int mtty_init_dev(struct vfio_device *vdev)
{
struct mdev_state *mdev_state =
@@ -775,6 +1343,16 @@ static int mtty_init_dev(struct vfio_device *vdev)
mutex_init(&mdev_state->ops_lock);
mdev_state->mdev = mdev;
mtty_create_config_space(mdev_state);
+
+ mutex_init(&mdev_state->state_mutex);
+ mutex_init(&mdev_state->reset_mutex);
+ vdev->migration_flags = VFIO_MIGRATION_STOP_COPY |
+ VFIO_MIGRATION_P2P |
+ VFIO_MIGRATION_PRE_COPY;
+ vdev->mig_ops = &mtty_migration_ops;
+ vdev->log_ops = &mtty_log_ops;
+ mdev_state->state = VFIO_DEVICE_STATE_RUNNING;
+
return 0;
err_nr_ports:
@@ -808,6 +1386,8 @@ static void mtty_release_dev(struct vfio_device *vdev)
struct mdev_state *mdev_state =
container_of(vdev, struct mdev_state, vdev);
+ mutex_destroy(&mdev_state->reset_mutex);
+ mutex_destroy(&mdev_state->state_mutex);
atomic_add(mdev_state->nr_ports, &mdev_avail_ports);
kfree(mdev_state->vconfig);
}
@@ -824,6 +1404,15 @@ static int mtty_reset(struct mdev_state *mdev_state)
{
pr_info("%s: called\n", __func__);
+ mutex_lock(&mdev_state->reset_mutex);
+ mdev_state->deferred_reset = true;
+ if (!mutex_trylock(&mdev_state->state_mutex)) {
+ mutex_unlock(&mdev_state->reset_mutex);
+ return 0;
+ }
+ mutex_unlock(&mdev_state->reset_mutex);
+ mtty_state_mutex_unlock(mdev_state);
+
return 0;
}
@@ -1350,6 +1939,7 @@ static void mtty_close(struct vfio_device *vdev)
struct mdev_state *mdev_state =
container_of(vdev, struct mdev_state, vdev);
+ mtty_disable_files(mdev_state);
mtty_disable_intx(mdev_state);
mtty_disable_msi(mdev_state);
}
