On 2017-01-19 21:11, Ralf Ramsauer wrote:
> Signed-off-by: Ralf Ramsauer <[email protected]>
> ---
> Documentation/debug-output.md | 8 +++-
> driver/main.c | 97
> +++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 104 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/debug-output.md b/Documentation/debug-output.md
> index 1c11ca180a..5d0610a154 100644
> --- a/Documentation/debug-output.md
> +++ b/Documentation/debug-output.md
> @@ -89,7 +89,13 @@ Hypervisor Console via sysfs
>
> If the debug console of root cell has the flag JAILHOUSE_CON2_TYPE_ROOTPAGE
> set, the hypervisor console is available through
> -/sys/devices/jailhouse/console.
> +/sys/devices/jailhouse/console. Continuous reading of the hypervisor console
> +is available through /dev/jailhouse.
> +
> +Example
> +```
> +cat /dev/jailhouse
> +```
>
> Inmates
> -------
> diff --git a/driver/main.c b/driver/main.c
> index 2a86842448..4eade5724d 100644
> --- a/driver/main.c
> +++ b/driver/main.c
> @@ -71,6 +71,10 @@ MODULE_FIRMWARE(JAILHOUSE_FW_NAME);
> #endif
> MODULE_VERSION(JAILHOUSE_VERSION);
>
> +struct console_userdata {
How about "console_state"?
> + unsigned int head;
> +};
> +
> DEFINE_MUTEX(jailhouse_lock);
> bool jailhouse_enabled;
>
> @@ -616,11 +620,104 @@ static long jailhouse_ioctl(struct file *file,
> unsigned int ioctl,
> return err;
> }
>
> +static int jailhouse_console_open(struct inode *inode, struct file *file)
> +{
> + struct console_userdata *user;
> +
> + user = kzalloc(sizeof(struct console_userdata), GFP_KERNEL);
> + if (!user)
> + return -ENOMEM;
> +
> + file->private_data = user;
> +
> + return 0;
> +}
> +
> +static int jailhouse_console_release(struct inode *inode, struct file *file)
> +{
> + struct console_userdata *user = file->private_data;
> +
> + kfree(user);
> +
> + return 0;
> +}
> +
> +static ssize_t jailhouse_console_read(struct file *file, char __user *out,
> + size_t size, loff_t *off)
> +{
> + struct console_userdata *user = file->private_data;
> + char *content;
> + unsigned int miss;
> + int ret;
> +
> + content = kmalloc(sizeof(console_page->content), GFP_KERNEL);
> + if (content == NULL)
> + return -ENOMEM;
> +
> + /* wait for new data */
> + while (1) {
> + if (mutex_lock_interruptible(&jailhouse_lock) != 0) {
> + ret = -EINTR;
> + goto console_free_out;
> + }
> +
> + ret = jailhouse_console_page_delta(content, user->head, &miss);
> +
> + mutex_unlock(&jailhouse_lock);
> +
> + if ((!ret || ret == -EAGAIN) && file->f_flags & O_NONBLOCK)
> + goto console_free_out;
> +
> + if (ret == -EAGAIN)
> + /* Reset the user head, if jailhouse is not enabled. We
> + * have to do this, as jailhouse might be reenabled and
> + * the file handle was kept open in the meanwhile */
> + user->head = 0;
> + else if (ret < 0)
> + goto console_free_out;
> + else if (ret)
> + break;
> +
> + schedule_timeout_uninterruptible(HZ / 10);
> + if (signal_pending(current)) {
> + ret = -EINTR;
> + goto console_free_out;
> + }
> + }
> +
> + if (miss) {
> + /* If we missed anything, warn user. We will dump the actual
> + * content in the next call. */
> + ret = snprintf(content, sizeof(console_page->content),
> + "<NOTE: missing %u byte console log>\n",
"missed %u bytes of console log"
> + miss);
> + user->head += miss;
> + if (size < ret)
> + ret = size;
Why is user->head only update by "miss" here? ...
> + } else {
> + if (size < ret)
> + ret = size;
> + user->head += ret;
...And shouldn't the last line be pulled out and executed
unconditionally? Actually, that would allow to pull the "if size < ret"
as well.
> + }
> +
> + if (copy_to_user(out, content, ret))
> + ret = -EFAULT;
> +
> +console_free_out:
> + set_current_state(TASK_RUNNING);
> + kfree(content);
> + return ret;
> +}
> +
> +
> static const struct file_operations jailhouse_fops = {
> .owner = THIS_MODULE,
> .unlocked_ioctl = jailhouse_ioctl,
> .compat_ioctl = jailhouse_ioctl,
> .llseek = noop_llseek,
> + .open = jailhouse_console_open,
> + .release = jailhouse_console_release,
> + .read = jailhouse_console_read,
> };
>
> static struct miscdevice jailhouse_misc_dev = {
>
Jan
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