On Fri, 12 May 2023 11:31:51 +0200
Steffen Eiden <seiden@xxxxxxxxxxxxx> wrote:
> Userspace can call the List Secrets Ultravisor Call
> using IOCTLs on the uvdevice.
> During the handling of the new IOCTL nr the uvdevice will do some sanity
> checks first. Then, perform the Ultravisor command, and copy the answer
> to userspace.
> If the List Secrets UV facility is not present, UV will return
> invalid command rc. This won't be fenced in the driver and does not
> result in a negative return value. This is also true for any other
> possible error code the UV can return.
>
> Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
> ---
[...]
> diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
> index ba3e60dc4ba8..5fcd719047ab 100644
> --- a/drivers/s390/char/uvdevice.c
> +++ b/drivers/s390/char/uvdevice.c
> @@ -38,6 +38,7 @@ static const u64 ioctl_nr_to_uvc_bit[] __initconst = {
> [UVIO_IOCTL_UVDEV_INFO_NR] = -1UL,
> [UVIO_IOCTL_ATT_NR] = BIT_UVC_CMD_RETR_ATTEST,
> [UVIO_IOCTL_ADD_SECRET_NR] = BIT_UVC_CMD_ADD_SECRET,
> + [UVIO_IOCTL_LIST_SECRETS_NR] = BIT_UVC_CMD_LIST_SECRETS,
> };
>
> static_assert(ARRAY_SIZE(ioctl_nr_to_uvc_bit) == UVIO_IOCTL_NUM_IOCTLS);
> @@ -286,6 +287,57 @@ static int uvio_add_secret(struct uvio_ioctl_cb *uv_ioctl)
> return ret;
> }
>
> +/** uvio_list_secrets() - perform a List Secret UVC
> + *
> + * @uv_ioctl: ioctl control block
> + *
> + * uvio_list_secrets() performs the List Secret Ultravisor Call.
> + * It verifies that the given userspace argument address is valid and its size
> + * is sane. Every other check is made by the Ultravisor (UV) and won't result
> + * in a negative return value. It builds the request, performs the UV-call,
> + * and copies the result to userspace.
> + *
> + * The argument specifies the location for the result of the UV-Call.
> + *
> + * If the List Secrets UV facility is not present,
> + * UV will return invalid command rc. This won't be fenced in the driver
> + * and does not result in a negative return value.
> + *
> + * Context: might sleep
> + *
> + * Return: 0 on success or a negative error code on error.
> + */
> +static int uvio_list_secrets(struct uvio_ioctl_cb *uv_ioctl)
> +{
> + void __user *user_buf_arg = (void __user *)uv_ioctl->argument_addr;
> + struct uv_cb_guest_addr uvcb = {
> + .header.len = sizeof(uvcb),
> + .header.cmd = UVC_CMD_LIST_SECRETS,
> + };
> + void *secrets = NULL;
> + int ret;
> +
> + if (uv_ioctl->argument_len != UVIO_LIST_SECRETS_LEN)
> + return -EINVAL;
> +
> + secrets = kvzalloc(uv_ioctl->argument_len, GFP_KERNEL);
> + if (!secrets)
> + return -ENOMEM;
> +
> + uvcb.addr = (u64)secrets;
I think you need virt_to_phys()
> + uv_call_sched(0, (u64)&uvcb);
> + uv_ioctl->uv_rc = uvcb.header.rc;
> + uv_ioctl->uv_rrc = uvcb.header.rrc;
> +
> + if (copy_to_user(user_buf_arg, secrets, uv_ioctl->argument_len))
> + ret = -EFAULT;
> + else
> + ret = 0;
> +
> + kvfree(secrets);
> + return ret;
> +}
> +
> static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp,
> unsigned long cmd)
> {
> @@ -333,6 +385,9 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> case UVIO_IOCTL_ADD_SECRET_NR:
> ret = uvio_add_secret(&uv_ioctl);
> break;
> + case UVIO_IOCTL_LIST_SECRETS_NR:
> + ret = uvio_list_secrets(&uv_ioctl);
> + break;
> default:
> ret = -ENOIOCTLCMD;
> break;
