On 5/19/23 11:37, Steffen Eiden wrote:
Userspace can call the Add Secret Ultravisor Call
using IOCTLs on the uvdevice.
During the handling of the new IOCTL nr the uvdevice will do some sanity
checks first. Then, copy the request data to kernel space, perform the
Ultravisor command, and copy the return codes to userspace.
If the Add Secret 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>
---
arch/s390/include/asm/uv.h | 14 +++++++
arch/s390/include/uapi/asm/uvdevice.h | 4 ++
drivers/s390/char/uvdevice.c | 58 +++++++++++++++++++++++++++
3 files changed, 76 insertions(+)
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 28a9ad57b6f1..a7dff64e1e24 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -58,6 +58,7 @@
#define UVC_CMD_SET_SHARED_ACCESS 0x1000
#define UVC_CMD_REMOVE_SHARED_ACCESS 0x1001
#define UVC_CMD_RETR_ATTEST 0x1020
+#define UVC_CMD_ADD_SECRET 0x1031
/* Bits in installed uv calls */
enum uv_cmds_inst {
@@ -88,6 +89,7 @@ enum uv_cmds_inst {
BIT_UVC_CMD_DUMP_CPU = 26,
BIT_UVC_CMD_DUMP_COMPLETE = 27,
BIT_UVC_CMD_RETR_ATTEST = 28,
+ BIT_UVC_CMD_ADD_SECRET = 29,
};
enum uv_feat_ind {
@@ -292,6 +294,18 @@ struct uv_cb_dump_complete {
u64 reserved30[5];
} __packed __aligned(8);
+/*
+ * A common call for pv guests that contains a single address
control block struct
+ * Examples:
+ * Add Secret
+ */
+struct uv_cb_guest_addr {
+ struct uv_cb_header header;
+ u64 reserved08[3];
+ u64 addr;
+ u64 reserved28[4];
+} __packed __aligned(8);
+
[...]
+static int uvio_add_secret(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_ADD_SECRET,
+ };
+ void *asrcb = NULL;
+ int ret;
+
+ if (uv_ioctl->argument_len > UVIO_ADD_SECRET_MAX_LEN)
+ return -EINVAL;
+ if (uv_ioctl->argument_len == 0)
+ return -EINVAL;
+
+ asrcb = kvzalloc(uv_ioctl->argument_len, GFP_KERNEL);
+ if (!asrcb)
+ return -EINVAL;
-ENOMEM
+
+ ret = -EFAULT;
+ if (copy_from_user(asrcb, user_buf_arg, uv_ioctl->argument_len))
+ goto out;
+
+ ret = 0;
+ uvcb.addr = (u64)asrcb;
+ uv_call_sched(0, (u64)&uvcb);
+ uv_ioctl->uv_rc = uvcb.header.rc;
+ uv_ioctl->uv_rrc = uvcb.header.rrc;
+
+out:
+ kvfree(asrcb);
+ return ret;
+}
+
static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp,
unsigned long cmd)
{
@@ -275,6 +330,9 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
case UVIO_IOCTL_ATT_NR:
ret = uvio_attestation(&uv_ioctl);
break;
+ case UVIO_IOCTL_ADD_SECRET_NR:
+ ret = uvio_add_secret(&uv_ioctl);
+ break;
default:
ret = -ENOIOCTLCMD;
break;
