Add an IOCTL that allows userspace to find out which IOCTLs the uvdevice
supports without trial and error.
Explicitly expose the IOCTL nr for the request types.
Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
arch/s390/include/uapi/asm/uvdevice.h | 45 +++++++++++++++-
drivers/s390/char/uvdevice.c | 77 ++++++++++++++++++++++++---
2 files changed, 114 insertions(+), 8 deletions(-)
diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
index 10a5ac918e02..ed58979b8438 100644
--- a/arch/s390/include/uapi/asm/uvdevice.h
+++ b/arch/s390/include/uapi/asm/uvdevice.h
@@ -32,6 +32,36 @@ struct uvio_attest {
__u16 reserved136; /* 0x0136 */
};
+/**
+ * uvio_uvdev_info - Information of supported functions
+ *
+ * @supp_uvio_cmds - supported IOCTLs by this device
+ * @supp_uv_cmds - supported UVCs corresponding to the IOCTL
+ *
+ * UVIO request to get information about supported request types by this
+ * uvdevice and the Ultravisor.
+ * Everything is output. Bits are in LSB0 ordering.
+ * If the bit is set in both, @supp_uvio_cmds and @supp_uv_cmds,
+ * the uvdevice and the Ultravisor support that call.
+ *
+ * Note that bit 0 (UVIO_IOCTL_UVDEV_INFO_NR) is always zero for `supp_uv_cmds`
+ * as there is no corresponding UV-call.
+ */
+struct uvio_uvdev_info {
+ /*
+ * If bit `n` is set, this device supports the IOCTL with nr `n`.
+ */
+ __u64 supp_uvio_cmds;
+ /*
+ * If bit `n` is set, the Ultravisor(UV) supports the UV-call
+ * corresponding to the IOCTL with nr `n` in the calling contextx
+ * (host or guest).
+ * The value is only valid if the corresponding bit in @supp_uvio_cmds
+ * is set as well.
+ */
+ __u64 supp_uv_cmds;
+};
+
/*
* The following max values define an upper length for the IOCTL in/out buffers.
* However, they do not represent the maximum the Ultravisor allows which is
@@ -46,6 +76,19 @@ struct uvio_attest {
#define UVIO_DEVICE_NAME "uv"
#define UVIO_TYPE_UVC 'u'
-#define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
+enum UVIO_IOCTL_NR {
+ UVIO_IOCTL_UVDEV_INFO_NR = 0x00,
+ UVIO_IOCTL_ATT_NR,
+ /* must be the last entry */
+ UVIO_IOCTL_NUM_IOCTLS
+};
+
+#define UVIO_IOCTL(nr) _IOWR(UVIO_TYPE_UVC, nr, struct uvio_ioctl_cb)
+#define UVIO_IOCTL_UVDEV_INFO UVIO_IOCTL(UVIO_IOCTL_UVDEV_INFO_NR)
+#define UVIO_IOCTL_ATT UVIO_IOCTL(UVIO_IOCTL_ATT_NR)
+
+#define UVIO_SUPP_CALL(nr) (1ULL << (nr))
+#define UVIO_SUPP_UDEV_INFO UVIO_SUPP_CALL(UVIO_IOCTL_UDEV_INFO_NR)
+#define UVIO_SUPP_ATT UVIO_SUPP_CALL(UVIO_IOCTL_ATT_NR)
#endif /* __S390_ASM_UVDEVICE_H */
diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
index 1d40457c7b10..27f5bf1cf27a 100644
--- a/drivers/s390/char/uvdevice.c
+++ b/drivers/s390/char/uvdevice.c
@@ -20,6 +20,7 @@
* channel for userspace to the Ultravisor.
*/
+#include "asm-generic/ioctl.h"
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
@@ -32,6 +33,51 @@
#include <asm/uvdevice.h>
#include <asm/uv.h>
+/* Mapping from IOCTL-nr to UVC-bit */
+static const u64 ioctl_nr_to_uvc_bit[] __initconst = {
+ [UVIO_IOCTL_UVDEV_INFO_NR] = -1UL,
+ [UVIO_IOCTL_ATT_NR] = BIT_UVC_CMD_RETR_ATTEST,
+};
+
+static_assert(ARRAY_SIZE(ioctl_nr_to_uvc_bit) == UVIO_IOCTL_NUM_IOCTLS);
+
+static struct uvio_uvdev_info uvdev_info = {
+ .supp_uvio_cmds = GENMASK_ULL(UVIO_IOCTL_NUM_IOCTLS - 1, 0),
+};
+
+static void __init set_supp_uv_cmds(struct uvio_uvdev_info *info)
+{
+ int i;
+
+ for (i = 0; i < UVIO_IOCTL_NUM_IOCTLS; i++) {
+ if (ioctl_nr_to_uvc_bit[i] == -1UL)
+ continue;
+ if (!test_bit_inv(ioctl_nr_to_uvc_bit[i], uv_info.inst_calls_list))
+ continue;
+ set_bit(i, (unsigned long *)&info->supp_uv_cmds);
+ }
+}
+
+/**
+ * uvio_uvdev_info() - get information about the uvdevice
+ *
+ * @uv_ioctl: ioctl control block
+ *
+ * Lists all supported IOCTLs by this uvdevice
+ */
+static int uvio_uvdev_info(struct uvio_ioctl_cb *uv_ioctl)
+{
+ void __user *user_buf_arg = (void __user *)uv_ioctl->argument_addr;
+
+ if (uv_ioctl->argument_len < sizeof(uvdev_info))
+ return -EINVAL;
+ if (copy_to_user(user_buf_arg, &uvdev_info, sizeof(uvdev_info)))
+ return -EFAULT;
+
+ uv_ioctl->uv_rc = UVC_RC_EXECUTED;
+ return 0;
+}
+
static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
{
@@ -185,8 +231,19 @@ static int uvio_attestation(struct uvio_ioctl_cb *uv_ioctl)
return ret;
}
-static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp)
+static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp,
+ unsigned long cmd)
{
+ u8 nr = _IOC_NR(cmd);
+
+ if (_IOC_DIR(cmd) != (_IOC_READ | _IOC_WRITE))
+ return -ENOIOCTLCMD;
+ if (_IOC_TYPE(cmd) != UVIO_TYPE_UVC)
+ return -ENOIOCTLCMD;
+ if (nr >= UVIO_IOCTL_NUM_IOCTLS)
+ return -ENOIOCTLCMD;
+ if (_IOC_SIZE(cmd) != sizeof(*ioctl))
+ return -ENOIOCTLCMD;
if (copy_from_user(ioctl, argp, sizeof(*ioctl)))
return -EFAULT;
if (ioctl->flags != 0)
@@ -194,7 +251,7 @@ static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *a
if (memchr_inv(ioctl->reserved14, 0, sizeof(ioctl->reserved14)))
return -EINVAL;
- return 0;
+ return nr;
}
/*
@@ -205,12 +262,17 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
void __user *argp = (void __user *)arg;
struct uvio_ioctl_cb uv_ioctl = { };
long ret;
+ int nr;
+
+ nr = uvio_copy_and_check_ioctl(&uv_ioctl, argp, cmd);
+ if (nr < 0)
+ return nr;
- switch (cmd) {
- case UVIO_IOCTL_ATT:
- ret = uvio_copy_and_check_ioctl(&uv_ioctl, argp);
- if (ret)
- return ret;
+ switch (nr) {
+ case UVIO_IOCTL_UVDEV_INFO_NR:
+ ret = uvio_uvdev_info(&uv_ioctl);
+ break;
+ case UVIO_IOCTL_ATT_NR:
ret = uvio_attestation(&uv_ioctl);
break;
default:
@@ -245,6 +307,7 @@ static void __exit uvio_dev_exit(void)
static int __init uvio_dev_init(void)
{
+ set_supp_uv_cmds(&uvdev_info);
return misc_register(&uvio_dev_miscdev);
}
--
2.40.1
