From: Steffen Eiden <seiden@xxxxxxxxxxxxx> 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> Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230615100533.3996107-3-seiden@xxxxxxxxxxxxx Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx> Message-Id: <20230615100533.3996107-3-seiden@xxxxxxxxxxxxx> --- arch/s390/include/uapi/asm/uvdevice.h | 42 ++++++++++++++- drivers/s390/char/Kconfig | 2 +- drivers/s390/char/uvdevice.c | 77 ++++++++++++++++++++++++--- 3 files changed, 112 insertions(+), 9 deletions(-) diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h index 10a5ac918e02..9d9b684836c2 100644 --- a/arch/s390/include/uapi/asm/uvdevice.h +++ b/arch/s390/include/uapi/asm/uvdevice.h @@ -32,6 +32,33 @@ 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 +73,19 @@ 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/Kconfig b/drivers/s390/char/Kconfig index 80c4e5101c97..8a03af5ee5b3 100644 --- a/drivers/s390/char/Kconfig +++ b/drivers/s390/char/Kconfig @@ -96,7 +96,7 @@ config SCLP_OFB config S390_UV_UAPI def_tristate m prompt "Ultravisor userspace API" - depends on S390 + depends on S390 && (KVM || PROTECTED_VIRTUALIZATION_GUEST) help Selecting exposes parts of the UV interface to userspace by providing a misc character device at /dev/uv. diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c index 1d40457c7b10..7d7866be389b 100644 --- a/drivers/s390/char/uvdevice.c +++ b/drivers/s390/char/uvdevice.c @@ -32,6 +32,52 @@ #include <asm/uvdevice.h> #include <asm/uv.h> +#define BIT_UVIO_INTERNAL U32_MAX +/* Mapping from IOCTL-nr to UVC-bit */ +static const u32 ioctl_nr_to_uvc_bit[] __initconst = { + [UVIO_IOCTL_UVDEV_INFO_NR] = BIT_UVIO_INTERNAL, + [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(unsigned long *supp_uv_cmds) +{ + int i; + + for (i = 0; i < UVIO_IOCTL_NUM_IOCTLS; i++) { + if (ioctl_nr_to_uvc_bit[i] == BIT_UVIO_INTERNAL) + continue; + if (!test_bit_inv(ioctl_nr_to_uvc_bit[i], uv_info.inst_calls_list)) + continue; + __set_bit(i, supp_uv_cmds); + } +} + +/** + * uvio_uvdev_info() - get information about the uvdevice + * + * @uv_ioctl: ioctl control block + * + * Lists all IOCTLs that are supported 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; - switch (cmd) { - case UVIO_IOCTL_ATT: - ret = uvio_copy_and_check_ioctl(&uv_ioctl, argp); - if (ret) - return ret; + nr = uvio_copy_and_check_ioctl(&uv_ioctl, argp, cmd); + if (nr < 0) + return nr; + + 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((unsigned long *)&uvdev_info.supp_uv_cmds); return misc_register(&uvio_dev_miscdev); } -- 2.41.0
