[PATCH v3 0/4] s390: Ultravisor device

[PATCH v3 0/4] s390: Ultravisor device

[Steffen Eiden]

This series adds an Ultravisor(UV) device letting the userspace send some
Ultravisor calls to the UV. Currently two calls are supported.
Query Ultravisor Information (QUI) and
Receive Attestation Measurement (Attest[ation]).

The UV device is implemented as a miscdevice accepting only IOCTLs.
The IOCTL cmd specifies the UV call and the IOCTL arg the request
and response data depending on the UV call.
The device driver writes the UV response in the ioctl argument data.

The 'uvdevice' does no checks on the request beside faulty userspace
addresses, if sizes are in a sane range before allocating in kernel space,
and other tests that prevent the system from corruption.
Especially, no checks are made, that will be performed by the UV anyway
(E.g. 'invalid command' in case of attestation on unsupported hardware).
These errors are reported back to Userspace using the UV return code
field.

The first two patches introduce the new device as a module configured to be
compiled directly into the kernel (y) similar to the s390 SCLP and CHSH
miscdevice modules. Patch 3&4 introduce Kselftests which verify error
paths of the ioctl.

v2->v3:
   The main change is that QUI is now introduced after Attestation as we
   might not want pick it. Also the Kselftest patch is splitted into
   Attestation and QUI so that they can be picked without requiring
   QUI support of the uvdevice.

  * dropped the Kconfig dependency
  * reorganized the series:
    - Patch 1 now covers the introduction of the uvdevice and Attestation
    - Patch 2 adds QUI to uvdevice
    - Patch 3/4 add Kselftests for Attestation and QUI
  * fixed some nits
  * added some comments

v1->v2:
  * ioctl returns -ENOIOCTLCMD in case of a invalid ioctl command
  * streamlined reserved field test
  * default Kconfig is y instead of m
  * improved selftest documentation

Steffen Eiden (4):
  drivers/s390/char: Add Ultravisor io device
  drivers/s390/char: Add Query Ultravisor Information to uvdevice
  selftests: drivers/s390x: Add uvdevice tests
  selftests: drivers/s390x: Add uvdevice  QUI tests

 MAINTAINERS                                   |   3 +
 arch/s390/include/asm/uv.h                    |  23 +-
 arch/s390/include/uapi/asm/uvdevice.h         |  53 +++
 drivers/s390/char/Kconfig                     |  10 +
 drivers/s390/char/Makefile                    |   1 +
 drivers/s390/char/uvdevice.c                  | 320 ++++++++++++++++++
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/drivers/.gitignore    |   1 +
 .../selftests/drivers/s390x/uvdevice/Makefile |  22 ++
 .../selftests/drivers/s390x/uvdevice/config   |   1 +
 .../drivers/s390x/uvdevice/test_uvdevice.c    | 281 +++++++++++++++
 11 files changed, 715 insertions(+), 1 deletion(-)
 create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
 create mode 100644 drivers/s390/char/uvdevice.c
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/Makefile
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/config
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c

-- 
2.25.1

[PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Steffen Eiden]

This patch adds a new miscdevice to expose some Ultravisor functions
to userspace. Userspace can send IOCTLs to the uvdevice that will then
emit a corresponding Ultravisor Call and hands the result over to
userspace. The uvdevice is available if the Ultravisor Call facility is
present.
Userspace can call call the Retrieve Attestation Measurement
Ultravisor Call using IOCTLs on the uvdevice.

The uvdevice will do some sanity checks first.
Then, copy the request data to kernel space, build the UVCB,
perform the UV call, and copy the result back to userspace.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
---
 MAINTAINERS                           |   2 +
 arch/s390/include/asm/uv.h            |  23 ++-
 arch/s390/include/uapi/asm/uvdevice.h |  51 +++++
 drivers/s390/char/Kconfig             |  10 +
 drivers/s390/char/Makefile            |   1 +
 drivers/s390/char/uvdevice.c          | 264 ++++++++++++++++++++++++++
 6 files changed, 350 insertions(+), 1 deletion(-)
 create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
 create mode 100644 drivers/s390/char/uvdevice.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 777cd6fa2b3d..f32e876f45c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10577,9 +10577,11 @@ F:	Documentation/virt/kvm/s390*
 F:	arch/s390/include/asm/gmap.h
 F:	arch/s390/include/asm/kvm*
 F:	arch/s390/include/uapi/asm/kvm*
+F:	arch/s390/include/uapi/asm/uvdevice.h
 F:	arch/s390/kernel/uv.c
 F:	arch/s390/kvm/
 F:	arch/s390/mm/gmap.c
+F:	drivers/s390/char/uvdevice.c
 F:	tools/testing/selftests/kvm/*/s390x/
 F:	tools/testing/selftests/kvm/s390x/
 
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 86218382d29c..760dda4024b9 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -2,7 +2,7 @@
 /*
  * Ultravisor Interfaces
  *
- * Copyright IBM Corp. 2019
+ * Copyright IBM Corp. 2019, 2022
  *
  * Author(s):
  *	Vasily Gorbik <gor@linux.ibm.com>
@@ -52,6 +52,7 @@
 #define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
 #define UVC_CMD_SET_SHARED_ACCESS	0x1000
 #define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
+#define UVC_CMD_RETR_ATTEST		0x1020
 
 /* Bits in installed uv calls */
 enum uv_cmds_inst {
@@ -76,6 +77,7 @@ enum uv_cmds_inst {
 	BIT_UVC_CMD_UNSHARE_ALL = 20,
 	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
 	BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22,
+	BIT_UVC_CMD_RETR_ATTEST = 28,
 };
 
 enum uv_feat_ind {
@@ -218,6 +220,25 @@ struct uv_cb_share {
 	u64 reserved28;
 } __packed __aligned(8);
 
+/* Retrieve Attestation Measurement */
+struct uv_cb_attest {
+	struct uv_cb_header header;	/* 0x0000 */
+	u64 reserved08[2];		/* 0x0008 */
+	u64 arcb_addr;			/* 0x0018 */
+	u64 cont_token;			/* 0x0020 */
+	u8  reserved28[6];		/* 0x0028 */
+	u16 user_data_len;		/* 0x002e */
+	u8  user_data[256];		/* 0x0030 */
+	u32 reserved130[3];		/* 0x0130 */
+	u32 meas_len;			/* 0x013c */
+	u64 meas_addr;			/* 0x0140 */
+	u8  config_uid[16];		/* 0x0148 */
+	u32 reserved158;		/* 0x0158 */
+	u32 add_data_len;		/* 0x015c */
+	u64 add_data_addr;		/* 0x0160 */
+	u64 reserved168[4];		/* 0x0168 */
+} __packed __aligned(8);
+
 static inline int __uv_call(unsigned long r1, unsigned long r2)
 {
 	int cc;
diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
new file mode 100644
index 000000000000..d40f69345c75
--- /dev/null
+++ b/arch/s390/include/uapi/asm/uvdevice.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ *  Copyright IBM Corp. 2022
+ *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
+ */
+#ifndef __S390X_ASM_UVDEVICE_H
+#define __S390X_ASM_UVDEVICE_H
+
+#include <linux/types.h>
+
+struct uvio_ioctl_cb {
+	__u32 flags;
+	__u16 uv_rc;			/* UV header rc value */
+	__u16 uv_rrc;			/* UV header rrc value */
+	__u64 argument_addr;		/* Userspace address of uvio argument */
+	__u32 argument_len;
+	__u8  reserved14[0x40 - 0x14];	/* must be zero */
+};
+
+#define UVIO_ATT_USER_DATA_LEN		0x100
+#define UVIO_ATT_UID_LEN		0x10
+struct uvio_attest {
+	__u64 arcb_addr;				/* 0x0000 */
+	__u64 meas_addr;				/* 0x0008 */
+	__u64 add_data_addr;				/* 0x0010 */
+	__u8  user_data[UVIO_ATT_USER_DATA_LEN];	/* 0x0018 */
+	__u8  config_uid[UVIO_ATT_UID_LEN];		/* 0x0118 */
+	__u32 arcb_len;					/* 0x0128 */
+	__u32 meas_len;					/* 0x012c */
+	__u32 add_data_len;				/* 0x0130 */
+	__u16 user_data_len;				/* 0x0134 */
+	__u16 reserved136;				/* 0x0136 */
+};
+
+/*
+ * 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
+ * often way smaller. By allowing larger buffer sizes we hopefully do not need
+ * to update the code with every machine update. It is therefore possible for
+ * userspace to request more memory than actually used by kernel/UV.
+ */
+#define UVIO_ATT_ARCB_MAX_LEN		0x100000
+#define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
+#define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
+
+#define UVIO_DEVICE_NAME "uv"
+#define UVIO_TYPE_UVC 'u'
+
+#define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
+
+#endif  /* __S390X_ASM_UVDEVICE_H */
diff --git a/drivers/s390/char/Kconfig b/drivers/s390/char/Kconfig
index 6cc4b19acf85..c8fa466815ac 100644
--- a/drivers/s390/char/Kconfig
+++ b/drivers/s390/char/Kconfig
@@ -184,3 +184,13 @@ config S390_VMUR
 	depends on S390
 	help
 	  Character device driver for z/VM reader, puncher and printer.
+
+config S390_UV_UAPI
+	def_tristate y
+	prompt "Ultravisor userspace API"
+	help
+	  Selecting exposes parts of the UV interface to userspace
+	  by providing a misc character device at /dev/uv.
+	  Using IOCTLs one can interact with the UV.
+	  The device is only available if the Ultravisor
+	  Facility (158) is present.
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index c6fdb81a068a..ce32270082f5 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_MONREADER) += monreader.o
 obj-$(CONFIG_MONWRITER) += monwriter.o
 obj-$(CONFIG_S390_VMUR) += vmur.o
 obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
+obj-$(CONFIG_S390_UV_UAPI) += uvdevice.o
 
 hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
 obj-$(CONFIG_HMC_DRV) += hmcdrv.o
diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
new file mode 100644
index 000000000000..b720dc8d0bd9
--- /dev/null
+++ b/drivers/s390/char/uvdevice.c
@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright IBM Corp. 2022
+ *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
+ *
+ *  This file provides a Linux misc device to give userspace access to some
+ *  Ultravisor (UV) functions. The device only accepts IOCTLs and will only
+ *  be present if the Ultravisor facility (158) is present.
+ *
+ *  When userspace sends a valid IOCTL uvdevice will copy the input data to
+ *  kernel space, do some basic validity checks to avoid kernel/system
+ *  corruption. Any other check that the Ultravisor does will not be done by
+ *  the uvdevice to keep changes minimal when adding new functionalities
+ *  to existing UV-calls.
+ *  After the checks uvdevice builds a corresponding
+ *  Ultravisor Call Control Block, and sends the request to the Ultravisor.
+ *  Then, it copies the response, including the return codes, back to userspace.
+ *  It is the responsibility of the userspace to check for any error issued
+ *  by UV and to interpret the UV response. The uvdevice acts as a communication
+ *  channel for userspace to the Ultravisor.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include <asm/uvdevice.h>
+#include <asm/uv.h>
+
+static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
+				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
+{
+	void __user *user_buf_arcb = (void __user *)uvio_attest->arcb_addr;
+
+	if (copy_from_user(arcb, user_buf_arcb, uvio_attest->arcb_len))
+		return -EFAULT;
+
+	uvcb_attest->header.len = sizeof(*uvcb_attest);
+	uvcb_attest->header.cmd = UVC_CMD_RETR_ATTEST;
+	uvcb_attest->arcb_addr = (u64)arcb;
+	uvcb_attest->cont_token = 0;
+	uvcb_attest->user_data_len = uvio_attest->user_data_len;
+	memcpy(uvcb_attest->user_data, uvio_attest->user_data, sizeof(uvcb_attest->user_data));
+	uvcb_attest->meas_len = uvio_attest->meas_len;
+	uvcb_attest->meas_addr = (u64)meas;
+	uvcb_attest->add_data_len = uvio_attest->add_data_len;
+	uvcb_attest->add_data_addr = (u64)add_data;
+
+	return 0;
+}
+
+static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest,
+					   struct uvio_ioctl_cb *uv_ioctl,
+					   u8 *measurement, u8 *add_data,
+					   struct uvio_attest *uvio_attest)
+{
+	struct uvio_attest __user *user_uvio_attest = (void __user *)uv_ioctl->argument_addr;
+	void __user *user_buf_add = (void __user *)uvio_attest->add_data_addr;
+	void __user *user_buf_meas = (void __user *)uvio_attest->meas_addr;
+	void __user *user_buf_uid = &user_uvio_attest->config_uid;
+
+	if (copy_to_user(user_buf_meas, measurement, uvio_attest->meas_len))
+		return -EFAULT;
+	if (add_data && copy_to_user(user_buf_add, add_data, uvio_attest->add_data_len))
+		return -EFAULT;
+	if (copy_to_user(user_buf_uid, uvcb_attest->config_uid, sizeof(uvcb_attest->config_uid)))
+		return -EFAULT;
+	return 0;
+}
+
+static int get_uvio_attest(struct uvio_ioctl_cb *uv_ioctl, struct uvio_attest *uvio_attest)
+{
+	u8 __user *user_arg_buf = (u8 __user *)uv_ioctl->argument_addr;
+
+	if (copy_from_user(uvio_attest, user_arg_buf, sizeof(*uvio_attest)))
+		return -EFAULT;
+
+	if (uvio_attest->arcb_len > UVIO_ATT_ARCB_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->arcb_len == 0)
+		return -EINVAL;
+	if (uvio_attest->meas_len > UVIO_ATT_MEASUREMENT_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->meas_len == 0)
+		return -EINVAL;
+	if (uvio_attest->add_data_len > UVIO_ATT_ADDITIONAL_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->reserved136)
+		return -EINVAL;
+	return 0;
+}
+
+/**
+ * uvio_attestation() - Perform a Retrieve Attestation Measurement UVC.
+ *
+ * uv_ioctl: ioctl control block
+ *
+ * uvio_attestation() does a  Retrieve Attestation Measurement Ultravisor Call.
+ * It verifies that the given userspace addresses are valid and request sizes
+ * are sane. Every other check is made by the Ultravisor (UV) and won't result
+ * in a negative return value. It copies the input to kernelspace, builds the
+ * request, sends the UV-call, and copies the result to userspace.
+ *
+ * The Attestation Request has two input and two outputs.
+ * ARCB and User Data are inputs for the UV generated by userspace.
+ * Measurement and Additional Data are outputs for userspace generated by UV.
+ *
+ * The Attestation Request Control Block (ARCB) is a cryptographically verified
+ * and secured request to UV and User Data is some plaintext data which is
+ * going to be included in the Attestation Measurement calculation.
+ *
+ * Measurement is a cryptographic measurement of the callers properties,
+ * optional data configured by the ARCB and the user data. If specified by the
+ * ARCB, UV will add some Additional Data to the measurement calculation.
+ * This Additional Data is then returned as well.
+ *
+ * If the Retrieve Attestation Measurement 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_attestation(struct uvio_ioctl_cb *uv_ioctl)
+{
+	struct uv_cb_attest *uvcb_attest = NULL;
+	struct uvio_attest *uvio_attest = NULL;
+	u8 *measurement = NULL;
+	u8 *add_data = NULL;
+	u8 *arcb = NULL;
+	int ret;
+
+	ret = -EINVAL;
+	if (uv_ioctl->argument_len != sizeof(*uvio_attest))
+		goto out;
+
+	ret = -ENOMEM;
+	uvio_attest = kzalloc(sizeof(*uvio_attest), GFP_KERNEL);
+	if (!uvio_attest)
+		goto out;
+
+	ret = get_uvio_attest(uv_ioctl, uvio_attest);
+	if (ret)
+		goto out;
+
+	ret = -ENOMEM;
+	arcb = kvzalloc(uvio_attest->arcb_len, GFP_KERNEL);
+	measurement = kvzalloc(uvio_attest->meas_len, GFP_KERNEL);
+	if (!arcb || !measurement)
+		goto out;
+
+	if (uvio_attest->add_data_len) {
+		add_data = kvzalloc(uvio_attest->add_data_len, GFP_KERNEL);
+		if (!add_data)
+			goto out;
+	}
+
+	uvcb_attest = kzalloc(sizeof(*uvcb_attest), GFP_KERNEL);
+	if (!uvcb_attest)
+		goto out;
+
+	ret = uvio_build_uvcb_attest(uvcb_attest, arcb,  measurement, add_data, uvio_attest);
+	if (ret)
+		goto out;
+
+	uv_call_sched(0, (u64)uvcb_attest);
+
+	uv_ioctl->uv_rc = uvcb_attest->header.rc;
+	uv_ioctl->uv_rrc = uvcb_attest->header.rrc;
+
+	ret = uvio_copy_attest_result_to_user(uvcb_attest, uv_ioctl, measurement, add_data,
+					      uvio_attest);
+out:
+	kvfree(arcb);
+	kvfree(measurement);
+	kvfree(add_data);
+	kfree(uvio_attest);
+	kfree(uvcb_attest);
+	return ret;
+}
+
+static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp)
+{
+	if (copy_from_user(ioctl, argp, sizeof(*ioctl)))
+		return -EFAULT;
+	if (ioctl->flags != 0)
+		return -EINVAL;
+	if (memchr_inv(ioctl->reserved14, 0, sizeof(ioctl->reserved14)))
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * IOCTL entry point for the Ultravisor device.
+ */
+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;
+
+	ret = -ENOMEM;
+	uv_ioctl = vzalloc(sizeof(*uv_ioctl));
+	if (!uv_ioctl)
+		goto out;
+
+	switch (cmd) {
+	case UVIO_IOCTL_ATT:
+		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
+		if (ret)
+			goto out;
+		ret = uvio_attestation(uv_ioctl);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+	if (ret)
+		goto out;
+
+	if (copy_to_user(argp, uv_ioctl, sizeof(*uv_ioctl)))
+		ret = -EFAULT;
+
+ out:
+	vfree(uv_ioctl);
+	return ret;
+}
+
+static const struct file_operations uvio_dev_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = uvio_ioctl,
+	.llseek = no_llseek,
+};
+
+static struct miscdevice uvio_dev_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = UVIO_DEVICE_NAME,
+	.fops = &uvio_dev_fops,
+};
+
+static void __exit uvio_dev_exit(void)
+{
+	misc_deregister(&uvio_dev_miscdev);
+}
+
+static int __init uvio_dev_init(void)
+{
+	if (!test_facility(158))
+		return -ENXIO;
+	return misc_register(&uvio_dev_miscdev);
+}
+
+module_init(uvio_dev_init);
+module_exit(uvio_dev_exit);
+
+MODULE_AUTHOR("IBM Corporation");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Ultravisor UAPI driver");
-- 
2.25.1

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Janosch Frank]

On 3/4/22 15:11, Steffen Eiden wrote:
> This patch adds a new miscdevice to expose some Ultravisor functions
> to userspace. Userspace can send IOCTLs to the uvdevice that will then
> emit a corresponding Ultravisor Call and hands the result over to
> userspace. The uvdevice is available if the Ultravisor Call facility is
> present.
> Userspace can call call the Retrieve Attestation Measurement
> Ultravisor Call using IOCTLs on the uvdevice.
> 
> The uvdevice will do some sanity checks first.
> Then, copy the request data to kernel space, build the UVCB,
> perform the UV call, and copy the result back to userspace.

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>


> 
> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
> ---
>   MAINTAINERS                           |   2 +
>   arch/s390/include/asm/uv.h            |  23 ++-
>   arch/s390/include/uapi/asm/uvdevice.h |  51 +++++
>   drivers/s390/char/Kconfig             |  10 +
>   drivers/s390/char/Makefile            |   1 +
>   drivers/s390/char/uvdevice.c          | 264 ++++++++++++++++++++++++++
>   6 files changed, 350 insertions(+), 1 deletion(-)
>   create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
>   create mode 100644 drivers/s390/char/uvdevice.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 777cd6fa2b3d..f32e876f45c2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10577,9 +10577,11 @@ F:	Documentation/virt/kvm/s390*
>   F:	arch/s390/include/asm/gmap.h
>   F:	arch/s390/include/asm/kvm*
>   F:	arch/s390/include/uapi/asm/kvm*
> +F:	arch/s390/include/uapi/asm/uvdevice.h
>   F:	arch/s390/kernel/uv.c
>   F:	arch/s390/kvm/
>   F:	arch/s390/mm/gmap.c
> +F:	drivers/s390/char/uvdevice.c
>   F:	tools/testing/selftests/kvm/*/s390x/
>   F:	tools/testing/selftests/kvm/s390x/
>   
> diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
> index 86218382d29c..760dda4024b9 100644
> --- a/arch/s390/include/asm/uv.h
> +++ b/arch/s390/include/asm/uv.h
> @@ -2,7 +2,7 @@
>   /*
>    * Ultravisor Interfaces
>    *
> - * Copyright IBM Corp. 2019
> + * Copyright IBM Corp. 2019, 2022
>    *
>    * Author(s):
>    *	Vasily Gorbik <gor@linux.ibm.com>
> @@ -52,6 +52,7 @@
>   #define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
>   #define UVC_CMD_SET_SHARED_ACCESS	0x1000
>   #define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
> +#define UVC_CMD_RETR_ATTEST		0x1020
>   
>   /* Bits in installed uv calls */
>   enum uv_cmds_inst {
> @@ -76,6 +77,7 @@ enum uv_cmds_inst {
>   	BIT_UVC_CMD_UNSHARE_ALL = 20,
>   	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
>   	BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22,
> +	BIT_UVC_CMD_RETR_ATTEST = 28,
>   };
>   
>   enum uv_feat_ind {
> @@ -218,6 +220,25 @@ struct uv_cb_share {
>   	u64 reserved28;
>   } __packed __aligned(8);
>   
> +/* Retrieve Attestation Measurement */
> +struct uv_cb_attest {
> +	struct uv_cb_header header;	/* 0x0000 */
> +	u64 reserved08[2];		/* 0x0008 */
> +	u64 arcb_addr;			/* 0x0018 */
> +	u64 cont_token;			/* 0x0020 */
> +	u8  reserved28[6];		/* 0x0028 */
> +	u16 user_data_len;		/* 0x002e */
> +	u8  user_data[256];		/* 0x0030 */
> +	u32 reserved130[3];		/* 0x0130 */
> +	u32 meas_len;			/* 0x013c */
> +	u64 meas_addr;			/* 0x0140 */
> +	u8  config_uid[16];		/* 0x0148 */
> +	u32 reserved158;		/* 0x0158 */
> +	u32 add_data_len;		/* 0x015c */
> +	u64 add_data_addr;		/* 0x0160 */
> +	u64 reserved168[4];		/* 0x0168 */
> +} __packed __aligned(8);
> +
>   static inline int __uv_call(unsigned long r1, unsigned long r2)
>   {
>   	int cc;
> diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
> new file mode 100644
> index 000000000000..d40f69345c75
> --- /dev/null
> +++ b/arch/s390/include/uapi/asm/uvdevice.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + *  Copyright IBM Corp. 2022
> + *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
> + */
> +#ifndef __S390X_ASM_UVDEVICE_H
> +#define __S390X_ASM_UVDEVICE_H
> +
> +#include <linux/types.h>
> +
> +struct uvio_ioctl_cb {
> +	__u32 flags;
> +	__u16 uv_rc;			/* UV header rc value */
> +	__u16 uv_rrc;			/* UV header rrc value */
> +	__u64 argument_addr;		/* Userspace address of uvio argument */
> +	__u32 argument_len;
> +	__u8  reserved14[0x40 - 0x14];	/* must be zero */
> +};
> +
> +#define UVIO_ATT_USER_DATA_LEN		0x100
> +#define UVIO_ATT_UID_LEN		0x10
> +struct uvio_attest {
> +	__u64 arcb_addr;				/* 0x0000 */
> +	__u64 meas_addr;				/* 0x0008 */
> +	__u64 add_data_addr;				/* 0x0010 */
> +	__u8  user_data[UVIO_ATT_USER_DATA_LEN];	/* 0x0018 */
> +	__u8  config_uid[UVIO_ATT_UID_LEN];		/* 0x0118 */
> +	__u32 arcb_len;					/* 0x0128 */
> +	__u32 meas_len;					/* 0x012c */
> +	__u32 add_data_len;				/* 0x0130 */
> +	__u16 user_data_len;				/* 0x0134 */
> +	__u16 reserved136;				/* 0x0136 */
> +};
> +
> +/*
> + * 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
> + * often way smaller. By allowing larger buffer sizes we hopefully do not need
> + * to update the code with every machine update. It is therefore possible for
> + * userspace to request more memory than actually used by kernel/UV.
> + */
> +#define UVIO_ATT_ARCB_MAX_LEN		0x100000
> +#define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
> +#define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
> +
> +#define UVIO_DEVICE_NAME "uv"
> +#define UVIO_TYPE_UVC 'u'
> +
> +#define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
> +
> +#endif  /* __S390X_ASM_UVDEVICE_H */
> diff --git a/drivers/s390/char/Kconfig b/drivers/s390/char/Kconfig
> index 6cc4b19acf85..c8fa466815ac 100644
> --- a/drivers/s390/char/Kconfig
> +++ b/drivers/s390/char/Kconfig
> @@ -184,3 +184,13 @@ config S390_VMUR
>   	depends on S390
>   	help
>   	  Character device driver for z/VM reader, puncher and printer.
> +
> +config S390_UV_UAPI
> +	def_tristate y
> +	prompt "Ultravisor userspace API"
> +	help
> +	  Selecting exposes parts of the UV interface to userspace
> +	  by providing a misc character device at /dev/uv.
> +	  Using IOCTLs one can interact with the UV.
> +	  The device is only available if the Ultravisor
> +	  Facility (158) is present.
> diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
> index c6fdb81a068a..ce32270082f5 100644
> --- a/drivers/s390/char/Makefile
> +++ b/drivers/s390/char/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_MONREADER) += monreader.o
>   obj-$(CONFIG_MONWRITER) += monwriter.o
>   obj-$(CONFIG_S390_VMUR) += vmur.o
>   obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
> +obj-$(CONFIG_S390_UV_UAPI) += uvdevice.o
>   
>   hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
>   obj-$(CONFIG_HMC_DRV) += hmcdrv.o
> diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
> new file mode 100644
> index 000000000000..b720dc8d0bd9
> --- /dev/null
> +++ b/drivers/s390/char/uvdevice.c
> @@ -0,0 +1,264 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Copyright IBM Corp. 2022
> + *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
> + *
> + *  This file provides a Linux misc device to give userspace access to some
> + *  Ultravisor (UV) functions. The device only accepts IOCTLs and will only
> + *  be present if the Ultravisor facility (158) is present.
> + *
> + *  When userspace sends a valid IOCTL uvdevice will copy the input data to
> + *  kernel space, do some basic validity checks to avoid kernel/system
> + *  corruption. Any other check that the Ultravisor does will not be done by
> + *  the uvdevice to keep changes minimal when adding new functionalities
> + *  to existing UV-calls.
> + *  After the checks uvdevice builds a corresponding
> + *  Ultravisor Call Control Block, and sends the request to the Ultravisor.
> + *  Then, it copies the response, including the return codes, back to userspace.
> + *  It is the responsibility of the userspace to check for any error issued
> + *  by UV and to interpret the UV response. The uvdevice acts as a communication
> + *  channel for userspace to the Ultravisor.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/miscdevice.h>
> +#include <linux/types.h>
> +#include <linux/stddef.h>
> +#include <linux/vmalloc.h>
> +#include <linux/slab.h>
> +
> +#include <asm/uvdevice.h>
> +#include <asm/uv.h>
> +
> +static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
> +				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
> +{
> +	void __user *user_buf_arcb = (void __user *)uvio_attest->arcb_addr;
> +
> +	if (copy_from_user(arcb, user_buf_arcb, uvio_attest->arcb_len))
> +		return -EFAULT;
> +
> +	uvcb_attest->header.len = sizeof(*uvcb_attest);
> +	uvcb_attest->header.cmd = UVC_CMD_RETR_ATTEST;
> +	uvcb_attest->arcb_addr = (u64)arcb;
> +	uvcb_attest->cont_token = 0;
> +	uvcb_attest->user_data_len = uvio_attest->user_data_len;
> +	memcpy(uvcb_attest->user_data, uvio_attest->user_data, sizeof(uvcb_attest->user_data));
> +	uvcb_attest->meas_len = uvio_attest->meas_len;
> +	uvcb_attest->meas_addr = (u64)meas;
> +	uvcb_attest->add_data_len = uvio_attest->add_data_len;
> +	uvcb_attest->add_data_addr = (u64)add_data;
> +
> +	return 0;
> +}
> +
> +static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest,
> +					   struct uvio_ioctl_cb *uv_ioctl,
> +					   u8 *measurement, u8 *add_data,
> +					   struct uvio_attest *uvio_attest)
> +{
> +	struct uvio_attest __user *user_uvio_attest = (void __user *)uv_ioctl->argument_addr;
> +	void __user *user_buf_add = (void __user *)uvio_attest->add_data_addr;
> +	void __user *user_buf_meas = (void __user *)uvio_attest->meas_addr;
> +	void __user *user_buf_uid = &user_uvio_attest->config_uid;
> +
> +	if (copy_to_user(user_buf_meas, measurement, uvio_attest->meas_len))
> +		return -EFAULT;
> +	if (add_data && copy_to_user(user_buf_add, add_data, uvio_attest->add_data_len))
> +		return -EFAULT;
> +	if (copy_to_user(user_buf_uid, uvcb_attest->config_uid, sizeof(uvcb_attest->config_uid)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
> +static int get_uvio_attest(struct uvio_ioctl_cb *uv_ioctl, struct uvio_attest *uvio_attest)
> +{
> +	u8 __user *user_arg_buf = (u8 __user *)uv_ioctl->argument_addr;
> +
> +	if (copy_from_user(uvio_attest, user_arg_buf, sizeof(*uvio_attest)))
> +		return -EFAULT;
> +
> +	if (uvio_attest->arcb_len > UVIO_ATT_ARCB_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->arcb_len == 0)
> +		return -EINVAL;
> +	if (uvio_attest->meas_len > UVIO_ATT_MEASUREMENT_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->meas_len == 0)
> +		return -EINVAL;
> +	if (uvio_attest->add_data_len > UVIO_ATT_ADDITIONAL_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->reserved136)
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +/**
> + * uvio_attestation() - Perform a Retrieve Attestation Measurement UVC.
> + *
> + * uv_ioctl: ioctl control block
> + *
> + * uvio_attestation() does a  Retrieve Attestation Measurement Ultravisor Call.
> + * It verifies that the given userspace addresses are valid and request sizes
> + * are sane. Every other check is made by the Ultravisor (UV) and won't result
> + * in a negative return value. It copies the input to kernelspace, builds the
> + * request, sends the UV-call, and copies the result to userspace.
> + *
> + * The Attestation Request has two input and two outputs.
> + * ARCB and User Data are inputs for the UV generated by userspace.
> + * Measurement and Additional Data are outputs for userspace generated by UV.
> + *
> + * The Attestation Request Control Block (ARCB) is a cryptographically verified
> + * and secured request to UV and User Data is some plaintext data which is
> + * going to be included in the Attestation Measurement calculation.
> + *
> + * Measurement is a cryptographic measurement of the callers properties,
> + * optional data configured by the ARCB and the user data. If specified by the
> + * ARCB, UV will add some Additional Data to the measurement calculation.
> + * This Additional Data is then returned as well.
> + *
> + * If the Retrieve Attestation Measurement 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_attestation(struct uvio_ioctl_cb *uv_ioctl)
> +{
> +	struct uv_cb_attest *uvcb_attest = NULL;
> +	struct uvio_attest *uvio_attest = NULL;
> +	u8 *measurement = NULL;
> +	u8 *add_data = NULL;
> +	u8 *arcb = NULL;
> +	int ret;
> +
> +	ret = -EINVAL;
> +	if (uv_ioctl->argument_len != sizeof(*uvio_attest))
> +		goto out;
> +
> +	ret = -ENOMEM;
> +	uvio_attest = kzalloc(sizeof(*uvio_attest), GFP_KERNEL);
> +	if (!uvio_attest)
> +		goto out;
> +
> +	ret = get_uvio_attest(uv_ioctl, uvio_attest);
> +	if (ret)
> +		goto out;
> +
> +	ret = -ENOMEM;
> +	arcb = kvzalloc(uvio_attest->arcb_len, GFP_KERNEL);
> +	measurement = kvzalloc(uvio_attest->meas_len, GFP_KERNEL);
> +	if (!arcb || !measurement)
> +		goto out;
> +
> +	if (uvio_attest->add_data_len) {
> +		add_data = kvzalloc(uvio_attest->add_data_len, GFP_KERNEL);
> +		if (!add_data)
> +			goto out;
> +	}
> +
> +	uvcb_attest = kzalloc(sizeof(*uvcb_attest), GFP_KERNEL);
> +	if (!uvcb_attest)
> +		goto out;
> +
> +	ret = uvio_build_uvcb_attest(uvcb_attest, arcb,  measurement, add_data, uvio_attest);
> +	if (ret)
> +		goto out;
> +
> +	uv_call_sched(0, (u64)uvcb_attest);
> +
> +	uv_ioctl->uv_rc = uvcb_attest->header.rc;
> +	uv_ioctl->uv_rrc = uvcb_attest->header.rrc;
> +
> +	ret = uvio_copy_attest_result_to_user(uvcb_attest, uv_ioctl, measurement, add_data,
> +					      uvio_attest);
> +out:
> +	kvfree(arcb);
> +	kvfree(measurement);
> +	kvfree(add_data);
> +	kfree(uvio_attest);
> +	kfree(uvcb_attest);
> +	return ret;
> +}
> +
> +static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp)
> +{
> +	if (copy_from_user(ioctl, argp, sizeof(*ioctl)))
> +		return -EFAULT;
> +	if (ioctl->flags != 0)
> +		return -EINVAL;
> +	if (memchr_inv(ioctl->reserved14, 0, sizeof(ioctl->reserved14)))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +/*
> + * IOCTL entry point for the Ultravisor device.
> + */
> +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;
> +
> +	ret = -ENOMEM;
> +	uv_ioctl = vzalloc(sizeof(*uv_ioctl));
> +	if (!uv_ioctl)
> +		goto out;
> +
> +	switch (cmd) {
> +	case UVIO_IOCTL_ATT:
> +		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
> +		if (ret)
> +			goto out;
> +		ret = uvio_attestation(uv_ioctl);
> +		break;
> +	default:
> +		ret = -ENOIOCTLCMD;
> +		break;
> +	}
> +	if (ret)
> +		goto out;
> +
> +	if (copy_to_user(argp, uv_ioctl, sizeof(*uv_ioctl)))
> +		ret = -EFAULT;
> +
> + out:
> +	vfree(uv_ioctl);
> +	return ret;
> +}
> +
> +static const struct file_operations uvio_dev_fops = {
> +	.owner = THIS_MODULE,
> +	.unlocked_ioctl = uvio_ioctl,
> +	.llseek = no_llseek,
> +};
> +
> +static struct miscdevice uvio_dev_miscdev = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = UVIO_DEVICE_NAME,
> +	.fops = &uvio_dev_fops,
> +};
> +
> +static void __exit uvio_dev_exit(void)
> +{
> +	misc_deregister(&uvio_dev_miscdev);
> +}
> +
> +static int __init uvio_dev_init(void)
> +{
> +	if (!test_facility(158))
> +		return -ENXIO;
> +	return misc_register(&uvio_dev_miscdev);
> +}
> +
> +module_init(uvio_dev_init);
> +module_exit(uvio_dev_exit);
> +
> +MODULE_AUTHOR("IBM Corporation");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Ultravisor UAPI driver");

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Janosch Frank]

On 3/4/22 15:11, Steffen Eiden wrote:
> This patch adds a new miscdevice to expose some Ultravisor functions
> to userspace. Userspace can send IOCTLs to the uvdevice that will then
> emit a corresponding Ultravisor Call and hands the result over to
> userspace. The uvdevice is available if the Ultravisor Call facility is
> present.
> Userspace can call call the Retrieve Attestation Measurement

Checkpatch is unhappy about the repeating of "call".

> Ultravisor Call using IOCTLs on the uvdevice.
> 
> The uvdevice will do some sanity checks first.
> Then, copy the request data to kernel space, build the UVCB,
> perform the UV call, and copy the result back to userspace.
> 
> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
> ---
>   MAINTAINERS                           |   2 +
>   arch/s390/include/asm/uv.h            |  23 ++-
>   arch/s390/include/uapi/asm/uvdevice.h |  51 +++++
>   drivers/s390/char/Kconfig             |  10 +
>   drivers/s390/char/Makefile            |   1 +
>   drivers/s390/char/uvdevice.c          | 264 ++++++++++++++++++++++++++
>   6 files changed, 350 insertions(+), 1 deletion(-)
>   create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
>   create mode 100644 drivers/s390/char/uvdevice.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 777cd6fa2b3d..f32e876f45c2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -10577,9 +10577,11 @@ F:	Documentation/virt/kvm/s390*
>   F:	arch/s390/include/asm/gmap.h
>   F:	arch/s390/include/asm/kvm*
>   F:	arch/s390/include/uapi/asm/kvm*
> +F:	arch/s390/include/uapi/asm/uvdevice.h
>   F:	arch/s390/kernel/uv.c
>   F:	arch/s390/kvm/
>   F:	arch/s390/mm/gmap.c
> +F:	drivers/s390/char/uvdevice.c
>   F:	tools/testing/selftests/kvm/*/s390x/
>   F:	tools/testing/selftests/kvm/s390x/
>   
> diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
> index 86218382d29c..760dda4024b9 100644
> --- a/arch/s390/include/asm/uv.h
> +++ b/arch/s390/include/asm/uv.h
> @@ -2,7 +2,7 @@
>   /*
>    * Ultravisor Interfaces
>    *
> - * Copyright IBM Corp. 2019
> + * Copyright IBM Corp. 2019, 2022
>    *
>    * Author(s):
>    *	Vasily Gorbik <gor@linux.ibm.com>
> @@ -52,6 +52,7 @@
>   #define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
>   #define UVC_CMD_SET_SHARED_ACCESS	0x1000
>   #define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
> +#define UVC_CMD_RETR_ATTEST		0x1020
>   
>   /* Bits in installed uv calls */
>   enum uv_cmds_inst {
> @@ -76,6 +77,7 @@ enum uv_cmds_inst {
>   	BIT_UVC_CMD_UNSHARE_ALL = 20,
>   	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
>   	BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22,
> +	BIT_UVC_CMD_RETR_ATTEST = 28,
>   };
>   
>   enum uv_feat_ind {
> @@ -218,6 +220,25 @@ struct uv_cb_share {
>   	u64 reserved28;
>   } __packed __aligned(8);
>   
> +/* Retrieve Attestation Measurement */
> +struct uv_cb_attest {
> +	struct uv_cb_header header;	/* 0x0000 */
> +	u64 reserved08[2];		/* 0x0008 */
> +	u64 arcb_addr;			/* 0x0018 */
> +	u64 cont_token;			/* 0x0020 */
> +	u8  reserved28[6];		/* 0x0028 */
> +	u16 user_data_len;		/* 0x002e */
> +	u8  user_data[256];		/* 0x0030 */
> +	u32 reserved130[3];		/* 0x0130 */
> +	u32 meas_len;			/* 0x013c */
> +	u64 meas_addr;			/* 0x0140 */
> +	u8  config_uid[16];		/* 0x0148 */
> +	u32 reserved158;		/* 0x0158 */
> +	u32 add_data_len;		/* 0x015c */
> +	u64 add_data_addr;		/* 0x0160 */
> +	u64 reserved168[4];		/* 0x0168 */
> +} __packed __aligned(8);
> +
>   static inline int __uv_call(unsigned long r1, unsigned long r2)
>   {
>   	int cc;
> diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
> new file mode 100644
> index 000000000000..d40f69345c75
> --- /dev/null
> +++ b/arch/s390/include/uapi/asm/uvdevice.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + *  Copyright IBM Corp. 2022
> + *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
> + */
> +#ifndef __S390X_ASM_UVDEVICE_H
> +#define __S390X_ASM_UVDEVICE_H
> +
> +#include <linux/types.h>
> +
> +struct uvio_ioctl_cb {
> +	__u32 flags;
> +	__u16 uv_rc;			/* UV header rc value */
> +	__u16 uv_rrc;			/* UV header rrc value */
> +	__u64 argument_addr;		/* Userspace address of uvio argument */
> +	__u32 argument_len;
> +	__u8  reserved14[0x40 - 0x14];	/* must be zero */
> +};
> +
> +#define UVIO_ATT_USER_DATA_LEN		0x100
> +#define UVIO_ATT_UID_LEN		0x10
> +struct uvio_attest {
> +	__u64 arcb_addr;				/* 0x0000 */
> +	__u64 meas_addr;				/* 0x0008 */
> +	__u64 add_data_addr;				/* 0x0010 */
> +	__u8  user_data[UVIO_ATT_USER_DATA_LEN];	/* 0x0018 */
> +	__u8  config_uid[UVIO_ATT_UID_LEN];		/* 0x0118 */
> +	__u32 arcb_len;					/* 0x0128 */
> +	__u32 meas_len;					/* 0x012c */
> +	__u32 add_data_len;				/* 0x0130 */
> +	__u16 user_data_len;				/* 0x0134 */
> +	__u16 reserved136;				/* 0x0136 */
> +};
> +
> +/*
> + * 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
> + * often way smaller. By allowing larger buffer sizes we hopefully do not need
> + * to update the code with every machine update. It is therefore possible for
> + * userspace to request more memory than actually used by kernel/UV.
> + */
> +#define UVIO_ATT_ARCB_MAX_LEN		0x100000
> +#define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
> +#define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
> +
> +#define UVIO_DEVICE_NAME "uv"
> +#define UVIO_TYPE_UVC 'u'
> +
> +#define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
> +
> +#endif  /* __S390X_ASM_UVDEVICE_H */
> diff --git a/drivers/s390/char/Kconfig b/drivers/s390/char/Kconfig
> index 6cc4b19acf85..c8fa466815ac 100644
> --- a/drivers/s390/char/Kconfig
> +++ b/drivers/s390/char/Kconfig
> @@ -184,3 +184,13 @@ config S390_VMUR
>   	depends on S390
>   	help
>   	  Character device driver for z/VM reader, puncher and printer.
> +
> +config S390_UV_UAPI
> +	def_tristate y
> +	prompt "Ultravisor userspace API"
> +	help
> +	  Selecting exposes parts of the UV interface to userspace
> +	  by providing a misc character device at /dev/uv.
> +	  Using IOCTLs one can interact with the UV.
> +	  The device is only available if the Ultravisor
> +	  Facility (158) is present.
> diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
> index c6fdb81a068a..ce32270082f5 100644
> --- a/drivers/s390/char/Makefile
> +++ b/drivers/s390/char/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_MONREADER) += monreader.o
>   obj-$(CONFIG_MONWRITER) += monwriter.o
>   obj-$(CONFIG_S390_VMUR) += vmur.o
>   obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
> +obj-$(CONFIG_S390_UV_UAPI) += uvdevice.o
>   
>   hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
>   obj-$(CONFIG_HMC_DRV) += hmcdrv.o
> diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
> new file mode 100644
> index 000000000000..b720dc8d0bd9
> --- /dev/null
> +++ b/drivers/s390/char/uvdevice.c
> @@ -0,0 +1,264 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Copyright IBM Corp. 2022
> + *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
> + *
> + *  This file provides a Linux misc device to give userspace access to some
> + *  Ultravisor (UV) functions. The device only accepts IOCTLs and will only
> + *  be present if the Ultravisor facility (158) is present.
> + *
> + *  When userspace sends a valid IOCTL uvdevice will copy the input data to
> + *  kernel space, do some basic validity checks to avoid kernel/system
> + *  corruption. Any other check that the Ultravisor does will not be done by
> + *  the uvdevice to keep changes minimal when adding new functionalities
> + *  to existing UV-calls.
> + *  After the checks uvdevice builds a corresponding
> + *  Ultravisor Call Control Block, and sends the request to the Ultravisor.
> + *  Then, it copies the response, including the return codes, back to userspace.
> + *  It is the responsibility of the userspace to check for any error issued
> + *  by UV and to interpret the UV response. The uvdevice acts as a communication
> + *  channel for userspace to the Ultravisor.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/miscdevice.h>
> +#include <linux/types.h>
> +#include <linux/stddef.h>
> +#include <linux/vmalloc.h>
> +#include <linux/slab.h>
> +
> +#include <asm/uvdevice.h>
> +#include <asm/uv.h>
> +
> +static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
> +				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
> +{
> +	void __user *user_buf_arcb = (void __user *)uvio_attest->arcb_addr;
> +
> +	if (copy_from_user(arcb, user_buf_arcb, uvio_attest->arcb_len))
> +		return -EFAULT;
> +
> +	uvcb_attest->header.len = sizeof(*uvcb_attest);
> +	uvcb_attest->header.cmd = UVC_CMD_RETR_ATTEST;
> +	uvcb_attest->arcb_addr = (u64)arcb;
> +	uvcb_attest->cont_token = 0;
> +	uvcb_attest->user_data_len = uvio_attest->user_data_len;
> +	memcpy(uvcb_attest->user_data, uvio_attest->user_data, sizeof(uvcb_attest->user_data));
> +	uvcb_attest->meas_len = uvio_attest->meas_len;
> +	uvcb_attest->meas_addr = (u64)meas;
> +	uvcb_attest->add_data_len = uvio_attest->add_data_len;
> +	uvcb_attest->add_data_addr = (u64)add_data;
> +
> +	return 0;
> +}
> +
> +static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest,
> +					   struct uvio_ioctl_cb *uv_ioctl,
> +					   u8 *measurement, u8 *add_data,
> +					   struct uvio_attest *uvio_attest)
> +{
> +	struct uvio_attest __user *user_uvio_attest = (void __user *)uv_ioctl->argument_addr;
> +	void __user *user_buf_add = (void __user *)uvio_attest->add_data_addr;
> +	void __user *user_buf_meas = (void __user *)uvio_attest->meas_addr;
> +	void __user *user_buf_uid = &user_uvio_attest->config_uid;
> +
> +	if (copy_to_user(user_buf_meas, measurement, uvio_attest->meas_len))
> +		return -EFAULT;
> +	if (add_data && copy_to_user(user_buf_add, add_data, uvio_attest->add_data_len))
> +		return -EFAULT;
> +	if (copy_to_user(user_buf_uid, uvcb_attest->config_uid, sizeof(uvcb_attest->config_uid)))
> +		return -EFAULT;
> +	return 0;
> +}
> +
> +static int get_uvio_attest(struct uvio_ioctl_cb *uv_ioctl, struct uvio_attest *uvio_attest)
> +{
> +	u8 __user *user_arg_buf = (u8 __user *)uv_ioctl->argument_addr;
> +
> +	if (copy_from_user(uvio_attest, user_arg_buf, sizeof(*uvio_attest)))
> +		return -EFAULT;
> +
> +	if (uvio_attest->arcb_len > UVIO_ATT_ARCB_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->arcb_len == 0)
> +		return -EINVAL;
> +	if (uvio_attest->meas_len > UVIO_ATT_MEASUREMENT_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->meas_len == 0)
> +		return -EINVAL;
> +	if (uvio_attest->add_data_len > UVIO_ATT_ADDITIONAL_MAX_LEN)
> +		return -EINVAL;
> +	if (uvio_attest->reserved136)
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +/**
> + * uvio_attestation() - Perform a Retrieve Attestation Measurement UVC.
> + *
> + * uv_ioctl: ioctl control block
> + *
> + * uvio_attestation() does a  Retrieve Attestation Measurement Ultravisor Call.
> + * It verifies that the given userspace addresses are valid and request sizes
> + * are sane. Every other check is made by the Ultravisor (UV) and won't result
> + * in a negative return value. It copies the input to kernelspace, builds the
> + * request, sends the UV-call, and copies the result to userspace.
> + *
> + * The Attestation Request has two input and two outputs.
> + * ARCB and User Data are inputs for the UV generated by userspace.
> + * Measurement and Additional Data are outputs for userspace generated by UV.
> + *
> + * The Attestation Request Control Block (ARCB) is a cryptographically verified
> + * and secured request to UV and User Data is some plaintext data which is
> + * going to be included in the Attestation Measurement calculation.
> + *
> + * Measurement is a cryptographic measurement of the callers properties,
> + * optional data configured by the ARCB and the user data. If specified by the
> + * ARCB, UV will add some Additional Data to the measurement calculation.
> + * This Additional Data is then returned as well.
> + *
> + * If the Retrieve Attestation Measurement 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_attestation(struct uvio_ioctl_cb *uv_ioctl)
> +{
> +	struct uv_cb_attest *uvcb_attest = NULL;
> +	struct uvio_attest *uvio_attest = NULL;
> +	u8 *measurement = NULL;
> +	u8 *add_data = NULL;
> +	u8 *arcb = NULL;
> +	int ret;
> +
> +	ret = -EINVAL;
> +	if (uv_ioctl->argument_len != sizeof(*uvio_attest))
> +		goto out;
> +
> +	ret = -ENOMEM;
> +	uvio_attest = kzalloc(sizeof(*uvio_attest), GFP_KERNEL);
> +	if (!uvio_attest)
> +		goto out;
> +
> +	ret = get_uvio_attest(uv_ioctl, uvio_attest);
> +	if (ret)
> +		goto out;
> +
> +	ret = -ENOMEM;
> +	arcb = kvzalloc(uvio_attest->arcb_len, GFP_KERNEL);
> +	measurement = kvzalloc(uvio_attest->meas_len, GFP_KERNEL);
> +	if (!arcb || !measurement)
> +		goto out;
> +
> +	if (uvio_attest->add_data_len) {
> +		add_data = kvzalloc(uvio_attest->add_data_len, GFP_KERNEL);
> +		if (!add_data)
> +			goto out;
> +	}
> +
> +	uvcb_attest = kzalloc(sizeof(*uvcb_attest), GFP_KERNEL);
> +	if (!uvcb_attest)
> +		goto out;
> +
> +	ret = uvio_build_uvcb_attest(uvcb_attest, arcb,  measurement, add_data, uvio_attest);
> +	if (ret)
> +		goto out;
> +
> +	uv_call_sched(0, (u64)uvcb_attest);
> +
> +	uv_ioctl->uv_rc = uvcb_attest->header.rc;
> +	uv_ioctl->uv_rrc = uvcb_attest->header.rrc;
> +
> +	ret = uvio_copy_attest_result_to_user(uvcb_attest, uv_ioctl, measurement, add_data,
> +					      uvio_attest);
> +out:
> +	kvfree(arcb);
> +	kvfree(measurement);
> +	kvfree(add_data);
> +	kfree(uvio_attest);
> +	kfree(uvcb_attest);
> +	return ret;
> +}
> +
> +static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp)
> +{
> +	if (copy_from_user(ioctl, argp, sizeof(*ioctl)))
> +		return -EFAULT;
> +	if (ioctl->flags != 0)
> +		return -EINVAL;
> +	if (memchr_inv(ioctl->reserved14, 0, sizeof(ioctl->reserved14)))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +/*
> + * IOCTL entry point for the Ultravisor device.
> + */
> +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;
> +
> +	ret = -ENOMEM;
> +	uv_ioctl = vzalloc(sizeof(*uv_ioctl));
> +	if (!uv_ioctl)
> +		goto out;
> +
> +	switch (cmd) {
> +	case UVIO_IOCTL_ATT:
> +		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
> +		if (ret)
> +			goto out;
> +		ret = uvio_attestation(uv_ioctl);
> +		break;
> +	default:
> +		ret = -ENOIOCTLCMD;
> +		break;
> +	}
> +	if (ret)
> +		goto out;
> +
> +	if (copy_to_user(argp, uv_ioctl, sizeof(*uv_ioctl)))
> +		ret = -EFAULT;
> +
> + out:
> +	vfree(uv_ioctl);
> +	return ret;
> +}
> +
> +static const struct file_operations uvio_dev_fops = {
> +	.owner = THIS_MODULE,
> +	.unlocked_ioctl = uvio_ioctl,
> +	.llseek = no_llseek,
> +};
> +
> +static struct miscdevice uvio_dev_miscdev = {
> +	.minor = MISC_DYNAMIC_MINOR,
> +	.name = UVIO_DEVICE_NAME,
> +	.fops = &uvio_dev_fops,
> +};
> +
> +static void __exit uvio_dev_exit(void)
> +{
> +	misc_deregister(&uvio_dev_miscdev);
> +}
> +
> +static int __init uvio_dev_init(void)
> +{
> +	if (!test_facility(158))
> +		return -ENXIO;
> +	return misc_register(&uvio_dev_miscdev);
> +}
> +
> +module_init(uvio_dev_init);
> +module_exit(uvio_dev_exit);
> +
> +MODULE_AUTHOR("IBM Corporation");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Ultravisor UAPI driver");

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device'

[Steffen Eiden]

This patch adds a new miscdevice to expose some Ultravisor functions
to userspace. Userspace can send IOCTLs to the uvdevice that will then
emit a corresponding Ultravisor Call and hands the result over to
userspace. The uvdevice is available if the Ultravisor Call facility is
present.
Userspace can call the Retrieve Attestation Measurement
Ultravisor Call using IOCTLs on the uvdevice.

The uvdevice will do some sanity checks first.
Then, copy the request data to kernel space, build the UVCB,
perform the UV call, and copy the result back to userspace.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

---
The Kconfig entry was below the comment 'S/390 tape hardware support'.
This is confusing, as UV has nothing to do with tapes.
I moved the entry upwards just before the 'S390_TAPE' config entry. 

 MAINTAINERS                           |   2 +
 arch/s390/include/asm/uv.h            |  23 ++-
 arch/s390/include/uapi/asm/uvdevice.h |  51 +++++
 drivers/s390/char/Kconfig             |  10 +
 drivers/s390/char/Makefile            |   1 +
 drivers/s390/char/uvdevice.c          | 264 ++++++++++++++++++++++++++
 6 files changed, 350 insertions(+), 1 deletion(-)
 create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
 create mode 100644 drivers/s390/char/uvdevice.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 777cd6fa2b3d..f32e876f45c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10577,9 +10577,11 @@ F:	Documentation/virt/kvm/s390*
 F:	arch/s390/include/asm/gmap.h
 F:	arch/s390/include/asm/kvm*
 F:	arch/s390/include/uapi/asm/kvm*
+F:	arch/s390/include/uapi/asm/uvdevice.h
 F:	arch/s390/kernel/uv.c
 F:	arch/s390/kvm/
 F:	arch/s390/mm/gmap.c
+F:	drivers/s390/char/uvdevice.c
 F:	tools/testing/selftests/kvm/*/s390x/
 F:	tools/testing/selftests/kvm/s390x/
 
diff --git a/arch/s390/include/asm/uv.h b/arch/s390/include/asm/uv.h
index 86218382d29c..760dda4024b9 100644
--- a/arch/s390/include/asm/uv.h
+++ b/arch/s390/include/asm/uv.h
@@ -2,7 +2,7 @@
 /*
  * Ultravisor Interfaces
  *
- * Copyright IBM Corp. 2019
+ * Copyright IBM Corp. 2019, 2022
  *
  * Author(s):
  *	Vasily Gorbik <gor@linux.ibm.com>
@@ -52,6 +52,7 @@
 #define UVC_CMD_UNPIN_PAGE_SHARED	0x0342
 #define UVC_CMD_SET_SHARED_ACCESS	0x1000
 #define UVC_CMD_REMOVE_SHARED_ACCESS	0x1001
+#define UVC_CMD_RETR_ATTEST		0x1020
 
 /* Bits in installed uv calls */
 enum uv_cmds_inst {
@@ -76,6 +77,7 @@ enum uv_cmds_inst {
 	BIT_UVC_CMD_UNSHARE_ALL = 20,
 	BIT_UVC_CMD_PIN_PAGE_SHARED = 21,
 	BIT_UVC_CMD_UNPIN_PAGE_SHARED = 22,
+	BIT_UVC_CMD_RETR_ATTEST = 28,
 };
 
 enum uv_feat_ind {
@@ -218,6 +220,25 @@ struct uv_cb_share {
 	u64 reserved28;
 } __packed __aligned(8);
 
+/* Retrieve Attestation Measurement */
+struct uv_cb_attest {
+	struct uv_cb_header header;	/* 0x0000 */
+	u64 reserved08[2];		/* 0x0008 */
+	u64 arcb_addr;			/* 0x0018 */
+	u64 cont_token;			/* 0x0020 */
+	u8  reserved28[6];		/* 0x0028 */
+	u16 user_data_len;		/* 0x002e */
+	u8  user_data[256];		/* 0x0030 */
+	u32 reserved130[3];		/* 0x0130 */
+	u32 meas_len;			/* 0x013c */
+	u64 meas_addr;			/* 0x0140 */
+	u8  config_uid[16];		/* 0x0148 */
+	u32 reserved158;		/* 0x0158 */
+	u32 add_data_len;		/* 0x015c */
+	u64 add_data_addr;		/* 0x0160 */
+	u64 reserved168[4];		/* 0x0168 */
+} __packed __aligned(8);
+
 static inline int __uv_call(unsigned long r1, unsigned long r2)
 {
 	int cc;
diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
new file mode 100644
index 000000000000..d40f69345c75
--- /dev/null
+++ b/arch/s390/include/uapi/asm/uvdevice.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ *  Copyright IBM Corp. 2022
+ *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
+ */
+#ifndef __S390X_ASM_UVDEVICE_H
+#define __S390X_ASM_UVDEVICE_H
+
+#include <linux/types.h>
+
+struct uvio_ioctl_cb {
+	__u32 flags;
+	__u16 uv_rc;			/* UV header rc value */
+	__u16 uv_rrc;			/* UV header rrc value */
+	__u64 argument_addr;		/* Userspace address of uvio argument */
+	__u32 argument_len;
+	__u8  reserved14[0x40 - 0x14];	/* must be zero */
+};
+
+#define UVIO_ATT_USER_DATA_LEN		0x100
+#define UVIO_ATT_UID_LEN		0x10
+struct uvio_attest {
+	__u64 arcb_addr;				/* 0x0000 */
+	__u64 meas_addr;				/* 0x0008 */
+	__u64 add_data_addr;				/* 0x0010 */
+	__u8  user_data[UVIO_ATT_USER_DATA_LEN];	/* 0x0018 */
+	__u8  config_uid[UVIO_ATT_UID_LEN];		/* 0x0118 */
+	__u32 arcb_len;					/* 0x0128 */
+	__u32 meas_len;					/* 0x012c */
+	__u32 add_data_len;				/* 0x0130 */
+	__u16 user_data_len;				/* 0x0134 */
+	__u16 reserved136;				/* 0x0136 */
+};
+
+/*
+ * 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
+ * often way smaller. By allowing larger buffer sizes we hopefully do not need
+ * to update the code with every machine update. It is therefore possible for
+ * userspace to request more memory than actually used by kernel/UV.
+ */
+#define UVIO_ATT_ARCB_MAX_LEN		0x100000
+#define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
+#define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
+
+#define UVIO_DEVICE_NAME "uv"
+#define UVIO_TYPE_UVC 'u'
+
+#define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
+
+#endif  /* __S390X_ASM_UVDEVICE_H */
diff --git a/drivers/s390/char/Kconfig b/drivers/s390/char/Kconfig
index 6cc4b19acf85..e9b9902abbaf 100644
--- a/drivers/s390/char/Kconfig
+++ b/drivers/s390/char/Kconfig
@@ -100,6 +100,16 @@ config SCLP_OFB
 	  This option enables the Open-for-Business interface to the s390
 	  Service Element.
 
+config S390_UV_UAPI
+	def_tristate y
+	prompt "Ultravisor userspace API"
+	help
+	  Selecting exposes parts of the UV interface to userspace
+	  by providing a misc character device at /dev/uv.
+	  Using IOCTLs one can interact with the UV.
+	  The device is only available if the Ultravisor
+	  Facility (158) is present.
+
 config S390_TAPE
 	def_tristate m
 	prompt "S/390 tape device support"
diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
index c6fdb81a068a..ce32270082f5 100644
--- a/drivers/s390/char/Makefile
+++ b/drivers/s390/char/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_MONREADER) += monreader.o
 obj-$(CONFIG_MONWRITER) += monwriter.o
 obj-$(CONFIG_S390_VMUR) += vmur.o
 obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
+obj-$(CONFIG_S390_UV_UAPI) += uvdevice.o
 
 hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
 obj-$(CONFIG_HMC_DRV) += hmcdrv.o
diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
new file mode 100644
index 000000000000..b720dc8d0bd9
--- /dev/null
+++ b/drivers/s390/char/uvdevice.c
@@ -0,0 +1,264 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Copyright IBM Corp. 2022
+ *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
+ *
+ *  This file provides a Linux misc device to give userspace access to some
+ *  Ultravisor (UV) functions. The device only accepts IOCTLs and will only
+ *  be present if the Ultravisor facility (158) is present.
+ *
+ *  When userspace sends a valid IOCTL uvdevice will copy the input data to
+ *  kernel space, do some basic validity checks to avoid kernel/system
+ *  corruption. Any other check that the Ultravisor does will not be done by
+ *  the uvdevice to keep changes minimal when adding new functionalities
+ *  to existing UV-calls.
+ *  After the checks uvdevice builds a corresponding
+ *  Ultravisor Call Control Block, and sends the request to the Ultravisor.
+ *  Then, it copies the response, including the return codes, back to userspace.
+ *  It is the responsibility of the userspace to check for any error issued
+ *  by UV and to interpret the UV response. The uvdevice acts as a communication
+ *  channel for userspace to the Ultravisor.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include <asm/uvdevice.h>
+#include <asm/uv.h>
+
+static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
+				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
+{
+	void __user *user_buf_arcb = (void __user *)uvio_attest->arcb_addr;
+
+	if (copy_from_user(arcb, user_buf_arcb, uvio_attest->arcb_len))
+		return -EFAULT;
+
+	uvcb_attest->header.len = sizeof(*uvcb_attest);
+	uvcb_attest->header.cmd = UVC_CMD_RETR_ATTEST;
+	uvcb_attest->arcb_addr = (u64)arcb;
+	uvcb_attest->cont_token = 0;
+	uvcb_attest->user_data_len = uvio_attest->user_data_len;
+	memcpy(uvcb_attest->user_data, uvio_attest->user_data, sizeof(uvcb_attest->user_data));
+	uvcb_attest->meas_len = uvio_attest->meas_len;
+	uvcb_attest->meas_addr = (u64)meas;
+	uvcb_attest->add_data_len = uvio_attest->add_data_len;
+	uvcb_attest->add_data_addr = (u64)add_data;
+
+	return 0;
+}
+
+static int uvio_copy_attest_result_to_user(struct uv_cb_attest *uvcb_attest,
+					   struct uvio_ioctl_cb *uv_ioctl,
+					   u8 *measurement, u8 *add_data,
+					   struct uvio_attest *uvio_attest)
+{
+	struct uvio_attest __user *user_uvio_attest = (void __user *)uv_ioctl->argument_addr;
+	void __user *user_buf_add = (void __user *)uvio_attest->add_data_addr;
+	void __user *user_buf_meas = (void __user *)uvio_attest->meas_addr;
+	void __user *user_buf_uid = &user_uvio_attest->config_uid;
+
+	if (copy_to_user(user_buf_meas, measurement, uvio_attest->meas_len))
+		return -EFAULT;
+	if (add_data && copy_to_user(user_buf_add, add_data, uvio_attest->add_data_len))
+		return -EFAULT;
+	if (copy_to_user(user_buf_uid, uvcb_attest->config_uid, sizeof(uvcb_attest->config_uid)))
+		return -EFAULT;
+	return 0;
+}
+
+static int get_uvio_attest(struct uvio_ioctl_cb *uv_ioctl, struct uvio_attest *uvio_attest)
+{
+	u8 __user *user_arg_buf = (u8 __user *)uv_ioctl->argument_addr;
+
+	if (copy_from_user(uvio_attest, user_arg_buf, sizeof(*uvio_attest)))
+		return -EFAULT;
+
+	if (uvio_attest->arcb_len > UVIO_ATT_ARCB_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->arcb_len == 0)
+		return -EINVAL;
+	if (uvio_attest->meas_len > UVIO_ATT_MEASUREMENT_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->meas_len == 0)
+		return -EINVAL;
+	if (uvio_attest->add_data_len > UVIO_ATT_ADDITIONAL_MAX_LEN)
+		return -EINVAL;
+	if (uvio_attest->reserved136)
+		return -EINVAL;
+	return 0;
+}
+
+/**
+ * uvio_attestation() - Perform a Retrieve Attestation Measurement UVC.
+ *
+ * uv_ioctl: ioctl control block
+ *
+ * uvio_attestation() does a  Retrieve Attestation Measurement Ultravisor Call.
+ * It verifies that the given userspace addresses are valid and request sizes
+ * are sane. Every other check is made by the Ultravisor (UV) and won't result
+ * in a negative return value. It copies the input to kernelspace, builds the
+ * request, sends the UV-call, and copies the result to userspace.
+ *
+ * The Attestation Request has two input and two outputs.
+ * ARCB and User Data are inputs for the UV generated by userspace.
+ * Measurement and Additional Data are outputs for userspace generated by UV.
+ *
+ * The Attestation Request Control Block (ARCB) is a cryptographically verified
+ * and secured request to UV and User Data is some plaintext data which is
+ * going to be included in the Attestation Measurement calculation.
+ *
+ * Measurement is a cryptographic measurement of the callers properties,
+ * optional data configured by the ARCB and the user data. If specified by the
+ * ARCB, UV will add some Additional Data to the measurement calculation.
+ * This Additional Data is then returned as well.
+ *
+ * If the Retrieve Attestation Measurement 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_attestation(struct uvio_ioctl_cb *uv_ioctl)
+{
+	struct uv_cb_attest *uvcb_attest = NULL;
+	struct uvio_attest *uvio_attest = NULL;
+	u8 *measurement = NULL;
+	u8 *add_data = NULL;
+	u8 *arcb = NULL;
+	int ret;
+
+	ret = -EINVAL;
+	if (uv_ioctl->argument_len != sizeof(*uvio_attest))
+		goto out;
+
+	ret = -ENOMEM;
+	uvio_attest = kzalloc(sizeof(*uvio_attest), GFP_KERNEL);
+	if (!uvio_attest)
+		goto out;
+
+	ret = get_uvio_attest(uv_ioctl, uvio_attest);
+	if (ret)
+		goto out;
+
+	ret = -ENOMEM;
+	arcb = kvzalloc(uvio_attest->arcb_len, GFP_KERNEL);
+	measurement = kvzalloc(uvio_attest->meas_len, GFP_KERNEL);
+	if (!arcb || !measurement)
+		goto out;
+
+	if (uvio_attest->add_data_len) {
+		add_data = kvzalloc(uvio_attest->add_data_len, GFP_KERNEL);
+		if (!add_data)
+			goto out;
+	}
+
+	uvcb_attest = kzalloc(sizeof(*uvcb_attest), GFP_KERNEL);
+	if (!uvcb_attest)
+		goto out;
+
+	ret = uvio_build_uvcb_attest(uvcb_attest, arcb,  measurement, add_data, uvio_attest);
+	if (ret)
+		goto out;
+
+	uv_call_sched(0, (u64)uvcb_attest);
+
+	uv_ioctl->uv_rc = uvcb_attest->header.rc;
+	uv_ioctl->uv_rrc = uvcb_attest->header.rrc;
+
+	ret = uvio_copy_attest_result_to_user(uvcb_attest, uv_ioctl, measurement, add_data,
+					      uvio_attest);
+out:
+	kvfree(arcb);
+	kvfree(measurement);
+	kvfree(add_data);
+	kfree(uvio_attest);
+	kfree(uvcb_attest);
+	return ret;
+}
+
+static int uvio_copy_and_check_ioctl(struct uvio_ioctl_cb *ioctl, void __user *argp)
+{
+	if (copy_from_user(ioctl, argp, sizeof(*ioctl)))
+		return -EFAULT;
+	if (ioctl->flags != 0)
+		return -EINVAL;
+	if (memchr_inv(ioctl->reserved14, 0, sizeof(ioctl->reserved14)))
+		return -EINVAL;
+
+	return 0;
+}
+
+/*
+ * IOCTL entry point for the Ultravisor device.
+ */
+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;
+
+	ret = -ENOMEM;
+	uv_ioctl = vzalloc(sizeof(*uv_ioctl));
+	if (!uv_ioctl)
+		goto out;
+
+	switch (cmd) {
+	case UVIO_IOCTL_ATT:
+		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
+		if (ret)
+			goto out;
+		ret = uvio_attestation(uv_ioctl);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+		break;
+	}
+	if (ret)
+		goto out;
+
+	if (copy_to_user(argp, uv_ioctl, sizeof(*uv_ioctl)))
+		ret = -EFAULT;
+
+ out:
+	vfree(uv_ioctl);
+	return ret;
+}
+
+static const struct file_operations uvio_dev_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = uvio_ioctl,
+	.llseek = no_llseek,
+};
+
+static struct miscdevice uvio_dev_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = UVIO_DEVICE_NAME,
+	.fops = &uvio_dev_fops,
+};
+
+static void __exit uvio_dev_exit(void)
+{
+	misc_deregister(&uvio_dev_miscdev);
+}
+
+static int __init uvio_dev_init(void)
+{
+	if (!test_facility(158))
+		return -ENXIO;
+	return misc_register(&uvio_dev_miscdev);
+}
+
+module_init(uvio_dev_init);
+module_exit(uvio_dev_exit);
+
+MODULE_AUTHOR("IBM Corporation");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Ultravisor UAPI driver");
-- 
2.30.2

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device'

[Greg KH]

On Thu, Mar 17, 2022 at 09:47:06AM +0000, Steffen Eiden wrote:
> This patch adds a new miscdevice to expose some Ultravisor functions
> to userspace. Userspace can send IOCTLs to the uvdevice that will then
> emit a corresponding Ultravisor Call and hands the result over to
> userspace. The uvdevice is available if the Ultravisor Call facility is
> present.
> Userspace can call the Retrieve Attestation Measurement
> Ultravisor Call using IOCTLs on the uvdevice.
> 
> The uvdevice will do some sanity checks first.
> Then, copy the request data to kernel space, build the UVCB,
> perform the UV call, and copy the result back to userspace.
> 
> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

Do you have a pointer to the userspace code that interacts with this
kernel driver?  That would be good to have to verify that the api here
is sane.

thanks,

greg k-h

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Steffen Eiden]

Hi greg,

On 3/17/22 10:59, Greg KH wrote:
> On Thu, Mar 17, 2022 at 09:47:06AM +0000, Steffen Eiden wrote:
>> This patch adds a new miscdevice to expose some Ultravisor functions
>> to userspace. Userspace can send IOCTLs to the uvdevice that will then
>> emit a corresponding Ultravisor Call and hands the result over to
>> userspace. The uvdevice is available if the Ultravisor Call facility is
>> present.
>> Userspace can call the Retrieve Attestation Measurement
>> Ultravisor Call using IOCTLs on the uvdevice.
>>
>> The uvdevice will do some sanity checks first.
>> Then, copy the request data to kernel space, build the UVCB,
>> perform the UV call, and copy the result back to userspace.
>>
>> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
>> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> 
> Do you have a pointer to the userspace code that interacts with this
> kernel driver?  That would be good to have to verify that the api here
> is sane.
> 
There is a userspace tool currently under development, however, not yet 
ready to be published.
Currently, I can only point to the Kselftest in this series and the 
kvm-unit-tests at 
https://lore.kernel.org/linux-s390/20220203091935.2716-1-seiden@linux.ibm.com/


> thanks,
> 
> greg k-h
> 

steffen

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Steffen Eiden]

Hi greg,

On 3/17/22 12:07, Steffen Eiden wrote:
> Hi greg,
> 
> On 3/17/22 10:59, Greg KH wrote:
>> On Thu, Mar 17, 2022 at 09:47:06AM +0000, Steffen Eiden wrote:
>>> This patch adds a new miscdevice to expose some Ultravisor functions
>>> to userspace. Userspace can send IOCTLs to the uvdevice that will then
>>> emit a corresponding Ultravisor Call and hands the result over to
>>> userspace. The uvdevice is available if the Ultravisor Call facility is
>>> present.
>>> Userspace can call the Retrieve Attestation Measurement
>>> Ultravisor Call using IOCTLs on the uvdevice.
>>>
>>> The uvdevice will do some sanity checks first.
>>> Then, copy the request data to kernel space, build the UVCB,
>>> perform the UV call, and copy the result back to userspace.
>>>
>>> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
>>> Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
>>
>> Do you have a pointer to the userspace code that interacts with this
>> kernel driver?  That would be good to have to verify that the api here
>> is sane.
>>
> There is a userspace tool currently under development, however, not yet 
> ready to be published.
> Currently, I can only point to the Kselftest in this series and the 
> kvm-unit-tests at 
> https://lore.kernel.org/linux-s390/20220203091935.2716-1-seiden@linux.ibm.com/ 
> 
I forgot to point out that the Attestation userspace tool will be 
open-source and included in the s390-tool package.
I can send you the current state of that tool in private if you want.

> 
> 
>> thanks,
>>
>> greg k-h
>>
> 
> steffen

steffen

Re: [PATCH v3 1/4] drivers/s390/char: Add Ultravisor io device

[Greg KH]

On Thu, Mar 17, 2022 at 12:07:58PM +0100, Steffen Eiden wrote:
> Hi greg,
> 
> On 3/17/22 10:59, Greg KH wrote:
> > On Thu, Mar 17, 2022 at 09:47:06AM +0000, Steffen Eiden wrote:
> > > This patch adds a new miscdevice to expose some Ultravisor functions
> > > to userspace. Userspace can send IOCTLs to the uvdevice that will then
> > > emit a corresponding Ultravisor Call and hands the result over to
> > > userspace. The uvdevice is available if the Ultravisor Call facility is
> > > present.
> > > Userspace can call the Retrieve Attestation Measurement
> > > Ultravisor Call using IOCTLs on the uvdevice.
> > > 
> > > The uvdevice will do some sanity checks first.
> > > Then, copy the request data to kernel space, build the UVCB,
> > > perform the UV call, and copy the result back to userspace.
> > > 
> > > Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
> > > Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
> > 
> > Do you have a pointer to the userspace code that interacts with this
> > kernel driver?  That would be good to have to verify that the api here
> > is sane.
> > 
> There is a userspace tool currently under development, however, not yet
> ready to be published.

Then really, this driver should not be merged until the user/kernel api
is determined to work properly, right?  Why submit this now if userspace
isn't working?

thanks,

greg k-h

[PATCH v3 2/4] drivers/s390/char: Add Query Ultravisor Information to uvdevice

[Steffen Eiden]

This patch enables userspace to call the Query Ultravisor Information
Ultravisor Call using IOCTLs on the uvdevice.

The uvdevice will do some sanity checks first, build the UVCB,
perform the UV call, and copy the result to userspace.

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
---
 arch/s390/include/uapi/asm/uvdevice.h |  2 +
 drivers/s390/char/uvdevice.c          | 56 +++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)

diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
index d40f69345c75..7520bdde3102 100644
--- a/arch/s390/include/uapi/asm/uvdevice.h
+++ b/arch/s390/include/uapi/asm/uvdevice.h
@@ -42,10 +42,12 @@ struct uvio_attest {
 #define UVIO_ATT_ARCB_MAX_LEN		0x100000
 #define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
 #define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
+#define UVIO_QUI_MAX_LEN		0x8000
 
 #define UVIO_DEVICE_NAME "uv"
 #define UVIO_TYPE_UVC 'u'
 
 #define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
+#define UVIO_IOCTL_QUI _IOWR(UVIO_TYPE_UVC, 0x02, struct uvio_ioctl_cb)
 
 #endif  /* __S390X_ASM_UVDEVICE_H */
diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
index b720dc8d0bd9..cfce8c5999e6 100644
--- a/drivers/s390/char/uvdevice.c
+++ b/drivers/s390/char/uvdevice.c
@@ -31,6 +31,55 @@
 #include <asm/uvdevice.h>
 #include <asm/uv.h>
 
+/**
+ * uvio_qui() - Perform a Query Ultravisor Information UVC.
+ *
+ * uv_ioctl: ioctl control block
+ *
+ * uvio_qui() does a Query Ultravisor Information (QUI) Ultravisor Call.
+ * It creates the uvc qui request and sends it to the Ultravisor. After that
+ * it copies the response to userspace and fills the rc and rrc of uv_ioctl
+ * uv_call with the response values of the Ultravisor.
+ *
+ * Create the UVC structure, send the UVC to UV and write the response in the ioctl struct.
+ *
+ * Return: 0 on success or a negative error code on error.
+ */
+static int uvio_qui(struct uvio_ioctl_cb *uv_ioctl)
+{
+	u8 __user *user_buf_addr = (__user u8 *)uv_ioctl->argument_addr;
+	size_t user_buf_len = uv_ioctl->argument_len;
+	struct uv_cb_header *uvcb_qui = NULL;
+	int ret;
+
+	/*
+	 * Do not check for a too small buffer. If userspace provides a buffer
+	 * that is too small the Ultravisor will complain.
+	 */
+	ret = -EINVAL;
+	if (!user_buf_len || user_buf_len > UVIO_QUI_MAX_LEN)
+		goto out;
+	ret = -ENOMEM;
+	uvcb_qui = kvzalloc(user_buf_len, GFP_KERNEL);
+	if (!uvcb_qui)
+		goto out;
+	uvcb_qui->len = user_buf_len;
+	uvcb_qui->cmd = UVC_CMD_QUI;
+
+	uv_call(0, (u64)uvcb_qui);
+
+	ret = -EFAULT;
+	if (copy_to_user(user_buf_addr, uvcb_qui, uvcb_qui->len))
+		goto out;
+	uv_ioctl->uv_rc = uvcb_qui->rc;
+	uv_ioctl->uv_rrc = uvcb_qui->rrc;
+
+	ret = 0;
+out:
+	kvfree(uvcb_qui);
+	return ret;
+}
+
 static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
 				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
 {
@@ -217,6 +266,13 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 			goto out;
 		ret = uvio_attestation(uv_ioctl);
 		break;
+	case UVIO_IOCTL_QUI:
+		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
+		if (ret)
+			goto out;
+		ret = uvio_qui(uv_ioctl);
+		break;
+
 	default:
 		ret = -ENOIOCTLCMD;
 		break;
-- 
2.25.1

Re: [PATCH v3 2/4] drivers/s390/char: Add Query Ultravisor Information to uvdevice

[Janosch Frank]

On 3/4/22 15:11, Steffen Eiden wrote:
> This patch enables userspace to call the Query Ultravisor Information
> Ultravisor Call using IOCTLs on the uvdevice.
> 
> The uvdevice will do some sanity checks first, build the UVCB,
> perform the UV call, and copy the result to userspace.
> 
> Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>


Reviewed-by: Janosch Frank <frankja@linux.ibm.com>

> ---
>   arch/s390/include/uapi/asm/uvdevice.h |  2 +
>   drivers/s390/char/uvdevice.c          | 56 +++++++++++++++++++++++++++
>   2 files changed, 58 insertions(+)
> 
> diff --git a/arch/s390/include/uapi/asm/uvdevice.h b/arch/s390/include/uapi/asm/uvdevice.h
> index d40f69345c75..7520bdde3102 100644
> --- a/arch/s390/include/uapi/asm/uvdevice.h
> +++ b/arch/s390/include/uapi/asm/uvdevice.h
> @@ -42,10 +42,12 @@ struct uvio_attest {
>   #define UVIO_ATT_ARCB_MAX_LEN		0x100000
>   #define UVIO_ATT_MEASUREMENT_MAX_LEN	0x8000
>   #define UVIO_ATT_ADDITIONAL_MAX_LEN	0x8000
> +#define UVIO_QUI_MAX_LEN		0x8000
>   
>   #define UVIO_DEVICE_NAME "uv"
>   #define UVIO_TYPE_UVC 'u'
>   
>   #define UVIO_IOCTL_ATT _IOWR(UVIO_TYPE_UVC, 0x01, struct uvio_ioctl_cb)
> +#define UVIO_IOCTL_QUI _IOWR(UVIO_TYPE_UVC, 0x02, struct uvio_ioctl_cb)
>   
>   #endif  /* __S390X_ASM_UVDEVICE_H */
> diff --git a/drivers/s390/char/uvdevice.c b/drivers/s390/char/uvdevice.c
> index b720dc8d0bd9..cfce8c5999e6 100644
> --- a/drivers/s390/char/uvdevice.c
> +++ b/drivers/s390/char/uvdevice.c
> @@ -31,6 +31,55 @@
>   #include <asm/uvdevice.h>
>   #include <asm/uv.h>
>   
> +/**
> + * uvio_qui() - Perform a Query Ultravisor Information UVC.
> + *
> + * uv_ioctl: ioctl control block
> + *
> + * uvio_qui() does a Query Ultravisor Information (QUI) Ultravisor Call.
> + * It creates the uvc qui request and sends it to the Ultravisor. After that
> + * it copies the response to userspace and fills the rc and rrc of uv_ioctl
> + * uv_call with the response values of the Ultravisor.
> + *
> + * Create the UVC structure, send the UVC to UV and write the response in the ioctl struct.
> + *
> + * Return: 0 on success or a negative error code on error.
> + */
> +static int uvio_qui(struct uvio_ioctl_cb *uv_ioctl)
> +{
> +	u8 __user *user_buf_addr = (__user u8 *)uv_ioctl->argument_addr;
> +	size_t user_buf_len = uv_ioctl->argument_len;
> +	struct uv_cb_header *uvcb_qui = NULL;
> +	int ret;
> +
> +	/*
> +	 * Do not check for a too small buffer. If userspace provides a buffer
> +	 * that is too small the Ultravisor will complain.
> +	 */
> +	ret = -EINVAL;
> +	if (!user_buf_len || user_buf_len > UVIO_QUI_MAX_LEN)
> +		goto out;
> +	ret = -ENOMEM;
> +	uvcb_qui = kvzalloc(user_buf_len, GFP_KERNEL);
> +	if (!uvcb_qui)
> +		goto out;
> +	uvcb_qui->len = user_buf_len;
> +	uvcb_qui->cmd = UVC_CMD_QUI;
> +
> +	uv_call(0, (u64)uvcb_qui);
> +
> +	ret = -EFAULT;
> +	if (copy_to_user(user_buf_addr, uvcb_qui, uvcb_qui->len))
> +		goto out;
> +	uv_ioctl->uv_rc = uvcb_qui->rc;
> +	uv_ioctl->uv_rrc = uvcb_qui->rrc;
> +
> +	ret = 0;
> +out:
> +	kvfree(uvcb_qui);
> +	return ret;
> +}
> +
>   static int uvio_build_uvcb_attest(struct uv_cb_attest *uvcb_attest, u8 *arcb,
>   				  u8 *meas, u8 *add_data, struct uvio_attest *uvio_attest)
>   {
> @@ -217,6 +266,13 @@ static long uvio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>   			goto out;
>   		ret = uvio_attestation(uv_ioctl);
>   		break;
> +	case UVIO_IOCTL_QUI:
> +		ret = uvio_copy_and_check_ioctl(uv_ioctl, argp);
> +		if (ret)
> +			goto out;
> +		ret = uvio_qui(uv_ioctl);
> +		break;
> +
>   	default:
>   		ret = -ENOIOCTLCMD;
>   		break;

[PATCH v3 3/4] selftests: drivers/s390x: Add uvdevice tests

[Steffen Eiden]

Adds some selftests to test ioctl error paths of the uv-uapi.
The Kconfig S390_UV_UAPI must be selected and the Ultravisor facility
must be available. The test can be executed by non-root, however, the
uvdevice special file /dev/uv must be accessible for reading and
writing which may imply root privileges.

  ./test-uv-device
  TAP version 13
  1..6
  # Starting 6 tests from 3 test cases.
  #  RUN           uvio_fixture.att.fault_ioctl_arg ...
  #            OK  uvio_fixture.att.fault_ioctl_arg
  ok 1 uvio_fixture.att.fault_ioctl_arg
  #  RUN           uvio_fixture.att.fault_uvio_arg ...
  #            OK  uvio_fixture.att.fault_uvio_arg
  ok 2 uvio_fixture.att.fault_uvio_arg
  #  RUN           uvio_fixture.att.inval_ioctl_cb ...
  #            OK  uvio_fixture.att.inval_ioctl_cb
  ok 3 uvio_fixture.att.inval_ioctl_cb
  #  RUN           uvio_fixture.att.inval_ioctl_cmd ...
  #            OK  uvio_fixture.att.inval_ioctl_cmd
  ok 4 uvio_fixture.att.inval_ioctl_cmd
  #  RUN           attest_fixture.att_inval_request ...
  #            OK  attest_fixture.att_inval_request
  ok 5 attest_fixture.att_inval_request
  #  RUN           attest_fixture.att_inval_addr ...
  #            OK  attest_fixture.att_inval_addr
  ok 6 attest_fixture.att_inval_addr
  # PASSED: 6 / 6 tests passed.
  # Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
---
 MAINTAINERS                                   |   1 +
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/drivers/.gitignore    |   1 +
 .../selftests/drivers/s390x/uvdevice/Makefile |  22 ++
 .../selftests/drivers/s390x/uvdevice/config   |   1 +
 .../drivers/s390x/uvdevice/test_uvdevice.c    | 276 ++++++++++++++++++
 6 files changed, 302 insertions(+)
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/Makefile
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/config
 create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c

diff --git a/MAINTAINERS b/MAINTAINERS
index f32e876f45c2..7fdf0fa006db 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10582,6 +10582,7 @@ F:	arch/s390/kernel/uv.c
 F:	arch/s390/kvm/
 F:	arch/s390/mm/gmap.c
 F:	drivers/s390/char/uvdevice.c
+F:	tools/testing/selftests/drivers/s390x/uvdevice/
 F:	tools/testing/selftests/kvm/*/s390x/
 F:	tools/testing/selftests/kvm/s390x/
 
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index d08fe4cfe811..d454faf936c3 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -10,6 +10,7 @@ TARGETS += core
 TARGETS += cpufreq
 TARGETS += cpu-hotplug
 TARGETS += drivers/dma-buf
+TARGETS += drivers/s390x/uvdevice
 TARGETS += efivarfs
 TARGETS += exec
 TARGETS += filesystems
diff --git a/tools/testing/selftests/drivers/.gitignore b/tools/testing/selftests/drivers/.gitignore
index ca74f2e1c719..09e23b5afa96 100644
--- a/tools/testing/selftests/drivers/.gitignore
+++ b/tools/testing/selftests/drivers/.gitignore
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 /dma-buf/udmabuf
+/s390x/uvdevice/test_uvdevice
diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/Makefile b/tools/testing/selftests/drivers/s390x/uvdevice/Makefile
new file mode 100644
index 000000000000..5e701d2708d4
--- /dev/null
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/Makefile
@@ -0,0 +1,22 @@
+include ../../../../../build/Build.include
+
+UNAME_M := $(shell uname -m)
+
+ifneq ($(UNAME_M),s390x)
+nothing:
+.PHONY: all clean run_tests install
+.SILENT:
+else
+
+TEST_GEN_PROGS := test_uvdevice
+
+top_srcdir ?= ../../../../../..
+KSFT_KHDR_INSTALL := 1
+khdr_dir = $(top_srcdir)/usr/include
+LINUX_TOOL_ARCH_INCLUDE = $(top_srcdir)/tools/arch/$(ARCH)/include
+
+CFLAGS += -Wall -Werror -static -I$(khdr_dir) -I$(LINUX_TOOL_ARCH_INCLUDE)
+
+include ../../../lib.mk
+
+endif
diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/config b/tools/testing/selftests/drivers/s390x/uvdevice/config
new file mode 100644
index 000000000000..f28a04b99eff
--- /dev/null
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/config
@@ -0,0 +1 @@
+CONFIG_S390_UV_UAPI=y
diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
new file mode 100644
index 000000000000..ea0cdc37b44f
--- /dev/null
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  selftest for the Ultravisor UAPI device
+ *
+ *  Copyright IBM Corp. 2022
+ *  Author(s): Steffen Eiden <seiden@linux.ibm.com>
+ */
+
+#include <stdint.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+
+#include <asm/uvdevice.h>
+
+#include "../../../kselftest_harness.h"
+
+#define UV_PATH  "/dev/uv"
+#define BUFFER_SIZE 0x200
+FIXTURE(uvio_fixture) {
+	int uv_fd;
+	struct uvio_ioctl_cb uvio_ioctl;
+	uint8_t buffer[BUFFER_SIZE];
+	__u64 fault_page;
+};
+
+FIXTURE_VARIANT(uvio_fixture) {
+	unsigned long ioctl_cmd;
+	uint32_t arg_size;
+};
+
+FIXTURE_VARIANT_ADD(uvio_fixture, att) {
+	.ioctl_cmd = UVIO_IOCTL_ATT,
+	.arg_size = sizeof(struct uvio_attest),
+};
+
+FIXTURE_SETUP(uvio_fixture)
+{
+	self->uv_fd = open(UV_PATH, O_ACCMODE);
+
+	self->uvio_ioctl.argument_addr = (__u64)self->buffer;
+	self->uvio_ioctl.argument_len = variant->arg_size;
+	self->fault_page =
+		(__u64)mmap(NULL, (size_t)getpagesize(), PROT_NONE, MAP_ANONYMOUS, -1, 0);
+}
+
+FIXTURE_TEARDOWN(uvio_fixture)
+{
+	if (self->uv_fd)
+		close(self->uv_fd);
+	munmap((void *)self->fault_page, (size_t)getpagesize());
+}
+
+TEST_F(uvio_fixture, fault_ioctl_arg)
+{
+	int rc, errno_cache;
+
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, NULL);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, self->fault_page);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+}
+
+TEST_F(uvio_fixture, fault_uvio_arg)
+{
+	int rc, errno_cache;
+
+	self->uvio_ioctl.argument_addr = 0;
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+
+	self->uvio_ioctl.argument_addr = self->fault_page;
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+}
+
+/*
+ * Test to verify that IOCTLs with invalid values in the ioctl_control block
+ * are rejected.
+ */
+TEST_F(uvio_fixture, inval_ioctl_cb)
+{
+	int rc, errno_cache;
+
+	self->uvio_ioctl.argument_len = 0;
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+
+	self->uvio_ioctl.argument_len = (uint32_t)-1;
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+	self->uvio_ioctl.argument_len = variant->arg_size;
+
+	self->uvio_ioctl.flags = (uint32_t)-1;
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+	self->uvio_ioctl.flags = 0;
+
+	memset(self->uvio_ioctl.reserved14, 0xff, sizeof(self->uvio_ioctl.reserved14));
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+
+	memset(&self->uvio_ioctl, 0x11, sizeof(self->uvio_ioctl));
+	rc = ioctl(self->uv_fd, variant->ioctl_cmd, &self->uvio_ioctl);
+	ASSERT_EQ(rc, -1);
+}
+
+TEST_F(uvio_fixture, inval_ioctl_cmd)
+{
+	int rc, errno_cache;
+	uint8_t nr = _IOC_NR(variant->ioctl_cmd);
+	unsigned long cmds[] = {
+		_IOWR('a', nr, struct uvio_ioctl_cb),
+		_IOWR(UVIO_TYPE_UVC, nr, int),
+		_IO(UVIO_TYPE_UVC, nr),
+		_IOR(UVIO_TYPE_UVC, nr, struct uvio_ioctl_cb),
+		_IOW(UVIO_TYPE_UVC, nr, struct uvio_ioctl_cb),
+	};
+
+	for (size_t i = 0; i < ARRAY_SIZE(cmds); i++) {
+		rc = ioctl(self->uv_fd, cmds[i], &self->uvio_ioctl);
+		errno_cache = errno;
+		ASSERT_EQ(rc, -1);
+		ASSERT_EQ(errno_cache, ENOTTY);
+	}
+}
+
+struct test_attest_buffer {
+	uint8_t arcb[0x180];
+	uint8_t meas[64];
+	uint8_t add[32];
+};
+
+FIXTURE(attest_fixture) {
+	int uv_fd;
+	struct uvio_ioctl_cb uvio_ioctl;
+	struct uvio_attest uvio_attest;
+	struct test_attest_buffer attest_buffer;
+	__u64 fault_page;
+};
+
+FIXTURE_SETUP(attest_fixture)
+{
+	self->uv_fd = open(UV_PATH, O_ACCMODE);
+
+	self->uvio_ioctl.argument_addr = (__u64)&self->uvio_attest;
+	self->uvio_ioctl.argument_len = sizeof(self->uvio_attest);
+
+	self->uvio_attest.arcb_addr = (__u64)&self->attest_buffer.arcb;
+	self->uvio_attest.arcb_len = sizeof(self->attest_buffer.arcb);
+
+	self->uvio_attest.meas_addr = (__u64)&self->attest_buffer.meas;
+	self->uvio_attest.meas_len = sizeof(self->attest_buffer.meas);
+
+	self->uvio_attest.add_data_addr = (__u64)&self->attest_buffer.add;
+	self->uvio_attest.add_data_len = sizeof(self->attest_buffer.add);
+	self->fault_page =
+		(__u64)mmap(NULL, (size_t)getpagesize(), PROT_NONE, MAP_ANONYMOUS, -1, 0);
+}
+
+FIXTURE_TEARDOWN(attest_fixture)
+{
+	if (self->uv_fd)
+		close(self->uv_fd);
+	munmap((void *)self->fault_page, (size_t)getpagesize());
+}
+
+static void att_inval_sizes_test(uint32_t *size, uint32_t max_size, bool test_zero,
+				 struct __test_metadata *_metadata,
+				 FIXTURE_DATA(attest_fixture) *self)
+{
+	int rc, errno_cache;
+	uint32_t tmp = *size;
+
+	if (test_zero) {
+		*size = 0;
+		rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+		errno_cache = errno;
+		ASSERT_EQ(rc, -1);
+		ASSERT_EQ(errno_cache, EINVAL);
+	}
+	*size = max_size + 1;
+	rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+	*size = tmp;
+}
+
+/*
+ * Test to verify that attestation IOCTLs with invalid values in the UVIO
+ * attestation control block are rejected.
+ */
+TEST_F(attest_fixture, att_inval_request)
+{
+	int rc, errno_cache;
+
+	att_inval_sizes_test(&self->uvio_attest.add_data_len, UVIO_ATT_ADDITIONAL_MAX_LEN,
+			     false, _metadata, self);
+	att_inval_sizes_test(&self->uvio_attest.meas_len, UVIO_ATT_MEASUREMENT_MAX_LEN,
+			     true, _metadata, self);
+	att_inval_sizes_test(&self->uvio_attest.arcb_len, UVIO_ATT_ARCB_MAX_LEN,
+			     true, _metadata, self);
+
+	self->uvio_attest.reserved136 = (uint16_t)-1;
+	rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EINVAL);
+
+	memset(&self->uvio_attest, 0x11, sizeof(self->uvio_attest));
+	rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+	ASSERT_EQ(rc, -1);
+}
+
+static void att_inval_addr_test(__u64 *addr, struct __test_metadata *_metadata,
+				FIXTURE_DATA(attest_fixture) *self)
+{
+	int rc, errno_cache;
+	__u64 tmp = *addr;
+
+	*addr = 0;
+	rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+	*addr = self->fault_page;
+	rc = ioctl(self->uv_fd, UVIO_IOCTL_ATT, &self->uvio_ioctl);
+	errno_cache = errno;
+	ASSERT_EQ(rc, -1);
+	ASSERT_EQ(errno_cache, EFAULT);
+	*addr = tmp;
+}
+
+TEST_F(attest_fixture, att_inval_addr)
+{
+	att_inval_addr_test(&self->uvio_attest.arcb_addr, _metadata, self);
+	att_inval_addr_test(&self->uvio_attest.add_data_addr, _metadata, self);
+	att_inval_addr_test(&self->uvio_attest.meas_addr, _metadata, self);
+}
+
+static void __attribute__((constructor)) __constructor_order_last(void)
+{
+	if (!__constructor_order)
+		__constructor_order = _CONSTRUCTOR_ORDER_BACKWARD;
+}
+
+int main(int argc, char **argv)
+{
+	int fd = open(UV_PATH, O_ACCMODE);
+
+	if (fd < 0)
+		ksft_exit_skip("No uv-device or cannot access " UV_PATH  "\n"
+			       "Enable CONFIG_S390_UV_UAPI and check the access rights on "
+			       UV_PATH ".\n");
+	close(fd);
+	return test_harness_run(argc, argv);
+}
-- 
2.25.1

[PATCH v3 4/4] selftests: drivers/s390x: Add uvdevice QUI tests

[Steffen Eiden]

Add test variant to also verify that QUI-error paths
are working as intended.

  ./test-uv-device
  TAP version 13
  1..10
  # Starting 10 tests from 4 test cases.
  #  RUN           uvio_fixture.qui.fault_ioctl_arg ...
  #            OK  uvio_fixture.qui.fault_ioctl_arg
  ok 1 uvio_fixture.qui.fault_ioctl_arg
  #  RUN           uvio_fixture.qui.fault_uvio_arg ...
  #            OK  uvio_fixture.qui.fault_uvio_arg
  ok 2 uvio_fixture.qui.fault_uvio_arg
  #  RUN           uvio_fixture.qui.inval_ioctl_cb ...
  #            OK  uvio_fixture.qui.inval_ioctl_cb
  ok 3 uvio_fixture.qui.inval_ioctl_cb
  #  RUN           uvio_fixture.qui.inval_ioctl_cmd ...
  #            OK  uvio_fixture.qui.inval_ioctl_cmd
  ok 4 uvio_fixture.qui.inval_ioctl_cmd
  #  RUN           uvio_fixture.att.fault_ioctl_arg ...
  #            OK  uvio_fixture.att.fault_ioctl_arg
  ok 5 uvio_fixture.att.fault_ioctl_arg
  #  RUN           uvio_fixture.att.fault_uvio_arg ...
  #            OK  uvio_fixture.att.fault_uvio_arg
  ok 6 uvio_fixture.att.fault_uvio_arg
  #  RUN           uvio_fixture.att.inval_ioctl_cb ...
  #            OK  uvio_fixture.att.inval_ioctl_cb
  ok 7 uvio_fixture.att.inval_ioctl_cb
  #  RUN           uvio_fixture.att.inval_ioctl_cmd ...
  #            OK  uvio_fixture.att.inval_ioctl_cmd
  ok 8 uvio_fixture.att.inval_ioctl_cmd
  #  RUN           attest_fixture.att_inval_request ...
  #            OK  attest_fixture.att_inval_request
  ok 9 attest_fixture.att_inval_request
  #  RUN           attest_fixture.att_inval_addr ...
  #            OK  attest_fixture.att_inval_addr
  ok 10 attest_fixture.att_inval_addr
  # PASSED: 10 / 10 tests passed.
  # Totals: pass:10 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
---
 .../testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
index ea0cdc37b44f..44a6fbefc156 100644
--- a/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
@@ -30,6 +30,11 @@ FIXTURE_VARIANT(uvio_fixture) {
 	uint32_t arg_size;
 };
 
+FIXTURE_VARIANT_ADD(uvio_fixture, qui) {
+	.ioctl_cmd = UVIO_IOCTL_QUI,
+	.arg_size = BUFFER_SIZE,
+};
+
 FIXTURE_VARIANT_ADD(uvio_fixture, att) {
 	.ioctl_cmd = UVIO_IOCTL_ATT,
 	.arg_size = sizeof(struct uvio_attest),
-- 
2.25.1

Re: [PATCH v3 0/4] s390: Ultravisor device

[Janosch Frank]

On 3/4/22 15:11, Steffen Eiden wrote:
> This series adds an Ultravisor(UV) device letting the userspace send some
> Ultravisor calls to the UV. Currently two calls are supported.
> Query Ultravisor Information (QUI) and
> Receive Attestation Measurement (Attest[ation]).
> 
> The UV device is implemented as a miscdevice accepting only IOCTLs.
> The IOCTL cmd specifies the UV call and the IOCTL arg the request
> and response data depending on the UV call.
> The device driver writes the UV response in the ioctl argument data.
> 
> The 'uvdevice' does no checks on the request beside faulty userspace
> addresses, if sizes are in a sane range before allocating in kernel space,
> and other tests that prevent the system from corruption.
> Especially, no checks are made, that will be performed by the UV anyway
> (E.g. 'invalid command' in case of attestation on unsupported hardware).
> These errors are reported back to Userspace using the UV return code
> field.
> 
> The first two patches introduce the new device as a module configured to be
> compiled directly into the kernel (y) similar to the s390 SCLP and CHSH
> miscdevice modules. Patch 3&4 introduce Kselftests which verify error
> paths of the ioctl.

Please fixup the commit message in the first patch and then push patches 
#1 and #3 to devel so we get CI coverage.

For now I'd opt to not include the qui patches but please put them on a 
branch. They might prove to be useful at a later time.

> 
> v2->v3:
>     The main change is that QUI is now introduced after Attestation as we
>     might not want pick it. Also the Kselftest patch is splitted into
>     Attestation and QUI so that they can be picked without requiring
>     QUI support of the uvdevice.
> 
>    * dropped the Kconfig dependency
>    * reorganized the series:
>      - Patch 1 now covers the introduction of the uvdevice and Attestation
>      - Patch 2 adds QUI to uvdevice
>      - Patch 3/4 add Kselftests for Attestation and QUI
>    * fixed some nits
>    * added some comments
> 
> v1->v2:
>    * ioctl returns -ENOIOCTLCMD in case of a invalid ioctl command
>    * streamlined reserved field test
>    * default Kconfig is y instead of m
>    * improved selftest documentation
> 
> Steffen Eiden (4):
>    drivers/s390/char: Add Ultravisor io device
>    drivers/s390/char: Add Query Ultravisor Information to uvdevice
>    selftests: drivers/s390x: Add uvdevice tests
>    selftests: drivers/s390x: Add uvdevice  QUI tests
> 
>   MAINTAINERS                                   |   3 +
>   arch/s390/include/asm/uv.h                    |  23 +-
>   arch/s390/include/uapi/asm/uvdevice.h         |  53 +++
>   drivers/s390/char/Kconfig                     |  10 +
>   drivers/s390/char/Makefile                    |   1 +
>   drivers/s390/char/uvdevice.c                  | 320 ++++++++++++++++++
>   tools/testing/selftests/Makefile              |   1 +
>   tools/testing/selftests/drivers/.gitignore    |   1 +
>   .../selftests/drivers/s390x/uvdevice/Makefile |  22 ++
>   .../selftests/drivers/s390x/uvdevice/config   |   1 +
>   .../drivers/s390x/uvdevice/test_uvdevice.c    | 281 +++++++++++++++
>   11 files changed, 715 insertions(+), 1 deletion(-)
>   create mode 100644 arch/s390/include/uapi/asm/uvdevice.h
>   create mode 100644 drivers/s390/char/uvdevice.c
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/Makefile
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/config
>   create mode 100644 tools/testing/selftests/drivers/s390x/uvdevice/test_uvdevice.c
>