Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx>
@@ -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@xxxxxxxxxxxxx>
+ */
+#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@xxxxxxxxxxxxx>
+ *
+ * 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");
