fTPM: firmware TPM running in TEE

This patch adds support for a software-only implementation of a TPM running in TEE.

There is extensive documentation of the design here:
https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ .

As well as reference code for the firmware available here:
https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM

Signed-off-by Thirupathaiah Annapureddy <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

---
 drivers/char/tpm/Kconfig        |   5 +
 drivers/char/tpm/Makefile       |   1 +
 drivers/char/tpm/tpm_ftpm_tee.c | 380 ++++++++++++++++++++++++++++++++
 drivers/char/tpm/tpm_ftpm_tee.h |  40 ++++
 4 files changed, 426 insertions(+)
 create mode 100644 drivers/char/tpm/tpm_ftpm_tee.c
 create mode 100644 drivers/char/tpm/tpm_ftpm_tee.h

drivers/char/tpm/Kconfig +5 -0

index f3e4bc490cf05..8bc9a56cade14 100644
@@ -163,6 +163,11 @@ config TCG_VTPM_PROXY
          /dev/vtpmX and a server-side file descriptor on which the vTPM
          can receive commands.
 
+config TCG_FTPM_TEE
+       tristate "TEE based fTPM Interface"
+       depends on TEE && OPTEE
+       ---help---
+         This driver proxies for fTPM running in TEE
 
 source "drivers/char/tpm/st33zp24/Kconfig"
 endif # TCG_TPM

drivers/char/tpm/Makefile +1 -0

index a01c4cab902a6..c354cdff9c625 100644
@@ -33,3 +33,4 @@ obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/
 obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
 obj-$(CONFIG_TCG_CRB) += tpm_crb.o
 obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
+obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o

drivers/char/tpm/tpm_ftpm_tee.c new file +258 -0

new file mode 100644
index 0000000000000..f926b1287988b
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation
+ *
+ * Implements a firmware TPM as described here:
+ * https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/
+ *
+ * A reference implementation is available here:
+ * https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM
+ */
+
+#include <linux/acpi.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/tee_drv.h>
+#include <linux/tpm.h>
+#include <linux/uuid.h>
+
+#include "tpm.h"
+#include "tpm_ftpm_tee.h"
+
+#define DRIVER_NAME "ftpm-tee"
+
+/*
+ * TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896
+ *
+ * Randomly generated, and must correspond to the GUID on the TA side.
+ * Defined here in the reference implementation:
+ * https://github.com/microsoft/ms-tpm-20-ref/blob/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM/include/fTPM.h#L42
+ */
+
+static const uuid_t ftpm_ta_uuid =
+       UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4,
+                 0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96);
+
+/**
+ * ftpm_tee_tpm_op_recv - retrieve fTPM response.
+ *
+ * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h.
+ * @buf: the buffer to store data.
+ * @count: the number of bytes to read.
+ *
+ * Return:
+ *     In case of success the number of bytes received.
+ *     On failure, -errno.
+ */
+static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
+{
+       struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
+       size_t len;
+
+       len = pvt_data->resp_len;
+       if (count < len) {
+               dev_err(&chip->dev,
+                       "%s:Invalid size in recv: count=%zd, resp_len=%zd\n",
+                       __func__, count, len);
+               return -EIO;
+       }
+
+       memcpy(buf, pvt_data->resp_buf, len);
+       pvt_data->resp_len = 0;
+
+       return len;
+}
+
+/**
+ * ftpm_tee_tpm_op_send - send TPM commands through the TEE shared memory.
+ *
+ * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h
+ * @buf: the buffer to send.
+ * @len: the number of bytes to send.
+ *
+ * Return:
+ *     In case of success, returns 0.
+ *     On failure, -errno
+ */
+static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len)
+{
+       struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
+       size_t resp_len;
+       int rc;
+       u8 *temp_buf;
+       struct tpm_header *resp_header;
+       struct tee_ioctl_invoke_arg transceive_args;
+       struct tee_param command_params[4];
+       struct tee_shm *shm = pvt_data->shm;
+
+       if (len > MAX_COMMAND_SIZE) {
+               dev_err(&chip->dev,
+                       "%s:len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n",
+                       __func__, len);
+               return -EIO;
+       }
+
+       memset(&transceive_args, 0, sizeof(transceive_args));
+       memset(command_params, 0, sizeof(command_params));
+       pvt_data->resp_len = 0;
+
+       /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */
+       transceive_args = (struct tee_ioctl_invoke_arg) {
+               .func = FTPM_OPTEE_TA_SUBMIT_COMMAND,
+               .session = pvt_data->session,
+               .num_params = 4,
+       };
+
+       /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */
+       command_params[0] = (struct tee_param) {
+               .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
+               .u.memref = {
+                       .shm = shm,
+                       .size = len,
+                       .shm_offs = 0,
+               },
+       };
+
+       temp_buf = tee_shm_get_va(shm, 0);
+       if (IS_ERR(temp_buf)) {
+               dev_err(&chip->dev, "%s:tee_shm_get_va failed for transmit\n",
+                       __func__);
+               return PTR_ERR(temp_buf);
+       }
+       memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE));
+
+       memcpy(temp_buf, buf, len);
+
+       command_params[1] = (struct tee_param) {
+               .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT,
+               .u.memref = {
+                       .shm = shm,
+                       .size = MAX_RESPONSE_SIZE,
+                       .shm_offs = MAX_COMMAND_SIZE,
+               },
+       };
+
+       rc = tee_client_invoke_func(pvt_data->ctx, &transceive_args,
+                                       command_params);
+       if ((rc < 0) || (transceive_args.ret != 0)) {
+               dev_err(&chip->dev, "%s:SUBMIT_COMMAND invoke error: 0x%x\n",
+                       __func__, transceive_args.ret);
+               return (rc < 0) ? rc : transceive_args.ret;
+       }
+
+       temp_buf = tee_shm_get_va(shm, command_params[1].u.memref.shm_offs);
+       if (IS_ERR(temp_buf)) {
+               dev_err(&chip->dev, "%s:tee_shm_get_va failed for receive\n",
+                       __func__);
+               return PTR_ERR(temp_buf);
+       }
+
+       resp_header = (struct tpm_header *)temp_buf;
+       resp_len = be32_to_cpu(resp_header->length);
+
+       /* sanity check resp_len */
+       if (resp_len < TPM_HEADER_SIZE) {
+               dev_err(&chip->dev, "%s:tpm response header too small\n",
+                       __func__);
+               return -EIO;
+       }
+       if (resp_len > MAX_RESPONSE_SIZE) {
+               dev_err(&chip->dev,
+                       "%s:resp_len=%zd exceeds MAX_RESPONSE_SIZE\n",
+                       __func__, resp_len);
+               return -EIO;
+       }
+
+       /* sanity checks look good, cache the response */
+       memcpy(pvt_data->resp_buf, temp_buf, resp_len);
+       pvt_data->resp_len = resp_len;
+
+       return 0;
+}
+
+static void ftpm_tee_tpm_op_cancel(struct tpm_chip *chip)
+{
+       /* not supported */
+}
+
+static u8 ftpm_tee_tpm_op_status(struct tpm_chip *chip)
+{
+       return 0;
+}
+
+static bool ftpm_tee_tpm_req_canceled(struct tpm_chip *chip, u8 status)
+{
+       return 0;
+}
+
+static const struct tpm_class_ops ftpm_tee_tpm_ops = {
+       .flags = TPM_OPS_AUTO_STARTUP,
+       .recv = ftpm_tee_tpm_op_recv,
+       .send = ftpm_tee_tpm_op_send,
+       .cancel = ftpm_tee_tpm_op_cancel,
+       .status = ftpm_tee_tpm_op_status,
+       .req_complete_mask = 0,
+       .req_complete_val = 0,
+       .req_canceled = ftpm_tee_tpm_req_canceled,
+};
+
+/*
+ * Check whether this driver supports the fTPM TA in the TEE instance
+ * represented by the params (ver/data) to this function.
+ */
+static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data)
+{
+       /*
+        * Currently this driver only support GP Complaint OPTEE based fTPM TA
+        */
+       if ((ver->impl_id == TEE_IMPL_ID_OPTEE) &&
+               (ver->gen_caps & TEE_GEN_CAP_GP))
+               return 1;
+       else
+               return 0;
+}
+
+/*
+ * Undo what has been done in ftpm_tee_probe
+ */
+static void ftpm_tee_deinit(struct ftpm_tee_private *pvt_data)
+{
+       /* Release the chip */
+       tpm_chip_unregister(pvt_data->chip);
+
+       /* frees chip */
+       if (pvt_data->chip)
+               put_device(&pvt_data->chip->dev);
+
+       if (pvt_data->ctx) {
+               /* Free the shared memory pool */
+               tee_shm_free(pvt_data->shm);
+
+               /* close the existing session with fTPM TA*/
+               tee_client_close_session(pvt_data->ctx, pvt_data->session);
+
+               /* close the context with TEE driver */
+               tee_client_close_context(pvt_data->ctx);
+       }
+
+       /* memory allocated with devm_kzalloc() is freed automatically */
+}
+
+/**
+ * ftpm_tee_probe - initialize the fTPM
+ * @pdev: the platform_device description.
+ *
+ * Return:
+ *     On success, 0. On failure, -errno.
+ */
+static int ftpm_tee_probe(struct platform_device *pdev)
+{
+       int rc;
+       struct tpm_chip *chip;
+       struct device *dev = &pdev->dev;
+       struct ftpm_tee_private *pvt_data = NULL;
+       struct tee_ioctl_open_session_arg sess_arg;
+
+       pvt_data = devm_kzalloc(dev, sizeof(struct ftpm_tee_private),
+                               GFP_KERNEL);

drivers/char/tpm/tpm_ftpm_tee.c new file +112 -0

+               return -EPROBE_DEFER;
+       }
+
+       /* Open a session with fTPM TA */
+       memset(&sess_arg, 0, sizeof(sess_arg));
+       memcpy(sess_arg.uuid, ftpm_ta_uuid.b, TEE_IOCTL_UUID_LEN);
+       sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
+       sess_arg.num_params = 0;
+
+       rc = tee_client_open_session(pvt_data->ctx, &sess_arg, NULL);
+       if ((rc < 0) || (sess_arg.ret != 0)) {
+               dev_err(dev, "%s:tee_client_open_session failed, err=%x\n",
+                       __func__, sess_arg.ret);
+               rc = -EINVAL;
+               goto out_tee_session;
+       }
+       pvt_data->session = sess_arg.session;
+
+       /* Allocate dynamic shared memory with fTPM TA */
+       pvt_data->shm = tee_shm_alloc(pvt_data->ctx,
+                               (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE),
+                               TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
+       if (IS_ERR(pvt_data->shm)) {
+               dev_err(dev, "%s:tee_shm_alloc failed\n", __func__);
+               rc = -ENOMEM;
+               goto out_shm_alloc;
+       }
+
+       /* Allocate new struct tpm_chip instance */
+       chip = tpm_chip_alloc(dev, &ftpm_tee_tpm_ops);
+       if (IS_ERR(chip)) {
+               dev_err(dev, "%s:tpm_chip_alloc failed\n", __func__);
+               rc = PTR_ERR(chip);
+               goto out_chip_alloc;
+       }
+
+       pvt_data->chip = chip;
+       pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2;
+
+       /* Create a character device for the fTPM */
+       rc = tpm_chip_register(pvt_data->chip);
+       if (rc) {
+               dev_err(dev, "%s:tpm_chip_register failed with rc=%d\n",
+                       __func__, rc);
+               goto out_chip;
+       }
+
+       return 0;
+
+out_chip:
+       put_device(&pvt_data->chip->dev);
+out_chip_alloc:
+       tee_shm_free(pvt_data->shm);
+out_shm_alloc:
+       tee_client_close_session(pvt_data->ctx, pvt_data->session);
+out_tee_session:
+       tee_client_close_context(pvt_data->ctx);
+
+       return rc;
+}
+
+/**
+ * ftpm_tee_remove - remove the TPM device
+ * @pdev: the platform_device description.
+ *
+ * Return:
+ *     0 in case of success.
+ */
+static int ftpm_tee_remove(struct platform_device *pdev)
+{
+       struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
+
+       /* Release the chip */
+       tpm_chip_unregister(pvt_data->chip);
+
+       /* frees chip */
+       put_device(&pvt_data->chip->dev);
+
+       /* Free the shared memory pool */
+       tee_shm_free(pvt_data->shm);
+
+       /* close the existing session with fTPM TA*/
+       tee_client_close_session(pvt_data->ctx, pvt_data->session);
+
+       /* close the context with TEE driver */
+       tee_client_close_context(pvt_data->ctx);
+
+        /* memory allocated with devm_kzalloc() is freed automatically */
+
+       return 0;
+}
+
+static const struct of_device_id of_ftpm_tee_ids[] = {
+       { .compatible = "microsoft,ftpm" },
+       { }
+};
+MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids);
+
+static struct platform_driver ftpm_tee_driver = {
+       .driver = {
+               .name = DRIVER_NAME,
+               .of_match_table = of_match_ptr(of_ftpm_tee_ids),
+       },
+       .probe = ftpm_tee_probe,
+       .remove = ftpm_tee_remove,
+};
+
+module_platform_driver(ftpm_tee_driver);
+
+MODULE_AUTHOR("Thirupathaiah Annapureddy <[email protected]>");
+MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE");
+MODULE_LICENSE("GPL v2");

drivers/char/tpm/tpm_ftpm_tee.h new file +40 -1

new file mode 100644
index 0000000000000..b09ee7be45459
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) Microsoft Corporation
+ */
+
+#ifndef __TPM_FTPM_TEE_H__
+#define __TPM_FTPM_TEE_H__
+
+#include <linux/tee_drv.h>
+#include <linux/tpm.h>
+#include <linux/uuid.h>
+
+/* The TAFs ID implemented in this TA */
+#define FTPM_OPTEE_TA_SUBMIT_COMMAND  (0)
+#define FTPM_OPTEE_TA_EMULATE_PPI     (1)
+
+/* max. buffer size supported by fTPM  */
+#define  MAX_COMMAND_SIZE       4096
+#define  MAX_RESPONSE_SIZE      4096
+
+/**
+ * struct ftpm_tee_private - fTPM's private data
+ * @chip:     struct tpm_chip instance registered with tpm framework.
+ * @state:    internal state
+ * @session:  fTPM TA session identifier.
+ * @resp_len: cached response buffer length.
+ * @resp_buf: cached response buffer.
+ * @ctx:      TEE context handler.
+ * @shm:      Memory pool shared with fTPM TA in TEE.
+ */
+struct ftpm_tee_private {
+       struct tpm_chip *chip;
+       u32 session;
+       size_t resp_len;
+       u8 resp_buf[MAX_RESPONSE_SIZE];
+       struct tee_context *ctx;
+       struct tee_shm *shm;
+};
+
+#endif /* __TPM_FTPM_TEE_H__ */
--

2.20.1

drivers/char/tpm/tpm_ftpm_tee.c line 268

Quoted 5 lines · Sasha Levin

drivers/char/tpm/tpm_ftpm_tee.c new file +5 -0

+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Module built with "CONFIG_TCG_FTPM_TEE=y"

[    1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed

Quoted 7 lines · Sumit Garg

Quoted 5 lines · Sasha Levin

drivers/char/tpm/tpm_ftpm_tee.c new file +5 -0

+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Quoted 2 lines

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Yes, this was all functionally tested.

Why is this error message misleading? I'd be happy to fix it.

Quoted 7 lines

Module built with "CONFIG_TCG_FTPM_TEE=y"

[    1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed

Does the TEE have the fTPM implementation and such? Could you provide details about your testing environment (hardware, fTPM verions, etc)?

--
Thanks,
Sasha

Quoted 9 lines · Sasha Levin

Quoted 7 lines · Sumit Garg

Quoted 5 lines · Sasha Levin

drivers/char/tpm/tpm_ftpm_tee.c new file +5 -0

+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Quoted 4 lines

Quoted 2 lines

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Yes, this was all functionally tested.

Can you share your build instructions and testing approach?

Quoted 10 lines · Sumit Garg

Quoted 9 lines · Sasha Levin

Quoted 7 lines · Sumit Garg

Quoted 5 lines · Sasha Levin

drivers/char/tpm/tpm_ftpm_tee.c new file +5 -0

+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Quoted 4 lines

Quoted 4 lines

Quoted 2 lines

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Yes, this was all functionally tested.

Quoted 1 line

Can you share your build instructions and testing approach?

Yes: it looks like you got all the kernel bits, but not the firmware. There are instructions for it here: https://github.com/microsoft/ms-tpm-20-ref

Once it's running, you can test it by running your favorite TPM usecases through /dev/tpm0.

--
Thanks,
Sasha

Quoted 9 lines · Sasha Levin

Quoted 7 lines · Sumit Garg

Quoted 5 lines · Sasha Levin

drivers/char/tpm/tpm_ftpm_tee.c new file +5 -0

+       /* Open context with TEE driver */
+       pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
+                                               NULL);
+       if (IS_ERR(pvt_data->ctx)) {
+               dev_err(dev, "%s:tee_client_open_context failed\n", __func__);

Quoted 4 lines

Quoted 2 lines

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Yes, this was all functionally tested.

Can you share your build instructions and testing approach?

Quoted 2 lines

Why is this error message misleading? I'd be happy to fix it.

IIUC, here you are trying to resolve dependency with OP-TEE driver using "-EPROBE_DEFER". So user shouldn't be prompted with error messages until OP-TEE driver comes up.

BTW, for me this OP-TEE driver dependency seems not to work, boot is simply stuck waiting for device. Probably the reason being this fTPM driver is a platform driver and OP-TEE NOT a platform driver.

Quoted 11 lines

Quoted 7 lines

Module built with "CONFIG_TCG_FTPM_TEE=y"

[    1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed

Does the TEE have the fTPM implementation and such? Could you provide details about your testing environment (hardware, fTPM verions, etc)?

I just did a sanity check on my arm64 machine (Developerbox), just adding following DT node and enabled CONFIG_TCG_FTPM_TEE=y:

(quoted diff) +3 -0

+    tpm@0 {
+        compatible = "microsoft,ftpm";
+    };

Basically with no fTPM TA, I expected the driver to fail during "tee_client_open_session()" call with TA not found error and boot should continue. But it fails during "tee_client_open_context()" which opens a context with OP-TEE driver and has nothing to do with fTPM TA.

-Sumit

Quoted 3 lines

--
Thanks,
Sasha

Is this well tested? I see this misleading error multiple times as follows although TEE driver works pretty well.

Module built with "CONFIG_TCG_FTPM_TEE=y"

[    1.436878] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.509471] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.517268] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed
[    1.525596] ftpm-tee tpm@0: ftpm_tee_probe:tee_client_open_context failed

-Sumit

This patch adds basic documentation to describe the new fTPM driver.

Signed-off-by Sasha Levin <[email protected]>

Signed-off-by Sasha Levin (Microsoft) <[email protected]>

---
 Documentation/security/tpm/index.rst        |  1 +
 Documentation/security/tpm/tpm_ftpm_tee.rst | 31 +++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst

Documentation/security/tpm/tpm_ftpm_tee.rst new file +5 -0

new file mode 100644
index 0000000000000..29c2f8b5ed100
@@ -0,0 +1,31 @@
+=============================================
+Firmware TPM Driver
+=============================================
+
+| Authors:

Documentation/security/tpm/tpm_ftpm_tee.rst new file +1 -0

+through this device.

Changes since v3:

- Address comments by Jarkko Sakkinen
- Address comments by Igor Opaniuk

Sasha Levin (2):
fTPM: firmware TPM running in TEE
fTPM: add documentation for ftpm driver

Quoted 5 lines · Sasha Levin

Changes since v3:

- Address comments by Jarkko Sakkinen
- Address comments by Igor Opaniuk

Quoted 3 lines

Sasha Levin (2):
fTPM: firmware TPM running in TEE
fTPM: add documentation for ftpm driver

I think patches start to look proper but I wonder can anyone test these? I don't think before that I can merge these.

Quoted 6 lines · Jarkko Sakkinen

Quoted 5 lines · Sasha Levin

Changes since v3:

- Address comments by Jarkko Sakkinen
- Address comments by Igor Opaniuk

Quoted 6 lines

Quoted 3 lines

Sasha Levin (2):
fTPM: firmware TPM running in TEE
fTPM: add documentation for ftpm driver

I think patches start to look proper but I wonder can anyone test these? I don't think before that I can merge these.

They're all functionally tested by us on actual hardware before being sent out.

The reference implementation is open and being kept updated, and an interested third party should be able to verify the correctness of these patches. However, it doesn't look like there's an interested third party given that these patches have been out for a few months now.