diff options
Diffstat (limited to 'drivers/char/tpm')
| -rw-r--r-- | drivers/char/tpm/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/char/tpm/Makefile | 1 | ||||
| -rw-r--r-- | drivers/char/tpm/eventlog/tpm1.c | 7 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm_crb_ffa.c | 74 | ||||
| -rw-r--r-- | drivers/char/tpm/tpm_svsm.c | 125 |
5 files changed, 189 insertions, 28 deletions
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig index fe4f3a609934..dddd702b2454 100644 --- a/drivers/char/tpm/Kconfig +++ b/drivers/char/tpm/Kconfig @@ -234,5 +234,15 @@ config TCG_FTPM_TEE help This driver proxies for firmware TPM running in TEE. +config TCG_SVSM + tristate "SNP SVSM vTPM interface" + depends on AMD_MEM_ENCRYPT + help + This is a driver for the AMD SVSM vTPM protocol that a SEV-SNP guest + OS can use to discover and talk to a vTPM emulated by the Secure VM + Service Module (SVSM) in the guest context, but at a more privileged + level (usually VMPL0). To compile this driver as a module, choose M + here; the module will be called tpm_svsm. + source "drivers/char/tpm/st33zp24/Kconfig" endif # TCG_TPM diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile index 2b004df8c04b..9de1b3ea34a9 100644 --- a/drivers/char/tpm/Makefile +++ b/drivers/char/tpm/Makefile @@ -45,3 +45,4 @@ obj-$(CONFIG_TCG_CRB) += tpm_crb.o obj-$(CONFIG_TCG_ARM_CRB_FFA) += tpm_crb_ffa.o obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o +obj-$(CONFIG_TCG_SVSM) += tpm_svsm.o diff --git a/drivers/char/tpm/eventlog/tpm1.c b/drivers/char/tpm/eventlog/tpm1.c index 12ee42a31c71..e7913b2853d5 100644 --- a/drivers/char/tpm/eventlog/tpm1.c +++ b/drivers/char/tpm/eventlog/tpm1.c @@ -257,11 +257,8 @@ static int tpm1_ascii_bios_measurements_show(struct seq_file *m, void *v) (unsigned char *)(v + sizeof(struct tcpa_event)); eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL); - if (!eventname) { - printk(KERN_ERR "%s: ERROR - No Memory for event name\n ", - __func__); - return -EFAULT; - } + if (!eventname) + return -ENOMEM; /* 1st: PCR */ seq_printf(m, "%2d ", do_endian_conversion(event->pcr_index)); diff --git a/drivers/char/tpm/tpm_crb_ffa.c b/drivers/char/tpm/tpm_crb_ffa.c index 3169a87a56b6..4ead61f01299 100644 --- a/drivers/char/tpm/tpm_crb_ffa.c +++ b/drivers/char/tpm/tpm_crb_ffa.c @@ -38,9 +38,11 @@ * messages. * * All requests with FFA_MSG_SEND_DIRECT_REQ and FFA_MSG_SEND_DIRECT_RESP - * are using the AArch32 SMC calling convention with register usage as - * defined in FF-A specification: - * w0: Function ID (0x8400006F or 0x84000070) + * are using the AArch32 or AArch64 SMC calling convention with register usage + * as defined in FF-A specification: + * w0: Function ID + * -for 32-bit: 0x8400006F or 0x84000070 + * -for 64-bit: 0xC400006F or 0xC4000070 * w1: Source/Destination IDs * w2: Reserved (MBZ) * w3-w7: Implementation defined, free to be used below @@ -68,7 +70,8 @@ #define CRB_FFA_GET_INTERFACE_VERSION 0x0f000001 /* - * Return information on a given feature of the TPM service + * Notifies the TPM service that a TPM command or TPM locality request is + * ready to be processed, and allows the TPM service to process it. * Call register usage: * w3: Not used (MBZ) * w4: TPM service function ID, CRB_FFA_START @@ -105,7 +108,10 @@ struct tpm_crb_ffa { u16 minor_version; /* lock to protect sending of FF-A messages: */ struct mutex msg_data_lock; - struct ffa_send_direct_data direct_msg_data; + union { + struct ffa_send_direct_data direct_msg_data; + struct ffa_send_direct_data2 direct_msg_data2; + }; }; static struct tpm_crb_ffa *tpm_crb_ffa; @@ -185,18 +191,34 @@ static int __tpm_crb_ffa_send_recieve(unsigned long func_id, msg_ops = tpm_crb_ffa->ffa_dev->ops->msg_ops; - memset(&tpm_crb_ffa->direct_msg_data, 0x00, - sizeof(struct ffa_send_direct_data)); - - tpm_crb_ffa->direct_msg_data.data1 = func_id; - tpm_crb_ffa->direct_msg_data.data2 = a0; - tpm_crb_ffa->direct_msg_data.data3 = a1; - tpm_crb_ffa->direct_msg_data.data4 = a2; + if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) { + memset(&tpm_crb_ffa->direct_msg_data2, 0x00, + sizeof(struct ffa_send_direct_data2)); + + tpm_crb_ffa->direct_msg_data2.data[0] = func_id; + tpm_crb_ffa->direct_msg_data2.data[1] = a0; + tpm_crb_ffa->direct_msg_data2.data[2] = a1; + tpm_crb_ffa->direct_msg_data2.data[3] = a2; + + ret = msg_ops->sync_send_receive2(tpm_crb_ffa->ffa_dev, + &tpm_crb_ffa->direct_msg_data2); + if (!ret) + ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data2.data[0]); + } else { + memset(&tpm_crb_ffa->direct_msg_data, 0x00, + sizeof(struct ffa_send_direct_data)); + + tpm_crb_ffa->direct_msg_data.data1 = func_id; + tpm_crb_ffa->direct_msg_data.data2 = a0; + tpm_crb_ffa->direct_msg_data.data3 = a1; + tpm_crb_ffa->direct_msg_data.data4 = a2; + + ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev, + &tpm_crb_ffa->direct_msg_data); + if (!ret) + ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data.data1); + } - ret = msg_ops->sync_send_receive(tpm_crb_ffa->ffa_dev, - &tpm_crb_ffa->direct_msg_data); - if (!ret) - ret = tpm_crb_ffa_to_linux_errno(tpm_crb_ffa->direct_msg_data.data1); return ret; } @@ -231,8 +253,13 @@ int tpm_crb_ffa_get_interface_version(u16 *major, u16 *minor) rc = __tpm_crb_ffa_send_recieve(CRB_FFA_GET_INTERFACE_VERSION, 0x00, 0x00, 0x00); if (!rc) { - *major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); - *minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); + if (ffa_partition_supports_direct_req2_recv(tpm_crb_ffa->ffa_dev)) { + *major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data2.data[1]); + *minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data2.data[1]); + } else { + *major = CRB_FFA_MAJOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); + *minor = CRB_FFA_MINOR_VERSION(tpm_crb_ffa->direct_msg_data.data2); + } } return rc; @@ -277,8 +304,9 @@ static int tpm_crb_ffa_probe(struct ffa_device *ffa_dev) tpm_crb_ffa = ERR_PTR(-ENODEV); // set tpm_crb_ffa so we can detect probe failure - if (!ffa_partition_supports_direct_recv(ffa_dev)) { - pr_err("TPM partition doesn't support direct message receive.\n"); + if (!ffa_partition_supports_direct_recv(ffa_dev) && + !ffa_partition_supports_direct_req2_recv(ffa_dev)) { + dev_warn(&ffa_dev->dev, "partition doesn't support direct message receive.\n"); return -EINVAL; } @@ -299,17 +327,17 @@ static int tpm_crb_ffa_probe(struct ffa_device *ffa_dev) rc = tpm_crb_ffa_get_interface_version(&tpm_crb_ffa->major_version, &tpm_crb_ffa->minor_version); if (rc) { - pr_err("failed to get crb interface version. rc:%d", rc); + dev_err(&ffa_dev->dev, "failed to get crb interface version. rc:%d\n", rc); goto out; } - pr_info("ABI version %u.%u", tpm_crb_ffa->major_version, + dev_info(&ffa_dev->dev, "ABI version %u.%u\n", tpm_crb_ffa->major_version, tpm_crb_ffa->minor_version); if (tpm_crb_ffa->major_version != CRB_FFA_VERSION_MAJOR || (tpm_crb_ffa->minor_version > 0 && tpm_crb_ffa->minor_version < CRB_FFA_VERSION_MINOR)) { - pr_err("Incompatible ABI version"); + dev_warn(&ffa_dev->dev, "Incompatible ABI version\n"); goto out; } diff --git a/drivers/char/tpm/tpm_svsm.c b/drivers/char/tpm/tpm_svsm.c new file mode 100644 index 000000000000..4280edf427d6 --- /dev/null +++ b/drivers/char/tpm/tpm_svsm.c @@ -0,0 +1,125 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2025 Red Hat, Inc. All Rights Reserved. + * + * Driver for the vTPM defined by the AMD SVSM spec [1]. + * + * The specification defines a protocol that a SEV-SNP guest OS can use to + * discover and talk to a vTPM emulated by the Secure VM Service Module (SVSM) + * in the guest context, but at a more privileged level (usually VMPL0). + * + * [1] "Secure VM Service Module for SEV-SNP Guests" + * Publication # 58019 Revision: 1.00 + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/platform_device.h> +#include <linux/tpm_svsm.h> + +#include <asm/sev.h> + +#include "tpm.h" + +struct tpm_svsm_priv { + void *buffer; +}; + +static int tpm_svsm_send(struct tpm_chip *chip, u8 *buf, size_t len) +{ + struct tpm_svsm_priv *priv = dev_get_drvdata(&chip->dev); + int ret; + + ret = svsm_vtpm_cmd_request_fill(priv->buffer, 0, buf, len); + if (ret) + return ret; + + /* + * The SVSM call uses the same buffer for the command and for the + * response, so after this call, the buffer will contain the response + * that can be used by .recv() op. + */ + return snp_svsm_vtpm_send_command(priv->buffer); +} + +static int tpm_svsm_recv(struct tpm_chip *chip, u8 *buf, size_t len) +{ + struct tpm_svsm_priv *priv = dev_get_drvdata(&chip->dev); + + /* + * The internal buffer contains the response after we send the command + * to SVSM. + */ + return svsm_vtpm_cmd_response_parse(priv->buffer, buf, len); +} + +static struct tpm_class_ops tpm_chip_ops = { + .flags = TPM_OPS_AUTO_STARTUP, + .recv = tpm_svsm_recv, + .send = tpm_svsm_send, +}; + +static int __init tpm_svsm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct tpm_svsm_priv *priv; + struct tpm_chip *chip; + int err; + + priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + /* + * The maximum buffer supported is one page (see SVSM_VTPM_MAX_BUFFER + * in tpm_svsm.h). + */ + priv->buffer = (void *)devm_get_free_pages(dev, GFP_KERNEL, 0); + if (!priv->buffer) + return -ENOMEM; + + chip = tpmm_chip_alloc(dev, &tpm_chip_ops); + if (IS_ERR(chip)) + return PTR_ERR(chip); + + dev_set_drvdata(&chip->dev, priv); + + err = tpm2_probe(chip); + if (err) + return err; + + err = tpm_chip_register(chip); + if (err) + return err; + + dev_info(dev, "SNP SVSM vTPM %s device\n", + (chip->flags & TPM_CHIP_FLAG_TPM2) ? "2.0" : "1.2"); + + return 0; +} + +static void __exit tpm_svsm_remove(struct platform_device *pdev) +{ + struct tpm_chip *chip = platform_get_drvdata(pdev); + + tpm_chip_unregister(chip); +} + +/* + * tpm_svsm_remove() lives in .exit.text. For drivers registered via + * module_platform_driver_probe() this is ok because they cannot get unbound + * at runtime. So mark the driver struct with __refdata to prevent modpost + * triggering a section mismatch warning. + */ +static struct platform_driver tpm_svsm_driver __refdata = { + .remove = __exit_p(tpm_svsm_remove), + .driver = { + .name = "tpm-svsm", + }, +}; + +module_platform_driver_probe(tpm_svsm_driver, tpm_svsm_probe); + +MODULE_DESCRIPTION("SNP SVSM vTPM Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:tpm-svsm"); |