From: Sami Mujawar <sami.mujawar@arm.com> mainline inclusion from mainline-v6.13-rc1 commit 7999edc484ca376f803562edb2d43ec921642c2a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IBWQ24 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Introduce an arm-cca-guest driver that registers with the configfs-tsm module to provide user interfaces for retrieving an attestation token. When a new report is requested the arm-cca-guest driver invokes the appropriate RSI interfaces to query an attestation token. The steps to retrieve an attestation token are as follows: 1. Mount the configfs filesystem if not already mounted mount -t configfs none /sys/kernel/config 2. Generate an attestation token report=/sys/kernel/config/tsm/report/report0 mkdir $report dd if=/dev/urandom bs=64 count=1 > $report/inblob hexdump -C $report/outblob rmdir $report Signed-off-by: Sami Mujawar <sami.mujawar@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Steven Price <steven.price@arm.com> Reviewed-by: Gavin Shan <gshan@redhat.com> Link: https://lore.kernel.org/r/20241017131434.40935-11-steven.price@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Conflicts: drivers/virt/coco/Kconfig drivers/virt/coco/Makefile [The commit be5ee944496f8 ("driver/virt/coco: Add HYGON CSV Guest dirver.") adds csv-guest files resulting in context conflicts] Signed-off-by: Cai Xinchen <caixinchen1@huawei.com> --- drivers/virt/coco/Kconfig | 2 + drivers/virt/coco/Makefile | 1 + drivers/virt/coco/arm-cca-guest/Kconfig | 11 + drivers/virt/coco/arm-cca-guest/Makefile | 2 + .../virt/coco/arm-cca-guest/arm-cca-guest.c | 224 ++++++++++++++++++ 5 files changed, 240 insertions(+) create mode 100644 drivers/virt/coco/arm-cca-guest/Kconfig create mode 100644 drivers/virt/coco/arm-cca-guest/Makefile create mode 100644 drivers/virt/coco/arm-cca-guest/arm-cca-guest.c diff --git a/drivers/virt/coco/Kconfig b/drivers/virt/coco/Kconfig index 2b2e2dd06c7f..dd1011c2e59e 100644 --- a/drivers/virt/coco/Kconfig +++ b/drivers/virt/coco/Kconfig @@ -14,3 +14,5 @@ source "drivers/virt/coco/sev-guest/Kconfig" source "drivers/virt/coco/tdx-guest/Kconfig" source "drivers/virt/coco/csv-guest/Kconfig" + +source "drivers/virt/coco/arm-cca-guest/Kconfig" diff --git a/drivers/virt/coco/Makefile b/drivers/virt/coco/Makefile index 8b289aaf73b0..a0c5840a3a33 100644 --- a/drivers/virt/coco/Makefile +++ b/drivers/virt/coco/Makefile @@ -7,3 +7,4 @@ obj-$(CONFIG_EFI_SECRET) += efi_secret/ obj-$(CONFIG_SEV_GUEST) += sev-guest/ obj-$(CONFIG_INTEL_TDX_GUEST) += tdx-guest/ obj-$(CONFIG_CSV_GUEST) += csv-guest/ +obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest/ diff --git a/drivers/virt/coco/arm-cca-guest/Kconfig b/drivers/virt/coco/arm-cca-guest/Kconfig new file mode 100644 index 000000000000..9dd27c3ee215 --- /dev/null +++ b/drivers/virt/coco/arm-cca-guest/Kconfig @@ -0,0 +1,11 @@ +config ARM_CCA_GUEST + tristate "Arm CCA Guest driver" + depends on ARM64 + default m + select TSM_REPORTS + help + The driver provides userspace interface to request and + attestation report from the Realm Management Monitor(RMM). + + If you choose 'M' here, this module will be called + arm-cca-guest. diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile new file mode 100644 index 000000000000..69eeba08e98a --- /dev/null +++ b/drivers/virt/coco/arm-cca-guest/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c b/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c new file mode 100644 index 000000000000..f937f6e1009e --- /dev/null +++ b/drivers/virt/coco/arm-cca-guest/arm-cca-guest.c @@ -0,0 +1,224 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023 ARM Ltd. + */ + +#include <linux/arm-smccc.h> +#include <linux/cc_platform.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/smp.h> +#include <linux/tsm.h> +#include <linux/types.h> + +#include <asm/rsi.h> + +/** + * struct arm_cca_token_info - a descriptor for the token buffer. + * @challenge: Pointer to the challenge data + * @challenge_size: Size of the challenge data + * @granule: PA of the granule to which the token will be written + * @offset: Offset within granule to start of buffer in bytes + * @result: result of rsi_attestation_token_continue operation + */ +struct arm_cca_token_info { + void *challenge; + unsigned long challenge_size; + phys_addr_t granule; + unsigned long offset; + unsigned long result; +}; + +static void arm_cca_attestation_init(void *param) +{ + struct arm_cca_token_info *info; + + info = (struct arm_cca_token_info *)param; + + info->result = rsi_attestation_token_init(info->challenge, + info->challenge_size); +} + +/** + * arm_cca_attestation_continue - Retrieve the attestation token data. + * + * @param: pointer to the arm_cca_token_info + * + * Attestation token generation is a long running operation and therefore + * the token data may not be retrieved in a single call. Moreover, the + * token retrieval operation must be requested on the same CPU on which the + * attestation token generation was initialised. + * This helper function is therefore scheduled on the same CPU multiple + * times until the entire token data is retrieved. + */ +static void arm_cca_attestation_continue(void *param) +{ + unsigned long len; + unsigned long size; + struct arm_cca_token_info *info; + + info = (struct arm_cca_token_info *)param; + + size = RSI_GRANULE_SIZE - info->offset; + info->result = rsi_attestation_token_continue(info->granule, + info->offset, size, &len); + info->offset += len; +} + +/** + * arm_cca_report_new - Generate a new attestation token. + * + * @report: pointer to the TSM report context information. + * @data: pointer to the context specific data for this module. + * + * Initialise the attestation token generation using the challenge data + * passed in the TSM descriptor. Allocate memory for the attestation token + * and schedule calls to retrieve the attestation token on the same CPU + * on which the attestation token generation was initialised. + * + * The challenge data must be at least 32 bytes and no more than 64 bytes. If + * less than 64 bytes are provided it will be zero padded to 64 bytes. + * + * Return: + * * %0 - Attestation token generated successfully. + * * %-EINVAL - A parameter was not valid. + * * %-ENOMEM - Out of memory. + * * %-EFAULT - Failed to get IPA for memory page(s). + * * A negative status code as returned by smp_call_function_single(). + */ +static int arm_cca_report_new(struct tsm_report *report, void *data) +{ + int ret; + int cpu; + long max_size; + unsigned long token_size = 0; + struct arm_cca_token_info info; + void *buf; + u8 *token __free(kvfree) = NULL; + struct tsm_desc *desc = &report->desc; + + if (desc->inblob_len < 32 || desc->inblob_len > 64) + return -EINVAL; + + /* + * The attestation token 'init' and 'continue' calls must be + * performed on the same CPU. smp_call_function_single() is used + * instead of simply calling get_cpu() because of the need to + * allocate outblob based on the returned value from the 'init' + * call and that cannot be done in an atomic context. + */ + cpu = smp_processor_id(); + + info.challenge = desc->inblob; + info.challenge_size = desc->inblob_len; + + ret = smp_call_function_single(cpu, arm_cca_attestation_init, + &info, true); + if (ret) + return ret; + max_size = info.result; + + if (max_size <= 0) + return -EINVAL; + + /* Allocate outblob */ + token = kvzalloc(max_size, GFP_KERNEL); + if (!token) + return -ENOMEM; + + /* + * Since the outblob may not be physically contiguous, use a page + * to bounce the buffer from RMM. + */ + buf = alloc_pages_exact(RSI_GRANULE_SIZE, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Get the PA of the memory page(s) that were allocated */ + info.granule = (unsigned long)virt_to_phys(buf); + + /* Loop until the token is ready or there is an error */ + do { + /* Retrieve one RSI_GRANULE_SIZE data per loop iteration */ + info.offset = 0; + do { + /* + * Schedule a call to retrieve a sub-granule chunk + * of data per loop iteration. + */ + ret = smp_call_function_single(cpu, + arm_cca_attestation_continue, + (void *)&info, true); + if (ret != 0) { + token_size = 0; + goto exit_free_granule_page; + } + } while (info.result == RSI_INCOMPLETE && + info.offset < RSI_GRANULE_SIZE); + + if (info.result != RSI_SUCCESS) { + ret = -ENXIO; + token_size = 0; + goto exit_free_granule_page; + } + + /* + * Copy the retrieved token data from the granule + * to the token buffer, ensuring that the RMM doesn't + * overflow the buffer. + */ + if (WARN_ON(token_size + info.offset > max_size)) + break; + memcpy(&token[token_size], buf, info.offset); + token_size += info.offset; + } while (info.result == RSI_INCOMPLETE); + + report->outblob = no_free_ptr(token); +exit_free_granule_page: + report->outblob_len = token_size; + free_pages_exact(buf, RSI_GRANULE_SIZE); + return ret; +} + +static const struct tsm_ops arm_cca_tsm_ops = { + .name = KBUILD_MODNAME, + .report_new = arm_cca_report_new, +}; + +/** + * arm_cca_guest_init - Register with the Trusted Security Module (TSM) + * interface. + * + * Return: + * * %0 - Registered successfully with the TSM interface. + * * %-ENODEV - The execution context is not an Arm Realm. + * * %-EBUSY - Already registered. + */ +static int __init arm_cca_guest_init(void) +{ + int ret; + + if (!is_realm_world()) + return -ENODEV; + + ret = tsm_register(&arm_cca_tsm_ops, NULL, NULL); + if (ret < 0) + pr_err("Error %d registering with TSM\n", ret); + + return ret; +} +module_init(arm_cca_guest_init); + +/** + * arm_cca_guest_exit - unregister with the Trusted Security Module (TSM) + * interface. + */ +static void __exit arm_cca_guest_exit(void) +{ + tsm_unregister(&arm_cca_tsm_ops); +} +module_exit(arm_cca_guest_exit); + +MODULE_AUTHOR("Sami Mujawar <sami.mujawar@arm.com>"); +MODULE_DESCRIPTION("Arm CCA Guest TSM Driver"); +MODULE_LICENSE("GPL"); -- 2.18.0.huawei.25