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Shutemov" , Andi Kleen , tony.luck@intel.com, marcorr@google.com, sathyanarayanan.kuppuswamy@linux.intel.com, Brijesh Singh Subject: [PATCH Part1 v5 36/38] virt: Add SEV-SNP guest driver Date: Fri, 20 Aug 2021 10:19:31 -0500 Message-Id: <20210820151933.22401-37-brijesh.singh@amd.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210820151933.22401-1-brijesh.singh@amd.com> References: <20210820151933.22401-1-brijesh.singh@amd.com> X-ClientProxiedBy: SA9P223CA0002.NAMP223.PROD.OUTLOOK.COM (2603:10b6:806:26::7) To SN6PR12MB2718.namprd12.prod.outlook.com (2603:10b6:805:6f::22) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from sbrijesh-desktop.amd.com (165.204.77.1) by SA9P223CA0002.NAMP223.PROD.OUTLOOK.COM (2603:10b6:806:26::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4436.19 via Frontend Transport; Fri, 20 Aug 2021 15:21:33 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 14ff181e-dc65-453f-c6a2-08d963ee3207 X-MS-TrafficTypeDiagnostic: SN6PR12MB2637: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:3044; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:SN6PR12MB2718.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(4636009)(366004)(396003)(136003)(346002)(376002)(39860400002)(36756003)(956004)(8936002)(2906002)(4326008)(52116002)(8676002)(83380400001)(2616005)(26005)(86362001)(7416002)(7406005)(186003)(66476007)(44832011)(38100700002)(54906003)(5660300002)(7696005)(38350700002)(1076003)(316002)(6486002)(66946007)(966005)(478600001)(30864003)(66556008);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 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 X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 14ff181e-dc65-453f-c6a2-08d963ee3207 X-MS-Exchange-CrossTenant-AuthSource: SN6PR12MB2718.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Aug 2021 15:21:34.4341 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: oPwe1Mv5kOz2DwhJ5SANuOEZdd9WSMz4NBqpgo7l7UWKXk4wLRa06EIFzXyZ5mOcs+fQc2Ge9Ewxr9zhi8kyDQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN6PR12MB2637 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org SEV-SNP specification provides the guest a mechanisum to communicate with the PSP without risk from a malicious hypervisor who wishes to read, alter, drop or replay the messages sent. The driver uses snp_issue_guest_request() to issue GHCB SNP_GUEST_REQUEST or SNP_EXT_GUEST_REQUEST NAE events to submit the request to PSP. The PSP requires that all communication should be encrypted using key specified through the platform_data. The userspace can use SNP_GET_REPORT ioctl() to query the guest attestation report. See SEV-SNP spec section Guest Messages for more details. Signed-off-by: Brijesh Singh --- Documentation/virt/coco/sevguest.rst | 69 ++++ drivers/virt/Kconfig | 3 + drivers/virt/Makefile | 1 + drivers/virt/coco/sevguest/Kconfig | 9 + drivers/virt/coco/sevguest/Makefile | 2 + drivers/virt/coco/sevguest/sevguest.c | 448 ++++++++++++++++++++++++++ drivers/virt/coco/sevguest/sevguest.h | 63 ++++ include/uapi/linux/sev-guest.h | 44 +++ 8 files changed, 639 insertions(+) create mode 100644 Documentation/virt/coco/sevguest.rst create mode 100644 drivers/virt/coco/sevguest/Kconfig create mode 100644 drivers/virt/coco/sevguest/Makefile create mode 100644 drivers/virt/coco/sevguest/sevguest.c create mode 100644 drivers/virt/coco/sevguest/sevguest.h create mode 100644 include/uapi/linux/sev-guest.h diff --git a/Documentation/virt/coco/sevguest.rst b/Documentation/virt/coco/sevguest.rst new file mode 100644 index 000000000000..52d5915037ef --- /dev/null +++ b/Documentation/virt/coco/sevguest.rst @@ -0,0 +1,69 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================================================== +The Definitive SEV Guest API Documentation +=================================================================== + +1. General description +====================== + +The SEV API is a set of ioctls that are issued to by the guest or +hypervisor to get or set certain aspect of the SEV virtual machine. +The ioctls belong to the following classes: + + - Hypervisor ioctls: These query and set global attributes which affect the + whole SEV firmware. These ioctl is used by platform provision tools. + + - Guest ioctls: These query and set attribute of the SEV virtual machine. + +2. API description +================== + +This section describes ioctls that can be used to query or set SEV guests. +For each ioctl, the following information is provided along with a +description: + + Technology: + which SEV techology provides this ioctl. sev, sev-es, sev-snp or all. + + Type: + hypervisor or guest. The ioctl can be used inside the guest or the + hypervisor. + + Parameters: + what parameters are accepted by the ioctl. + + Returns: + the return value. General error numbers (ENOMEM, EINVAL) + are not detailed, but errors with specific meanings are. + +The guest ioctl should be called to /dev/sev-guest device. The ioctl accepts +struct snp_user_guest_request. The input and output structure is specified +through the req_data and resp_data field respectively. If the ioctl fails +to execute due to the firmware error, then fw_err code will be set. + +:: + struct snp_user_guest_request { + /* Request and response structure address */ + __u64 req_data; + __u64 resp_data; + + /* firmware error code on failure (see psp-sev.h) */ + __u64 fw_err; + }; + +2.1 SNP_GET_REPORT +------------------ + +:Technology: sev-snp +:Type: guest ioctl +:Parameters (in): struct snp_report_req +:Returns (out): struct snp_report_resp on success, -negative on error + +The SNP_GET_REPORT ioctl can be used to query the attestation report from the +SEV-SNP firmware. The ioctl uses the SNP_GUEST_REQUEST (MSG_REPORT_REQ) command +provided by the SEV-SNP firmware to query the attestation report. + +On success, the snp_report_resp.data will contains the report. The report +format is described in the SEV-SNP specification. See the SEV-SNP specification +for further details. diff --git a/drivers/virt/Kconfig b/drivers/virt/Kconfig index 8061e8ef449f..e457e47610d3 100644 --- a/drivers/virt/Kconfig +++ b/drivers/virt/Kconfig @@ -36,4 +36,7 @@ source "drivers/virt/vboxguest/Kconfig" source "drivers/virt/nitro_enclaves/Kconfig" source "drivers/virt/acrn/Kconfig" + +source "drivers/virt/coco/sevguest/Kconfig" + endif diff --git a/drivers/virt/Makefile b/drivers/virt/Makefile index 3e272ea60cd9..9c704a6fdcda 100644 --- a/drivers/virt/Makefile +++ b/drivers/virt/Makefile @@ -8,3 +8,4 @@ obj-y += vboxguest/ obj-$(CONFIG_NITRO_ENCLAVES) += nitro_enclaves/ obj-$(CONFIG_ACRN_HSM) += acrn/ +obj-$(CONFIG_SEV_GUEST) += coco/sevguest/ diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig new file mode 100644 index 000000000000..96190919cca8 --- /dev/null +++ b/drivers/virt/coco/sevguest/Kconfig @@ -0,0 +1,9 @@ +config SEV_GUEST + tristate "AMD SEV Guest driver" + default y + depends on AMD_MEM_ENCRYPT && CRYPTO_AEAD2 + help + The driver can be used by the SEV-SNP guest to communicate with the PSP to + request the attestation report and more. + + If you choose 'M' here, this module will be called sevguest. diff --git a/drivers/virt/coco/sevguest/Makefile b/drivers/virt/coco/sevguest/Makefile new file mode 100644 index 000000000000..b1ffb2b4177b --- /dev/null +++ b/drivers/virt/coco/sevguest/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_SEV_GUEST) += sevguest.o diff --git a/drivers/virt/coco/sevguest/sevguest.c b/drivers/virt/coco/sevguest/sevguest.c new file mode 100644 index 000000000000..d029a98ad088 --- /dev/null +++ b/drivers/virt/coco/sevguest/sevguest.c @@ -0,0 +1,448 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AMD Secure Encrypted Virtualization Nested Paging (SEV-SNP) guest request interface + * + * Copyright (C) 2021 Advanced Micro Devices, Inc. + * + * Author: Brijesh Singh + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "sevguest.h" + +#define DEVICE_NAME "sev-guest" +#define AAD_LEN 48 +#define MSG_HDR_VER 1 + +struct snp_guest_crypto { + struct crypto_aead *tfm; + u8 *iv, *authtag; + int iv_len, a_len; +}; + +struct snp_guest_dev { + struct device *dev; + struct miscdevice misc; + + struct snp_guest_crypto *crypto; + struct snp_guest_msg *request, *response; +}; + +static u8 vmpck_id; +static DEFINE_MUTEX(snp_cmd_mutex); + +static inline struct snp_guest_dev *to_snp_dev(struct file *file) +{ + struct miscdevice *dev = file->private_data; + + return container_of(dev, struct snp_guest_dev, misc); +} + +static struct snp_guest_crypto *init_crypto(struct snp_guest_dev *snp_dev, u8 *key, size_t keylen) +{ + struct snp_guest_crypto *crypto; + + crypto = kzalloc(sizeof(*crypto), GFP_KERNEL_ACCOUNT); + if (!crypto) + return NULL; + + crypto->tfm = crypto_alloc_aead("gcm(aes)", 0, 0); + if (IS_ERR(crypto->tfm)) + goto e_free; + + if (crypto_aead_setkey(crypto->tfm, key, keylen)) + goto e_free_crypto; + + crypto->iv_len = crypto_aead_ivsize(crypto->tfm); + if (crypto->iv_len < 12) { + dev_err(snp_dev->dev, "IV length is less than 12.\n"); + goto e_free_crypto; + } + + crypto->iv = kmalloc(crypto->iv_len, GFP_KERNEL_ACCOUNT); + if (!crypto->iv) + goto e_free_crypto; + + if (crypto_aead_authsize(crypto->tfm) > MAX_AUTHTAG_LEN) { + if (crypto_aead_setauthsize(crypto->tfm, MAX_AUTHTAG_LEN)) { + dev_err(snp_dev->dev, "failed to set authsize to %d\n", MAX_AUTHTAG_LEN); + goto e_free_crypto; + } + } + + crypto->a_len = crypto_aead_authsize(crypto->tfm); + crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT); + if (!crypto->authtag) + goto e_free_crypto; + + return crypto; + +e_free_crypto: + crypto_free_aead(crypto->tfm); +e_free: + kfree(crypto->iv); + kfree(crypto->authtag); + kfree(crypto); + + return NULL; +} + +static void deinit_crypto(struct snp_guest_crypto *crypto) +{ + crypto_free_aead(crypto->tfm); + kfree(crypto->iv); + kfree(crypto->authtag); + kfree(crypto); +} + +static int enc_dec_message(struct snp_guest_crypto *crypto, struct snp_guest_msg *msg, + u8 *src_buf, u8 *dst_buf, size_t len, bool enc) +{ + struct snp_guest_msg_hdr *hdr = &msg->hdr; + struct scatterlist src[3], dst[3]; + DECLARE_CRYPTO_WAIT(wait); + struct aead_request *req; + int ret; + + req = aead_request_alloc(crypto->tfm, GFP_KERNEL); + if (!req) + return -ENOMEM; + + /* + * AEAD memory operations: + * +------ AAD -------+------- DATA -----+---- AUTHTAG----+ + * | msg header | plaintext | hdr->authtag | + * | bytes 30h - 5Fh | or | | + * | | cipher | | + * +------------------+------------------+----------------+ + */ + sg_init_table(src, 3); + sg_set_buf(&src[0], &hdr->algo, AAD_LEN); + sg_set_buf(&src[1], src_buf, hdr->msg_sz); + sg_set_buf(&src[2], hdr->authtag, crypto->a_len); + + sg_init_table(dst, 3); + sg_set_buf(&dst[0], &hdr->algo, AAD_LEN); + sg_set_buf(&dst[1], dst_buf, hdr->msg_sz); + sg_set_buf(&dst[2], hdr->authtag, crypto->a_len); + + aead_request_set_ad(req, AAD_LEN); + aead_request_set_tfm(req, crypto->tfm); + aead_request_set_callback(req, 0, crypto_req_done, &wait); + + aead_request_set_crypt(req, src, dst, len, crypto->iv); + ret = crypto_wait_req(enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req), &wait); + + aead_request_free(req); + return ret; +} + +static int __enc_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg, + void *plaintext, size_t len) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_guest_msg_hdr *hdr = &msg->hdr; + + memset(crypto->iv, 0, crypto->iv_len); + memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno)); + + return enc_dec_message(crypto, msg, plaintext, msg->payload, len, true); +} + +static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg, + void *plaintext, size_t len) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_guest_msg_hdr *hdr = &msg->hdr; + + /* Build IV with response buffer sequence number */ + memset(crypto->iv, 0, crypto->iv_len); + memcpy(crypto->iv, &hdr->msg_seqno, sizeof(hdr->msg_seqno)); + + return enc_dec_message(crypto, msg, msg->payload, plaintext, len, false); +} + +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_guest_msg *resp = snp_dev->response; + struct snp_guest_msg *req = snp_dev->request; + struct snp_guest_msg_hdr *req_hdr = &req->hdr; + struct snp_guest_msg_hdr *resp_hdr = &resp->hdr; + + dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n", + resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz); + + /* Verify that the sequence counter is incremented by 1 */ + if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1))) + return -EBADMSG; + + /* Verify response message type and version number. */ + if (resp_hdr->msg_type != (req_hdr->msg_type + 1) || + resp_hdr->msg_version != req_hdr->msg_version) + return -EBADMSG; + + /* + * If the message size is greater than our buffer length then return + * an error. + */ + if (unlikely((resp_hdr->msg_sz + crypto->a_len) > sz)) + return -EBADMSG; + + return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len); +} + +static bool enc_payload(struct snp_guest_dev *snp_dev, int version, u8 type, + void *payload, size_t sz) +{ + struct snp_guest_msg *req = snp_dev->request; + struct snp_guest_msg_hdr *hdr = &req->hdr; + + memset(req, 0, sizeof(*req)); + + hdr->algo = SNP_AEAD_AES_256_GCM; + hdr->hdr_version = MSG_HDR_VER; + hdr->hdr_sz = sizeof(*hdr); + hdr->msg_type = type; + hdr->msg_version = version; + hdr->msg_seqno = snp_msg_seqno(); + hdr->msg_vmpck = vmpck_id; + hdr->msg_sz = sz; + + dev_dbg(snp_dev->dev, "request [seqno %lld type %d version %d sz %d]\n", + hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz); + + return __enc_payload(snp_dev, req, payload, sz); +} + +static int handle_guest_request(struct snp_guest_dev *snp_dev, int version, u8 type, + void *req_buf, size_t req_sz, void *resp_buf, + u32 resp_sz, __u64 *fw_err) +{ + struct snp_guest_request_data data; + unsigned long err; + int rc; + + memset(snp_dev->response, 0, sizeof(*snp_dev->response)); + + /* Encrypt the userspace provided payload */ + rc = enc_payload(snp_dev, version, type, req_buf, req_sz); + if (rc) + return rc; + + /* Call firmware to process the request */ + data.req_gpa = __pa(snp_dev->request); + data.resp_gpa = __pa(snp_dev->response); + rc = snp_issue_guest_request(GUEST_REQUEST, &data, &err); + + if (fw_err) + *fw_err = err; + + if (rc) + return rc; + + return verify_and_dec_payload(snp_dev, resp_buf, resp_sz); +} + +static int get_report(struct snp_guest_dev *snp_dev, struct snp_user_guest_request *arg) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_report_resp *resp; + struct snp_report_req req; + int rc, resp_len; + + if (!arg->req_data || !arg->resp_data) + return -EINVAL; + + /* Copy the request payload from the userspace */ + if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + return -EFAULT; + + /* Message version must be non-zero */ + if (!req.msg_version) + return -EINVAL; + + /* + * The intermediate response buffer is used while decrypting the + * response payload. Make sure that it has enough space to cover the + * authtag. + */ + resp_len = sizeof(resp->data) + crypto->a_len; + resp = kzalloc(resp_len, GFP_KERNEL_ACCOUNT); + if (!resp) + return -ENOMEM; + + /* Issue the command to get the attestation report */ + rc = handle_guest_request(snp_dev, req.msg_version, SNP_MSG_REPORT_REQ, + &req.user_data, sizeof(req.user_data), resp->data, resp_len, + &arg->fw_err); + if (rc) + goto e_free; + + /* Copy the response payload to userspace */ + if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) + rc = -EFAULT; + +e_free: + kfree(resp); + return rc; +} + +static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long arg) +{ + struct snp_guest_dev *snp_dev = to_snp_dev(file); + void __user *argp = (void __user *)arg; + struct snp_user_guest_request input; + int ret = -ENOTTY; + + if (copy_from_user(&input, argp, sizeof(input))) + return -EFAULT; + + mutex_lock(&snp_cmd_mutex); + + switch (ioctl) { + case SNP_GET_REPORT: { + ret = get_report(snp_dev, &input); + break; + } + default: + break; + } + + mutex_unlock(&snp_cmd_mutex); + + if (copy_to_user(argp, &input, sizeof(input))) + return -EFAULT; + + return ret; +} + +static void free_shared_pages(void *buf, size_t sz) +{ + unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; + + /* If fail to restore the encryption mask then leak it. */ + if (set_memory_encrypted((unsigned long)buf, npages)) + return; + + __free_pages(virt_to_page(buf), get_order(sz)); +} + +static void *alloc_shared_pages(size_t sz) +{ + unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; + struct page *page; + int ret; + + page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz)); + if (IS_ERR(page)) + return NULL; + + ret = set_memory_decrypted((unsigned long)page_address(page), npages); + if (ret) { + __free_pages(page, get_order(sz)); + return NULL; + } + + return page_address(page); +} + +static const struct file_operations snp_guest_fops = { + .owner = THIS_MODULE, + .unlocked_ioctl = snp_guest_ioctl, +}; + +static int __init snp_guest_probe(struct platform_device *pdev) +{ + struct snp_guest_platform_data *data; + struct device *dev = &pdev->dev; + struct snp_guest_dev *snp_dev; + struct miscdevice *misc; + int ret; + + if (!dev->platform_data) + return -ENODEV; + + data = (struct snp_guest_platform_data *)dev->platform_data; + vmpck_id = data->vmpck_id; + + snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL); + if (!snp_dev) + return -ENOMEM; + + platform_set_drvdata(pdev, snp_dev); + snp_dev->dev = dev; + + snp_dev->crypto = init_crypto(snp_dev, data->vmpck, sizeof(data->vmpck)); + if (!snp_dev->crypto) + return -EIO; + + /* Allocate the shared page used for the request and response message. */ + snp_dev->request = alloc_shared_pages(sizeof(struct snp_guest_msg)); + if (IS_ERR(snp_dev->request)) { + ret = PTR_ERR(snp_dev->request); + goto e_free_crypto; + } + + snp_dev->response = alloc_shared_pages(sizeof(struct snp_guest_msg)); + if (IS_ERR(snp_dev->response)) { + ret = PTR_ERR(snp_dev->response); + goto e_free_req; + } + + misc = &snp_dev->misc; + misc->minor = MISC_DYNAMIC_MINOR; + misc->name = DEVICE_NAME; + misc->fops = &snp_guest_fops; + + return misc_register(misc); + +e_free_req: + free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); + +e_free_crypto: + deinit_crypto(snp_dev->crypto); + + return ret; +} + +static int __exit snp_guest_remove(struct platform_device *pdev) +{ + struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev); + + free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); + free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg)); + deinit_crypto(snp_dev->crypto); + misc_deregister(&snp_dev->misc); + + return 0; +} + +static struct platform_driver snp_guest_driver = { + .remove = __exit_p(snp_guest_remove), + .driver = { + .name = "snp-guest", + }, +}; + +module_platform_driver_probe(snp_guest_driver, snp_guest_probe); + +MODULE_AUTHOR("Brijesh Singh "); +MODULE_LICENSE("GPL"); +MODULE_VERSION("1.0.0"); +MODULE_DESCRIPTION("AMD SNP Guest Driver"); diff --git a/drivers/virt/coco/sevguest/sevguest.h b/drivers/virt/coco/sevguest/sevguest.h new file mode 100644 index 000000000000..4cd2f8b81154 --- /dev/null +++ b/drivers/virt/coco/sevguest/sevguest.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2021 Advanced Micro Devices, Inc. + * + * Author: Brijesh Singh + * + * SEV-SNP API spec is available at https://developer.amd.com/sev + */ + +#ifndef __LINUX_SEVGUEST_H_ +#define __LINUX_SEVGUEST_H_ + +#include + +#define MAX_AUTHTAG_LEN 32 + +/* See SNP spec SNP_GUEST_REQUEST section for the structure */ +enum msg_type { + SNP_MSG_TYPE_INVALID = 0, + SNP_MSG_CPUID_REQ, + SNP_MSG_CPUID_RSP, + SNP_MSG_KEY_REQ, + SNP_MSG_KEY_RSP, + SNP_MSG_REPORT_REQ, + SNP_MSG_REPORT_RSP, + SNP_MSG_EXPORT_REQ, + SNP_MSG_EXPORT_RSP, + SNP_MSG_IMPORT_REQ, + SNP_MSG_IMPORT_RSP, + SNP_MSG_ABSORB_REQ, + SNP_MSG_ABSORB_RSP, + SNP_MSG_VMRK_REQ, + SNP_MSG_VMRK_RSP, + + SNP_MSG_TYPE_MAX +}; + +enum aead_algo { + SNP_AEAD_INVALID, + SNP_AEAD_AES_256_GCM, +}; + +struct snp_guest_msg_hdr { + u8 authtag[MAX_AUTHTAG_LEN]; + u64 msg_seqno; + u8 rsvd1[8]; + u8 algo; + u8 hdr_version; + u16 hdr_sz; + u8 msg_type; + u8 msg_version; + u16 msg_sz; + u32 rsvd2; + u8 msg_vmpck; + u8 rsvd3[35]; +} __packed; + +struct snp_guest_msg { + struct snp_guest_msg_hdr hdr; + u8 payload[4000]; +} __packed; + +#endif /* __LINUX_SNP_GUEST_H__ */ diff --git a/include/uapi/linux/sev-guest.h b/include/uapi/linux/sev-guest.h new file mode 100644 index 000000000000..e8cfd15133f3 --- /dev/null +++ b/include/uapi/linux/sev-guest.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */ +/* + * Userspace interface for AMD SEV and SEV-SNP guest driver. + * + * Copyright (C) 2021 Advanced Micro Devices, Inc. + * + * Author: Brijesh Singh + * + * SEV API specification is available at: https://developer.amd.com/sev/ + */ + +#ifndef __UAPI_LINUX_SEV_GUEST_H_ +#define __UAPI_LINUX_SEV_GUEST_H_ + +#include + +struct snp_report_req { + /* message version number (must be non-zero) */ + __u8 msg_version; + + /* user data that should be included in the report */ + __u8 user_data[64]; +}; + +struct snp_report_resp { + /* response data, see SEV-SNP spec for the format */ + __u8 data[4000]; +}; + +struct snp_user_guest_request { + /* Request and response structure address */ + __u64 req_data; + __u64 resp_data; + + /* firmware error code on failure (see psp-sev.h) */ + __u64 fw_err; +}; + +#define SNP_GUEST_REQ_IOC_TYPE 'S' + +/* Get SNP attestation report */ +#define SNP_GET_REPORT _IOWR(SNP_GUEST_REQ_IOC_TYPE, 0x0, struct snp_user_guest_request) + +#endif /* __UAPI_LINUX_SEV_GUEST_H_ */