From d63670d23e60f00210635ca7c62bce27bec55f1b Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Wed, 20 Apr 2022 09:14:14 -0500 Subject: virt: sevguest: Rename the sevguest dir and files to sev-guest Rename the drivers/virt/coco/sevguest directory and files to sev-guest so as to match the driver name. [ bp: Rename Documentation/virt/coco/sevguest.rst too, as reported by sfr: https://lore.kernel.org/r/20220427101059.3bf55262@canb.auug.org.au ] Signed-off-by: Tom Lendacky Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/2f5c9cb16e3a67599c8e3170f6c72c8712c47d53.1650464054.git.thomas.lendacky@amd.com --- drivers/virt/coco/sev-guest/Kconfig | 14 + drivers/virt/coco/sev-guest/Makefile | 2 + drivers/virt/coco/sev-guest/sev-guest.c | 743 ++++++++++++++++++++++++++++++++ drivers/virt/coco/sev-guest/sev-guest.h | 98 +++++ drivers/virt/coco/sevguest/Kconfig | 14 - drivers/virt/coco/sevguest/Makefile | 2 - drivers/virt/coco/sevguest/sevguest.c | 743 -------------------------------- drivers/virt/coco/sevguest/sevguest.h | 98 ----- 8 files changed, 857 insertions(+), 857 deletions(-) create mode 100644 drivers/virt/coco/sev-guest/Kconfig create mode 100644 drivers/virt/coco/sev-guest/Makefile create mode 100644 drivers/virt/coco/sev-guest/sev-guest.c create mode 100644 drivers/virt/coco/sev-guest/sev-guest.h delete mode 100644 drivers/virt/coco/sevguest/Kconfig delete mode 100644 drivers/virt/coco/sevguest/Makefile delete mode 100644 drivers/virt/coco/sevguest/sevguest.c delete mode 100644 drivers/virt/coco/sevguest/sevguest.h (limited to 'drivers/virt/coco') diff --git a/drivers/virt/coco/sev-guest/Kconfig b/drivers/virt/coco/sev-guest/Kconfig new file mode 100644 index 000000000000..f9db0799ae67 --- /dev/null +++ b/drivers/virt/coco/sev-guest/Kconfig @@ -0,0 +1,14 @@ +config SEV_GUEST + tristate "AMD SEV Guest driver" + default m + depends on AMD_MEM_ENCRYPT + select CRYPTO_AEAD2 + select CRYPTO_GCM + help + SEV-SNP firmware provides the guest a mechanism to communicate with + the PSP without risk from a malicious hypervisor who wishes to read, + alter, drop or replay the messages sent. The driver provides + userspace interface to communicate with the PSP to request the + attestation report and more. + + If you choose 'M' here, this module will be called sev-guest. diff --git a/drivers/virt/coco/sev-guest/Makefile b/drivers/virt/coco/sev-guest/Makefile new file mode 100644 index 000000000000..63d67c27723a --- /dev/null +++ b/drivers/virt/coco/sev-guest/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_SEV_GUEST) += sev-guest.o diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c new file mode 100644 index 000000000000..90ce16b6e05f --- /dev/null +++ b/drivers/virt/coco/sev-guest/sev-guest.c @@ -0,0 +1,743 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * AMD Secure Encrypted Virtualization (SEV) guest driver 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 + +#include "sev-guest.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; + + void *certs_data; + struct snp_guest_crypto *crypto; + struct snp_guest_msg *request, *response; + struct snp_secrets_page_layout *layout; + struct snp_req_data input; + u32 *os_area_msg_seqno; + u8 *vmpck; +}; + +static u32 vmpck_id; +module_param(vmpck_id, uint, 0444); +MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP."); + +/* Mutex to serialize the shared buffer access and command handling. */ +static DEFINE_MUTEX(snp_cmd_mutex); + +static bool is_vmpck_empty(struct snp_guest_dev *snp_dev) +{ + char zero_key[VMPCK_KEY_LEN] = {0}; + + if (snp_dev->vmpck) + return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN); + + return true; +} + +static void snp_disable_vmpck(struct snp_guest_dev *snp_dev) +{ + memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN); + snp_dev->vmpck = NULL; +} + +static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev) +{ + u64 count; + + lockdep_assert_held(&snp_cmd_mutex); + + /* Read the current message sequence counter from secrets pages */ + count = *snp_dev->os_area_msg_seqno; + + return count + 1; +} + +/* Return a non-zero on success */ +static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev) +{ + u64 count = __snp_get_msg_seqno(snp_dev); + + /* + * The message sequence counter for the SNP guest request is a 64-bit + * value but the version 2 of GHCB specification defines a 32-bit storage + * for it. If the counter exceeds the 32-bit value then return zero. + * The caller should check the return value, but if the caller happens to + * not check the value and use it, then the firmware treats zero as an + * invalid number and will fail the message request. + */ + if (count >= UINT_MAX) { + dev_err(snp_dev->dev, "request message sequence counter overflow\n"); + return 0; + } + + return count; +} + +static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev) +{ + /* + * The counter is also incremented by the PSP, so increment it by 2 + * and save in secrets page. + */ + *snp_dev->os_area_msg_seqno += 2; +} + +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); + 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_iv; + } + } + + crypto->a_len = crypto_aead_authsize(crypto->tfm); + crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT); + if (!crypto->authtag) + goto e_free_auth; + + return crypto; + +e_free_auth: + kfree(crypto->authtag); +e_free_iv: + kfree(crypto->iv); +e_free_crypto: + crypto_free_aead(crypto->tfm); +e_free: + 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; + + /* Decrypt the payload */ + return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len); +} + +static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, 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 = seqno; + hdr->msg_vmpck = vmpck_id; + hdr->msg_sz = sz; + + /* Verify the sequence number is non-zero */ + if (!hdr->msg_seqno) + return -ENOSR; + + 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, u64 exit_code, int msg_ver, + u8 type, void *req_buf, size_t req_sz, void *resp_buf, + u32 resp_sz, __u64 *fw_err) +{ + unsigned long err; + u64 seqno; + int rc; + + /* Get message sequence and verify that its a non-zero */ + seqno = snp_get_msg_seqno(snp_dev); + if (!seqno) + return -EIO; + + memset(snp_dev->response, 0, sizeof(struct snp_guest_msg)); + + /* Encrypt the userspace provided payload */ + rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz); + if (rc) + return rc; + + /* Call firmware to process the request */ + rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); + if (fw_err) + *fw_err = err; + + if (rc) + return rc; + + /* + * The verify_and_dec_payload() will fail only if the hypervisor is + * actively modifying the message header or corrupting the encrypted payload. + * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that + * the key cannot be used for any communication. The key is disabled to ensure + * that AES-GCM does not use the same IV while encrypting the request payload. + */ + rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz); + if (rc) { + dev_alert(snp_dev->dev, + "Detected unexpected decode failure, disabling the vmpck_id %d\n", + vmpck_id); + snp_disable_vmpck(snp_dev); + return rc; + } + + /* Increment to new message sequence after payload decryption was successful. */ + snp_inc_msg_seqno(snp_dev); + + return 0; +} + +static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_report_resp *resp; + struct snp_report_req req; + int rc, resp_len; + + lockdep_assert_held(&snp_cmd_mutex); + + if (!arg->req_data || !arg->resp_data) + return -EINVAL; + + if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + return -EFAULT; + + /* + * 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; + + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, + SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data, + resp_len, &arg->fw_err); + if (rc) + goto e_free; + + if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) + rc = -EFAULT; + +e_free: + kfree(resp); + return rc; +} + +static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_derived_key_resp resp = {0}; + struct snp_derived_key_req req; + int rc, resp_len; + /* Response data is 64 bytes and max authsize for GCM is 16 bytes. */ + u8 buf[64 + 16]; + + lockdep_assert_held(&snp_cmd_mutex); + + if (!arg->req_data || !arg->resp_data) + 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; + if (sizeof(buf) < resp_len) + return -ENOMEM; + + if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + return -EFAULT; + + rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, + SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len, + &arg->fw_err); + if (rc) + return rc; + + memcpy(resp.data, buf, sizeof(resp.data)); + if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp))) + rc = -EFAULT; + + /* The response buffer contains the sensitive data, explicitly clear it. */ + memzero_explicit(buf, sizeof(buf)); + memzero_explicit(&resp, sizeof(resp)); + return rc; +} + +static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) +{ + struct snp_guest_crypto *crypto = snp_dev->crypto; + struct snp_ext_report_req req; + struct snp_report_resp *resp; + int ret, npages = 0, resp_len; + + lockdep_assert_held(&snp_cmd_mutex); + + if (!arg->req_data || !arg->resp_data) + return -EINVAL; + + if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) + return -EFAULT; + + /* userspace does not want certificate data */ + if (!req.certs_len || !req.certs_address) + goto cmd; + + if (req.certs_len > SEV_FW_BLOB_MAX_SIZE || + !IS_ALIGNED(req.certs_len, PAGE_SIZE)) + return -EINVAL; + + if (!access_ok((const void __user *)req.certs_address, req.certs_len)) + return -EFAULT; + + /* + * Initialize the intermediate buffer with all zeros. This buffer + * is used in the guest request message to get the certs blob from + * the host. If host does not supply any certs in it, then copy + * zeros to indicate that certificate data was not provided. + */ + memset(snp_dev->certs_data, 0, req.certs_len); + npages = req.certs_len >> PAGE_SHIFT; +cmd: + /* + * 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; + + snp_dev->input.data_npages = npages; + ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version, + SNP_MSG_REPORT_REQ, &req.data, + sizeof(req.data), resp->data, resp_len, &arg->fw_err); + + /* If certs length is invalid then copy the returned length */ + if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) { + req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT; + + if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req))) + ret = -EFAULT; + } + + if (ret) + goto e_free; + + if (npages && + copy_to_user((void __user *)req.certs_address, snp_dev->certs_data, + req.certs_len)) { + ret = -EFAULT; + goto e_free; + } + + if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) + ret = -EFAULT; + +e_free: + kfree(resp); + return ret; +} + +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_guest_request_ioctl input; + int ret = -ENOTTY; + + if (copy_from_user(&input, argp, sizeof(input))) + return -EFAULT; + + input.fw_err = 0xff; + + /* Message version must be non-zero */ + if (!input.msg_version) + return -EINVAL; + + mutex_lock(&snp_cmd_mutex); + + /* Check if the VMPCK is not empty */ + if (is_vmpck_empty(snp_dev)) { + dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n"); + mutex_unlock(&snp_cmd_mutex); + return -ENOTTY; + } + + switch (ioctl) { + case SNP_GET_REPORT: + ret = get_report(snp_dev, &input); + break; + case SNP_GET_DERIVED_KEY: + ret = get_derived_key(snp_dev, &input); + break; + case SNP_GET_EXT_REPORT: + ret = get_ext_report(snp_dev, &input); + break; + default: + break; + } + + mutex_unlock(&snp_cmd_mutex); + + if (input.fw_err && 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; + int ret; + + if (!buf) + return; + + ret = set_memory_encrypted((unsigned long)buf, npages); + if (ret) { + WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n"); + return; + } + + __free_pages(virt_to_page(buf), get_order(sz)); +} + +static void *alloc_shared_pages(struct device *dev, 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 (!page) + return NULL; + + ret = set_memory_decrypted((unsigned long)page_address(page), npages); + if (ret) { + dev_err(dev, "failed to mark page shared, ret=%d\n", 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 u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno) +{ + u8 *key = NULL; + + switch (id) { + case 0: + *seqno = &layout->os_area.msg_seqno_0; + key = layout->vmpck0; + break; + case 1: + *seqno = &layout->os_area.msg_seqno_1; + key = layout->vmpck1; + break; + case 2: + *seqno = &layout->os_area.msg_seqno_2; + key = layout->vmpck2; + break; + case 3: + *seqno = &layout->os_area.msg_seqno_3; + key = layout->vmpck3; + break; + default: + break; + } + + return key; +} + +static int __init sev_guest_probe(struct platform_device *pdev) +{ + struct snp_secrets_page_layout *layout; + struct sev_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 sev_guest_platform_data *)dev->platform_data; + layout = (__force void *)ioremap_encrypted(data->secrets_gpa, PAGE_SIZE); + if (!layout) + return -ENODEV; + + ret = -ENOMEM; + snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL); + if (!snp_dev) + goto e_unmap; + + ret = -EINVAL; + snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno); + if (!snp_dev->vmpck) { + dev_err(dev, "invalid vmpck id %d\n", vmpck_id); + goto e_unmap; + } + + /* Verify that VMPCK is not zero. */ + if (is_vmpck_empty(snp_dev)) { + dev_err(dev, "vmpck id %d is null\n", vmpck_id); + goto e_unmap; + } + + platform_set_drvdata(pdev, snp_dev); + snp_dev->dev = dev; + snp_dev->layout = layout; + + /* Allocate the shared page used for the request and response message. */ + snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg)); + if (!snp_dev->request) + goto e_unmap; + + snp_dev->response = alloc_shared_pages(dev, sizeof(struct snp_guest_msg)); + if (!snp_dev->response) + goto e_free_request; + + snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE); + if (!snp_dev->certs_data) + goto e_free_response; + + ret = -EIO; + snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN); + if (!snp_dev->crypto) + goto e_free_cert_data; + + misc = &snp_dev->misc; + misc->minor = MISC_DYNAMIC_MINOR; + misc->name = DEVICE_NAME; + misc->fops = &snp_guest_fops; + + /* initial the input address for guest request */ + snp_dev->input.req_gpa = __pa(snp_dev->request); + snp_dev->input.resp_gpa = __pa(snp_dev->response); + snp_dev->input.data_gpa = __pa(snp_dev->certs_data); + + ret = misc_register(misc); + if (ret) + goto e_free_cert_data; + + dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id); + return 0; + +e_free_cert_data: + free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE); +e_free_response: + free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg)); +e_free_request: + free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); +e_unmap: + iounmap(layout); + return ret; +} + +static int __exit sev_guest_remove(struct platform_device *pdev) +{ + struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev); + + free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE); + free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg)); + free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); + deinit_crypto(snp_dev->crypto); + misc_deregister(&snp_dev->misc); + + return 0; +} + +/* + * This driver is meant to be a common SEV guest interface driver and to + * support any SEV guest API. As such, even though it has been introduced + * with the SEV-SNP support, it is named "sev-guest". + */ +static struct platform_driver sev_guest_driver = { + .remove = __exit_p(sev_guest_remove), + .driver = { + .name = "sev-guest", + }, +}; + +module_platform_driver_probe(sev_guest_driver, sev_guest_probe); + +MODULE_AUTHOR("Brijesh Singh "); +MODULE_LICENSE("GPL"); +MODULE_VERSION("1.0.0"); +MODULE_DESCRIPTION("AMD SEV Guest Driver"); diff --git a/drivers/virt/coco/sev-guest/sev-guest.h b/drivers/virt/coco/sev-guest/sev-guest.h new file mode 100644 index 000000000000..d39bdd013765 --- /dev/null +++ b/drivers/virt/coco/sev-guest/sev-guest.h @@ -0,0 +1,98 @@ +/* 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 __VIRT_SEVGUEST_H__ +#define __VIRT_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; + +/* + * The secrets page contains 96-bytes of reserved field that can be used by + * the guest OS. The guest OS uses the area to save the message sequence + * number for each VMPCK. + * + * See the GHCB spec section Secret page layout for the format for this area. + */ +struct secrets_os_area { + u32 msg_seqno_0; + u32 msg_seqno_1; + u32 msg_seqno_2; + u32 msg_seqno_3; + u64 ap_jump_table_pa; + u8 rsvd[40]; + u8 guest_usage[32]; +} __packed; + +#define VMPCK_KEY_LEN 32 + +/* See the SNP spec version 0.9 for secrets page format */ +struct snp_secrets_page_layout { + u32 version; + u32 imien : 1, + rsvd1 : 31; + u32 fms; + u32 rsvd2; + u8 gosvw[16]; + u8 vmpck0[VMPCK_KEY_LEN]; + u8 vmpck1[VMPCK_KEY_LEN]; + u8 vmpck2[VMPCK_KEY_LEN]; + u8 vmpck3[VMPCK_KEY_LEN]; + struct secrets_os_area os_area; + u8 rsvd3[3840]; +} __packed; + +#endif /* __VIRT_SEVGUEST_H__ */ diff --git a/drivers/virt/coco/sevguest/Kconfig b/drivers/virt/coco/sevguest/Kconfig deleted file mode 100644 index 74ca1fe09437..000000000000 --- a/drivers/virt/coco/sevguest/Kconfig +++ /dev/null @@ -1,14 +0,0 @@ -config SEV_GUEST - tristate "AMD SEV Guest driver" - default m - depends on AMD_MEM_ENCRYPT - select CRYPTO_AEAD2 - select CRYPTO_GCM - help - SEV-SNP firmware provides the guest a mechanism to communicate with - the PSP without risk from a malicious hypervisor who wishes to read, - alter, drop or replay the messages sent. The driver provides - userspace interface 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 deleted file mode 100644 index b1ffb2b4177b..000000000000 --- a/drivers/virt/coco/sevguest/Makefile +++ /dev/null @@ -1,2 +0,0 @@ -# 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 deleted file mode 100644 index 18c3231a816d..000000000000 --- a/drivers/virt/coco/sevguest/sevguest.c +++ /dev/null @@ -1,743 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * AMD Secure Encrypted Virtualization (SEV) guest driver 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 - -#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; - - void *certs_data; - struct snp_guest_crypto *crypto; - struct snp_guest_msg *request, *response; - struct snp_secrets_page_layout *layout; - struct snp_req_data input; - u32 *os_area_msg_seqno; - u8 *vmpck; -}; - -static u32 vmpck_id; -module_param(vmpck_id, uint, 0444); -MODULE_PARM_DESC(vmpck_id, "The VMPCK ID to use when communicating with the PSP."); - -/* Mutex to serialize the shared buffer access and command handling. */ -static DEFINE_MUTEX(snp_cmd_mutex); - -static bool is_vmpck_empty(struct snp_guest_dev *snp_dev) -{ - char zero_key[VMPCK_KEY_LEN] = {0}; - - if (snp_dev->vmpck) - return !memcmp(snp_dev->vmpck, zero_key, VMPCK_KEY_LEN); - - return true; -} - -static void snp_disable_vmpck(struct snp_guest_dev *snp_dev) -{ - memzero_explicit(snp_dev->vmpck, VMPCK_KEY_LEN); - snp_dev->vmpck = NULL; -} - -static inline u64 __snp_get_msg_seqno(struct snp_guest_dev *snp_dev) -{ - u64 count; - - lockdep_assert_held(&snp_cmd_mutex); - - /* Read the current message sequence counter from secrets pages */ - count = *snp_dev->os_area_msg_seqno; - - return count + 1; -} - -/* Return a non-zero on success */ -static u64 snp_get_msg_seqno(struct snp_guest_dev *snp_dev) -{ - u64 count = __snp_get_msg_seqno(snp_dev); - - /* - * The message sequence counter for the SNP guest request is a 64-bit - * value but the version 2 of GHCB specification defines a 32-bit storage - * for it. If the counter exceeds the 32-bit value then return zero. - * The caller should check the return value, but if the caller happens to - * not check the value and use it, then the firmware treats zero as an - * invalid number and will fail the message request. - */ - if (count >= UINT_MAX) { - dev_err(snp_dev->dev, "request message sequence counter overflow\n"); - return 0; - } - - return count; -} - -static void snp_inc_msg_seqno(struct snp_guest_dev *snp_dev) -{ - /* - * The counter is also incremented by the PSP, so increment it by 2 - * and save in secrets page. - */ - *snp_dev->os_area_msg_seqno += 2; -} - -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); - 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_iv; - } - } - - crypto->a_len = crypto_aead_authsize(crypto->tfm); - crypto->authtag = kmalloc(crypto->a_len, GFP_KERNEL_ACCOUNT); - if (!crypto->authtag) - goto e_free_auth; - - return crypto; - -e_free_auth: - kfree(crypto->authtag); -e_free_iv: - kfree(crypto->iv); -e_free_crypto: - crypto_free_aead(crypto->tfm); -e_free: - 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; - - /* Decrypt the payload */ - return dec_payload(snp_dev, resp, payload, resp_hdr->msg_sz + crypto->a_len); -} - -static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, 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 = seqno; - hdr->msg_vmpck = vmpck_id; - hdr->msg_sz = sz; - - /* Verify the sequence number is non-zero */ - if (!hdr->msg_seqno) - return -ENOSR; - - 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, u64 exit_code, int msg_ver, - u8 type, void *req_buf, size_t req_sz, void *resp_buf, - u32 resp_sz, __u64 *fw_err) -{ - unsigned long err; - u64 seqno; - int rc; - - /* Get message sequence and verify that its a non-zero */ - seqno = snp_get_msg_seqno(snp_dev); - if (!seqno) - return -EIO; - - memset(snp_dev->response, 0, sizeof(struct snp_guest_msg)); - - /* Encrypt the userspace provided payload */ - rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz); - if (rc) - return rc; - - /* Call firmware to process the request */ - rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err); - if (fw_err) - *fw_err = err; - - if (rc) - return rc; - - /* - * The verify_and_dec_payload() will fail only if the hypervisor is - * actively modifying the message header or corrupting the encrypted payload. - * This hints that hypervisor is acting in a bad faith. Disable the VMPCK so that - * the key cannot be used for any communication. The key is disabled to ensure - * that AES-GCM does not use the same IV while encrypting the request payload. - */ - rc = verify_and_dec_payload(snp_dev, resp_buf, resp_sz); - if (rc) { - dev_alert(snp_dev->dev, - "Detected unexpected decode failure, disabling the vmpck_id %d\n", - vmpck_id); - snp_disable_vmpck(snp_dev); - return rc; - } - - /* Increment to new message sequence after payload decryption was successful. */ - snp_inc_msg_seqno(snp_dev); - - return 0; -} - -static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) -{ - struct snp_guest_crypto *crypto = snp_dev->crypto; - struct snp_report_resp *resp; - struct snp_report_req req; - int rc, resp_len; - - lockdep_assert_held(&snp_cmd_mutex); - - if (!arg->req_data || !arg->resp_data) - return -EINVAL; - - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) - return -EFAULT; - - /* - * 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; - - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, - SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data, - resp_len, &arg->fw_err); - if (rc) - goto e_free; - - if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) - rc = -EFAULT; - -e_free: - kfree(resp); - return rc; -} - -static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) -{ - struct snp_guest_crypto *crypto = snp_dev->crypto; - struct snp_derived_key_resp resp = {0}; - struct snp_derived_key_req req; - int rc, resp_len; - /* Response data is 64 bytes and max authsize for GCM is 16 bytes. */ - u8 buf[64 + 16]; - - lockdep_assert_held(&snp_cmd_mutex); - - if (!arg->req_data || !arg->resp_data) - 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; - if (sizeof(buf) < resp_len) - return -ENOMEM; - - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) - return -EFAULT; - - rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version, - SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len, - &arg->fw_err); - if (rc) - return rc; - - memcpy(resp.data, buf, sizeof(resp.data)); - if (copy_to_user((void __user *)arg->resp_data, &resp, sizeof(resp))) - rc = -EFAULT; - - /* The response buffer contains the sensitive data, explicitly clear it. */ - memzero_explicit(buf, sizeof(buf)); - memzero_explicit(&resp, sizeof(resp)); - return rc; -} - -static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg) -{ - struct snp_guest_crypto *crypto = snp_dev->crypto; - struct snp_ext_report_req req; - struct snp_report_resp *resp; - int ret, npages = 0, resp_len; - - lockdep_assert_held(&snp_cmd_mutex); - - if (!arg->req_data || !arg->resp_data) - return -EINVAL; - - if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req))) - return -EFAULT; - - /* userspace does not want certificate data */ - if (!req.certs_len || !req.certs_address) - goto cmd; - - if (req.certs_len > SEV_FW_BLOB_MAX_SIZE || - !IS_ALIGNED(req.certs_len, PAGE_SIZE)) - return -EINVAL; - - if (!access_ok((const void __user *)req.certs_address, req.certs_len)) - return -EFAULT; - - /* - * Initialize the intermediate buffer with all zeros. This buffer - * is used in the guest request message to get the certs blob from - * the host. If host does not supply any certs in it, then copy - * zeros to indicate that certificate data was not provided. - */ - memset(snp_dev->certs_data, 0, req.certs_len); - npages = req.certs_len >> PAGE_SHIFT; -cmd: - /* - * 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; - - snp_dev->input.data_npages = npages; - ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version, - SNP_MSG_REPORT_REQ, &req.data, - sizeof(req.data), resp->data, resp_len, &arg->fw_err); - - /* If certs length is invalid then copy the returned length */ - if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) { - req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT; - - if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req))) - ret = -EFAULT; - } - - if (ret) - goto e_free; - - if (npages && - copy_to_user((void __user *)req.certs_address, snp_dev->certs_data, - req.certs_len)) { - ret = -EFAULT; - goto e_free; - } - - if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp))) - ret = -EFAULT; - -e_free: - kfree(resp); - return ret; -} - -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_guest_request_ioctl input; - int ret = -ENOTTY; - - if (copy_from_user(&input, argp, sizeof(input))) - return -EFAULT; - - input.fw_err = 0xff; - - /* Message version must be non-zero */ - if (!input.msg_version) - return -EINVAL; - - mutex_lock(&snp_cmd_mutex); - - /* Check if the VMPCK is not empty */ - if (is_vmpck_empty(snp_dev)) { - dev_err_ratelimited(snp_dev->dev, "VMPCK is disabled\n"); - mutex_unlock(&snp_cmd_mutex); - return -ENOTTY; - } - - switch (ioctl) { - case SNP_GET_REPORT: - ret = get_report(snp_dev, &input); - break; - case SNP_GET_DERIVED_KEY: - ret = get_derived_key(snp_dev, &input); - break; - case SNP_GET_EXT_REPORT: - ret = get_ext_report(snp_dev, &input); - break; - default: - break; - } - - mutex_unlock(&snp_cmd_mutex); - - if (input.fw_err && 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; - int ret; - - if (!buf) - return; - - ret = set_memory_encrypted((unsigned long)buf, npages); - if (ret) { - WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n"); - return; - } - - __free_pages(virt_to_page(buf), get_order(sz)); -} - -static void *alloc_shared_pages(struct device *dev, 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 (!page) - return NULL; - - ret = set_memory_decrypted((unsigned long)page_address(page), npages); - if (ret) { - dev_err(dev, "failed to mark page shared, ret=%d\n", 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 u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno) -{ - u8 *key = NULL; - - switch (id) { - case 0: - *seqno = &layout->os_area.msg_seqno_0; - key = layout->vmpck0; - break; - case 1: - *seqno = &layout->os_area.msg_seqno_1; - key = layout->vmpck1; - break; - case 2: - *seqno = &layout->os_area.msg_seqno_2; - key = layout->vmpck2; - break; - case 3: - *seqno = &layout->os_area.msg_seqno_3; - key = layout->vmpck3; - break; - default: - break; - } - - return key; -} - -static int __init sev_guest_probe(struct platform_device *pdev) -{ - struct snp_secrets_page_layout *layout; - struct sev_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 sev_guest_platform_data *)dev->platform_data; - layout = (__force void *)ioremap_encrypted(data->secrets_gpa, PAGE_SIZE); - if (!layout) - return -ENODEV; - - ret = -ENOMEM; - snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL); - if (!snp_dev) - goto e_unmap; - - ret = -EINVAL; - snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno); - if (!snp_dev->vmpck) { - dev_err(dev, "invalid vmpck id %d\n", vmpck_id); - goto e_unmap; - } - - /* Verify that VMPCK is not zero. */ - if (is_vmpck_empty(snp_dev)) { - dev_err(dev, "vmpck id %d is null\n", vmpck_id); - goto e_unmap; - } - - platform_set_drvdata(pdev, snp_dev); - snp_dev->dev = dev; - snp_dev->layout = layout; - - /* Allocate the shared page used for the request and response message. */ - snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg)); - if (!snp_dev->request) - goto e_unmap; - - snp_dev->response = alloc_shared_pages(dev, sizeof(struct snp_guest_msg)); - if (!snp_dev->response) - goto e_free_request; - - snp_dev->certs_data = alloc_shared_pages(dev, SEV_FW_BLOB_MAX_SIZE); - if (!snp_dev->certs_data) - goto e_free_response; - - ret = -EIO; - snp_dev->crypto = init_crypto(snp_dev, snp_dev->vmpck, VMPCK_KEY_LEN); - if (!snp_dev->crypto) - goto e_free_cert_data; - - misc = &snp_dev->misc; - misc->minor = MISC_DYNAMIC_MINOR; - misc->name = DEVICE_NAME; - misc->fops = &snp_guest_fops; - - /* initial the input address for guest request */ - snp_dev->input.req_gpa = __pa(snp_dev->request); - snp_dev->input.resp_gpa = __pa(snp_dev->response); - snp_dev->input.data_gpa = __pa(snp_dev->certs_data); - - ret = misc_register(misc); - if (ret) - goto e_free_cert_data; - - dev_info(dev, "Initialized SEV guest driver (using vmpck_id %d)\n", vmpck_id); - return 0; - -e_free_cert_data: - free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE); -e_free_response: - free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg)); -e_free_request: - free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); -e_unmap: - iounmap(layout); - return ret; -} - -static int __exit sev_guest_remove(struct platform_device *pdev) -{ - struct snp_guest_dev *snp_dev = platform_get_drvdata(pdev); - - free_shared_pages(snp_dev->certs_data, SEV_FW_BLOB_MAX_SIZE); - free_shared_pages(snp_dev->response, sizeof(struct snp_guest_msg)); - free_shared_pages(snp_dev->request, sizeof(struct snp_guest_msg)); - deinit_crypto(snp_dev->crypto); - misc_deregister(&snp_dev->misc); - - return 0; -} - -/* - * This driver is a common SEV guest interface driver and meant to support - * any SEV guest API. As such, even though it has been introduced along with - * the SEV-SNP support, it is named "sev-guest". - */ -static struct platform_driver sev_guest_driver = { - .remove = __exit_p(sev_guest_remove), - .driver = { - .name = "sev-guest", - }, -}; - -module_platform_driver_probe(sev_guest_driver, sev_guest_probe); - -MODULE_AUTHOR("Brijesh Singh "); -MODULE_LICENSE("GPL"); -MODULE_VERSION("1.0.0"); -MODULE_DESCRIPTION("AMD SEV Guest Driver"); diff --git a/drivers/virt/coco/sevguest/sevguest.h b/drivers/virt/coco/sevguest/sevguest.h deleted file mode 100644 index d39bdd013765..000000000000 --- a/drivers/virt/coco/sevguest/sevguest.h +++ /dev/null @@ -1,98 +0,0 @@ -/* 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 __VIRT_SEVGUEST_H__ -#define __VIRT_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; - -/* - * The secrets page contains 96-bytes of reserved field that can be used by - * the guest OS. The guest OS uses the area to save the message sequence - * number for each VMPCK. - * - * See the GHCB spec section Secret page layout for the format for this area. - */ -struct secrets_os_area { - u32 msg_seqno_0; - u32 msg_seqno_1; - u32 msg_seqno_2; - u32 msg_seqno_3; - u64 ap_jump_table_pa; - u8 rsvd[40]; - u8 guest_usage[32]; -} __packed; - -#define VMPCK_KEY_LEN 32 - -/* See the SNP spec version 0.9 for secrets page format */ -struct snp_secrets_page_layout { - u32 version; - u32 imien : 1, - rsvd1 : 31; - u32 fms; - u32 rsvd2; - u8 gosvw[16]; - u8 vmpck0[VMPCK_KEY_LEN]; - u8 vmpck1[VMPCK_KEY_LEN]; - u8 vmpck2[VMPCK_KEY_LEN]; - u8 vmpck3[VMPCK_KEY_LEN]; - struct secrets_os_area os_area; - u8 rsvd3[3840]; -} __packed; - -#endif /* __VIRT_SEVGUEST_H__ */ -- cgit v1.2.3