linux/drivers/crypto/ccp/sev-dev.c
Borislav Petkov (AMD) 0ecaefb303 x86/CPU/AMD: Track SNP host status with cc_platform_*()
The host SNP worthiness can determined later, after alternatives have
been patched, in snp_rmptable_init() depending on cmdline options like
iommu=pt which is incompatible with SNP, for example.

Which means that one cannot use X86_FEATURE_SEV_SNP and will need to
have a special flag for that control.

Use that newly added CC_ATTR_HOST_SEV_SNP in the appropriate places.

Move kdump_sev_callback() to its rightful place, while at it.

Fixes: 216d106c7f ("x86/sev: Add SEV-SNP host initialization support")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Srikanth Aithal <sraithal@amd.com>
Link: https://lore.kernel.org/r/20240327154317.29909-6-bp@alien8.de
2024-04-04 10:40:30 +02:00

2386 lines
60 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* AMD Secure Encrypted Virtualization (SEV) interface
*
* Copyright (C) 2016,2019 Advanced Micro Devices, Inc.
*
* Author: Brijesh Singh <brijesh.singh@amd.com>
*/
#include <linux/bitfield.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/spinlock_types.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/hw_random.h>
#include <linux/ccp.h>
#include <linux/firmware.h>
#include <linux/panic_notifier.h>
#include <linux/gfp.h>
#include <linux/cpufeature.h>
#include <linux/fs.h>
#include <linux/fs_struct.h>
#include <linux/psp.h>
#include <linux/amd-iommu.h>
#include <asm/smp.h>
#include <asm/cacheflush.h>
#include <asm/e820/types.h>
#include <asm/sev.h>
#include "psp-dev.h"
#include "sev-dev.h"
#define DEVICE_NAME "sev"
#define SEV_FW_FILE "amd/sev.fw"
#define SEV_FW_NAME_SIZE 64
/* Minimum firmware version required for the SEV-SNP support */
#define SNP_MIN_API_MAJOR 1
#define SNP_MIN_API_MINOR 51
/*
* Maximum number of firmware-writable buffers that might be specified
* in the parameters of a legacy SEV command buffer.
*/
#define CMD_BUF_FW_WRITABLE_MAX 2
/* Leave room in the descriptor array for an end-of-list indicator. */
#define CMD_BUF_DESC_MAX (CMD_BUF_FW_WRITABLE_MAX + 1)
static DEFINE_MUTEX(sev_cmd_mutex);
static struct sev_misc_dev *misc_dev;
static int psp_cmd_timeout = 100;
module_param(psp_cmd_timeout, int, 0644);
MODULE_PARM_DESC(psp_cmd_timeout, " default timeout value, in seconds, for PSP commands");
static int psp_probe_timeout = 5;
module_param(psp_probe_timeout, int, 0644);
MODULE_PARM_DESC(psp_probe_timeout, " default timeout value, in seconds, during PSP device probe");
static char *init_ex_path;
module_param(init_ex_path, charp, 0444);
MODULE_PARM_DESC(init_ex_path, " Path for INIT_EX data; if set try INIT_EX");
static bool psp_init_on_probe = true;
module_param(psp_init_on_probe, bool, 0444);
MODULE_PARM_DESC(psp_init_on_probe, " if true, the PSP will be initialized on module init. Else the PSP will be initialized on the first command requiring it");
MODULE_FIRMWARE("amd/amd_sev_fam17h_model0xh.sbin"); /* 1st gen EPYC */
MODULE_FIRMWARE("amd/amd_sev_fam17h_model3xh.sbin"); /* 2nd gen EPYC */
MODULE_FIRMWARE("amd/amd_sev_fam19h_model0xh.sbin"); /* 3rd gen EPYC */
MODULE_FIRMWARE("amd/amd_sev_fam19h_model1xh.sbin"); /* 4th gen EPYC */
static bool psp_dead;
static int psp_timeout;
/* Trusted Memory Region (TMR):
* The TMR is a 1MB area that must be 1MB aligned. Use the page allocator
* to allocate the memory, which will return aligned memory for the specified
* allocation order.
*
* When SEV-SNP is enabled the TMR needs to be 2MB aligned and 2MB sized.
*/
#define SEV_TMR_SIZE (1024 * 1024)
#define SNP_TMR_SIZE (2 * 1024 * 1024)
static void *sev_es_tmr;
static size_t sev_es_tmr_size = SEV_TMR_SIZE;
/* INIT_EX NV Storage:
* The NV Storage is a 32Kb area and must be 4Kb page aligned. Use the page
* allocator to allocate the memory, which will return aligned memory for the
* specified allocation order.
*/
#define NV_LENGTH (32 * 1024)
static void *sev_init_ex_buffer;
/*
* SEV_DATA_RANGE_LIST:
* Array containing range of pages that firmware transitions to HV-fixed
* page state.
*/
static struct sev_data_range_list *snp_range_list;
static inline bool sev_version_greater_or_equal(u8 maj, u8 min)
{
struct sev_device *sev = psp_master->sev_data;
if (sev->api_major > maj)
return true;
if (sev->api_major == maj && sev->api_minor >= min)
return true;
return false;
}
static void sev_irq_handler(int irq, void *data, unsigned int status)
{
struct sev_device *sev = data;
int reg;
/* Check if it is command completion: */
if (!(status & SEV_CMD_COMPLETE))
return;
/* Check if it is SEV command completion: */
reg = ioread32(sev->io_regs + sev->vdata->cmdresp_reg);
if (FIELD_GET(PSP_CMDRESP_RESP, reg)) {
sev->int_rcvd = 1;
wake_up(&sev->int_queue);
}
}
static int sev_wait_cmd_ioc(struct sev_device *sev,
unsigned int *reg, unsigned int timeout)
{
int ret;
/*
* If invoked during panic handling, local interrupts are disabled,
* so the PSP command completion interrupt can't be used. Poll for
* PSP command completion instead.
*/
if (irqs_disabled()) {
unsigned long timeout_usecs = (timeout * USEC_PER_SEC) / 10;
/* Poll for SEV command completion: */
while (timeout_usecs--) {
*reg = ioread32(sev->io_regs + sev->vdata->cmdresp_reg);
if (*reg & PSP_CMDRESP_RESP)
return 0;
udelay(10);
}
return -ETIMEDOUT;
}
ret = wait_event_timeout(sev->int_queue,
sev->int_rcvd, timeout * HZ);
if (!ret)
return -ETIMEDOUT;
*reg = ioread32(sev->io_regs + sev->vdata->cmdresp_reg);
return 0;
}
static int sev_cmd_buffer_len(int cmd)
{
switch (cmd) {
case SEV_CMD_INIT: return sizeof(struct sev_data_init);
case SEV_CMD_INIT_EX: return sizeof(struct sev_data_init_ex);
case SEV_CMD_SNP_SHUTDOWN_EX: return sizeof(struct sev_data_snp_shutdown_ex);
case SEV_CMD_SNP_INIT_EX: return sizeof(struct sev_data_snp_init_ex);
case SEV_CMD_PLATFORM_STATUS: return sizeof(struct sev_user_data_status);
case SEV_CMD_PEK_CSR: return sizeof(struct sev_data_pek_csr);
case SEV_CMD_PEK_CERT_IMPORT: return sizeof(struct sev_data_pek_cert_import);
case SEV_CMD_PDH_CERT_EXPORT: return sizeof(struct sev_data_pdh_cert_export);
case SEV_CMD_LAUNCH_START: return sizeof(struct sev_data_launch_start);
case SEV_CMD_LAUNCH_UPDATE_DATA: return sizeof(struct sev_data_launch_update_data);
case SEV_CMD_LAUNCH_UPDATE_VMSA: return sizeof(struct sev_data_launch_update_vmsa);
case SEV_CMD_LAUNCH_FINISH: return sizeof(struct sev_data_launch_finish);
case SEV_CMD_LAUNCH_MEASURE: return sizeof(struct sev_data_launch_measure);
case SEV_CMD_ACTIVATE: return sizeof(struct sev_data_activate);
case SEV_CMD_DEACTIVATE: return sizeof(struct sev_data_deactivate);
case SEV_CMD_DECOMMISSION: return sizeof(struct sev_data_decommission);
case SEV_CMD_GUEST_STATUS: return sizeof(struct sev_data_guest_status);
case SEV_CMD_DBG_DECRYPT: return sizeof(struct sev_data_dbg);
case SEV_CMD_DBG_ENCRYPT: return sizeof(struct sev_data_dbg);
case SEV_CMD_SEND_START: return sizeof(struct sev_data_send_start);
case SEV_CMD_SEND_UPDATE_DATA: return sizeof(struct sev_data_send_update_data);
case SEV_CMD_SEND_UPDATE_VMSA: return sizeof(struct sev_data_send_update_vmsa);
case SEV_CMD_SEND_FINISH: return sizeof(struct sev_data_send_finish);
case SEV_CMD_RECEIVE_START: return sizeof(struct sev_data_receive_start);
case SEV_CMD_RECEIVE_FINISH: return sizeof(struct sev_data_receive_finish);
case SEV_CMD_RECEIVE_UPDATE_DATA: return sizeof(struct sev_data_receive_update_data);
case SEV_CMD_RECEIVE_UPDATE_VMSA: return sizeof(struct sev_data_receive_update_vmsa);
case SEV_CMD_LAUNCH_UPDATE_SECRET: return sizeof(struct sev_data_launch_secret);
case SEV_CMD_DOWNLOAD_FIRMWARE: return sizeof(struct sev_data_download_firmware);
case SEV_CMD_GET_ID: return sizeof(struct sev_data_get_id);
case SEV_CMD_ATTESTATION_REPORT: return sizeof(struct sev_data_attestation_report);
case SEV_CMD_SEND_CANCEL: return sizeof(struct sev_data_send_cancel);
case SEV_CMD_SNP_GCTX_CREATE: return sizeof(struct sev_data_snp_addr);
case SEV_CMD_SNP_LAUNCH_START: return sizeof(struct sev_data_snp_launch_start);
case SEV_CMD_SNP_LAUNCH_UPDATE: return sizeof(struct sev_data_snp_launch_update);
case SEV_CMD_SNP_ACTIVATE: return sizeof(struct sev_data_snp_activate);
case SEV_CMD_SNP_DECOMMISSION: return sizeof(struct sev_data_snp_addr);
case SEV_CMD_SNP_PAGE_RECLAIM: return sizeof(struct sev_data_snp_page_reclaim);
case SEV_CMD_SNP_GUEST_STATUS: return sizeof(struct sev_data_snp_guest_status);
case SEV_CMD_SNP_LAUNCH_FINISH: return sizeof(struct sev_data_snp_launch_finish);
case SEV_CMD_SNP_DBG_DECRYPT: return sizeof(struct sev_data_snp_dbg);
case SEV_CMD_SNP_DBG_ENCRYPT: return sizeof(struct sev_data_snp_dbg);
case SEV_CMD_SNP_PAGE_UNSMASH: return sizeof(struct sev_data_snp_page_unsmash);
case SEV_CMD_SNP_PLATFORM_STATUS: return sizeof(struct sev_data_snp_addr);
case SEV_CMD_SNP_GUEST_REQUEST: return sizeof(struct sev_data_snp_guest_request);
case SEV_CMD_SNP_CONFIG: return sizeof(struct sev_user_data_snp_config);
case SEV_CMD_SNP_COMMIT: return sizeof(struct sev_data_snp_commit);
default: return 0;
}
return 0;
}
static struct file *open_file_as_root(const char *filename, int flags, umode_t mode)
{
struct file *fp;
struct path root;
struct cred *cred;
const struct cred *old_cred;
task_lock(&init_task);
get_fs_root(init_task.fs, &root);
task_unlock(&init_task);
cred = prepare_creds();
if (!cred)
return ERR_PTR(-ENOMEM);
cred->fsuid = GLOBAL_ROOT_UID;
old_cred = override_creds(cred);
fp = file_open_root(&root, filename, flags, mode);
path_put(&root);
revert_creds(old_cred);
return fp;
}
static int sev_read_init_ex_file(void)
{
struct sev_device *sev = psp_master->sev_data;
struct file *fp;
ssize_t nread;
lockdep_assert_held(&sev_cmd_mutex);
if (!sev_init_ex_buffer)
return -EOPNOTSUPP;
fp = open_file_as_root(init_ex_path, O_RDONLY, 0);
if (IS_ERR(fp)) {
int ret = PTR_ERR(fp);
if (ret == -ENOENT) {
dev_info(sev->dev,
"SEV: %s does not exist and will be created later.\n",
init_ex_path);
ret = 0;
} else {
dev_err(sev->dev,
"SEV: could not open %s for read, error %d\n",
init_ex_path, ret);
}
return ret;
}
nread = kernel_read(fp, sev_init_ex_buffer, NV_LENGTH, NULL);
if (nread != NV_LENGTH) {
dev_info(sev->dev,
"SEV: could not read %u bytes to non volatile memory area, ret %ld\n",
NV_LENGTH, nread);
}
dev_dbg(sev->dev, "SEV: read %ld bytes from NV file\n", nread);
filp_close(fp, NULL);
return 0;
}
static int sev_write_init_ex_file(void)
{
struct sev_device *sev = psp_master->sev_data;
struct file *fp;
loff_t offset = 0;
ssize_t nwrite;
lockdep_assert_held(&sev_cmd_mutex);
if (!sev_init_ex_buffer)
return 0;
fp = open_file_as_root(init_ex_path, O_CREAT | O_WRONLY, 0600);
if (IS_ERR(fp)) {
int ret = PTR_ERR(fp);
dev_err(sev->dev,
"SEV: could not open file for write, error %d\n",
ret);
return ret;
}
nwrite = kernel_write(fp, sev_init_ex_buffer, NV_LENGTH, &offset);
vfs_fsync(fp, 0);
filp_close(fp, NULL);
if (nwrite != NV_LENGTH) {
dev_err(sev->dev,
"SEV: failed to write %u bytes to non volatile memory area, ret %ld\n",
NV_LENGTH, nwrite);
return -EIO;
}
dev_dbg(sev->dev, "SEV: write successful to NV file\n");
return 0;
}
static int sev_write_init_ex_file_if_required(int cmd_id)
{
lockdep_assert_held(&sev_cmd_mutex);
if (!sev_init_ex_buffer)
return 0;
/*
* Only a few platform commands modify the SPI/NV area, but none of the
* non-platform commands do. Only INIT(_EX), PLATFORM_RESET, PEK_GEN,
* PEK_CERT_IMPORT, and PDH_GEN do.
*/
switch (cmd_id) {
case SEV_CMD_FACTORY_RESET:
case SEV_CMD_INIT_EX:
case SEV_CMD_PDH_GEN:
case SEV_CMD_PEK_CERT_IMPORT:
case SEV_CMD_PEK_GEN:
break;
default:
return 0;
}
return sev_write_init_ex_file();
}
/*
* snp_reclaim_pages() needs __sev_do_cmd_locked(), and __sev_do_cmd_locked()
* needs snp_reclaim_pages(), so a forward declaration is needed.
*/
static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret);
static int snp_reclaim_pages(unsigned long paddr, unsigned int npages, bool locked)
{
int ret, err, i;
paddr = __sme_clr(ALIGN_DOWN(paddr, PAGE_SIZE));
for (i = 0; i < npages; i++, paddr += PAGE_SIZE) {
struct sev_data_snp_page_reclaim data = {0};
data.paddr = paddr;
if (locked)
ret = __sev_do_cmd_locked(SEV_CMD_SNP_PAGE_RECLAIM, &data, &err);
else
ret = sev_do_cmd(SEV_CMD_SNP_PAGE_RECLAIM, &data, &err);
if (ret)
goto cleanup;
ret = rmp_make_shared(__phys_to_pfn(paddr), PG_LEVEL_4K);
if (ret)
goto cleanup;
}
return 0;
cleanup:
/*
* If there was a failure reclaiming the page then it is no longer safe
* to release it back to the system; leak it instead.
*/
snp_leak_pages(__phys_to_pfn(paddr), npages - i);
return ret;
}
static int rmp_mark_pages_firmware(unsigned long paddr, unsigned int npages, bool locked)
{
unsigned long pfn = __sme_clr(paddr) >> PAGE_SHIFT;
int rc, i;
for (i = 0; i < npages; i++, pfn++) {
rc = rmp_make_private(pfn, 0, PG_LEVEL_4K, 0, true);
if (rc)
goto cleanup;
}
return 0;
cleanup:
/*
* Try unrolling the firmware state changes by
* reclaiming the pages which were already changed to the
* firmware state.
*/
snp_reclaim_pages(paddr, i, locked);
return rc;
}
static struct page *__snp_alloc_firmware_pages(gfp_t gfp_mask, int order)
{
unsigned long npages = 1ul << order, paddr;
struct sev_device *sev;
struct page *page;
if (!psp_master || !psp_master->sev_data)
return NULL;
page = alloc_pages(gfp_mask, order);
if (!page)
return NULL;
/* If SEV-SNP is initialized then add the page in RMP table. */
sev = psp_master->sev_data;
if (!sev->snp_initialized)
return page;
paddr = __pa((unsigned long)page_address(page));
if (rmp_mark_pages_firmware(paddr, npages, false))
return NULL;
return page;
}
void *snp_alloc_firmware_page(gfp_t gfp_mask)
{
struct page *page;
page = __snp_alloc_firmware_pages(gfp_mask, 0);
return page ? page_address(page) : NULL;
}
EXPORT_SYMBOL_GPL(snp_alloc_firmware_page);
static void __snp_free_firmware_pages(struct page *page, int order, bool locked)
{
struct sev_device *sev = psp_master->sev_data;
unsigned long paddr, npages = 1ul << order;
if (!page)
return;
paddr = __pa((unsigned long)page_address(page));
if (sev->snp_initialized &&
snp_reclaim_pages(paddr, npages, locked))
return;
__free_pages(page, order);
}
void snp_free_firmware_page(void *addr)
{
if (!addr)
return;
__snp_free_firmware_pages(virt_to_page(addr), 0, false);
}
EXPORT_SYMBOL_GPL(snp_free_firmware_page);
static void *sev_fw_alloc(unsigned long len)
{
struct page *page;
page = __snp_alloc_firmware_pages(GFP_KERNEL, get_order(len));
if (!page)
return NULL;
return page_address(page);
}
/**
* struct cmd_buf_desc - descriptors for managing legacy SEV command address
* parameters corresponding to buffers that may be written to by firmware.
*
* @paddr_ptr: pointer to the address parameter in the command buffer which may
* need to be saved/restored depending on whether a bounce buffer
* is used. In the case of a bounce buffer, the command buffer
* needs to be updated with the address of the new bounce buffer
* snp_map_cmd_buf_desc() has allocated specifically for it. Must
* be NULL if this descriptor is only an end-of-list indicator.
*
* @paddr_orig: storage for the original address parameter, which can be used to
* restore the original value in @paddr_ptr in cases where it is
* replaced with the address of a bounce buffer.
*
* @len: length of buffer located at the address originally stored at @paddr_ptr
*
* @guest_owned: true if the address corresponds to guest-owned pages, in which
* case bounce buffers are not needed.
*/
struct cmd_buf_desc {
u64 *paddr_ptr;
u64 paddr_orig;
u32 len;
bool guest_owned;
};
/*
* If a legacy SEV command parameter is a memory address, those pages in
* turn need to be transitioned to/from firmware-owned before/after
* executing the firmware command.
*
* Additionally, in cases where those pages are not guest-owned, a bounce
* buffer is needed in place of the original memory address parameter.
*
* A set of descriptors are used to keep track of this handling, and
* initialized here based on the specific commands being executed.
*/
static void snp_populate_cmd_buf_desc_list(int cmd, void *cmd_buf,
struct cmd_buf_desc *desc_list)
{
switch (cmd) {
case SEV_CMD_PDH_CERT_EXPORT: {
struct sev_data_pdh_cert_export *data = cmd_buf;
desc_list[0].paddr_ptr = &data->pdh_cert_address;
desc_list[0].len = data->pdh_cert_len;
desc_list[1].paddr_ptr = &data->cert_chain_address;
desc_list[1].len = data->cert_chain_len;
break;
}
case SEV_CMD_GET_ID: {
struct sev_data_get_id *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
break;
}
case SEV_CMD_PEK_CSR: {
struct sev_data_pek_csr *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
break;
}
case SEV_CMD_LAUNCH_UPDATE_DATA: {
struct sev_data_launch_update_data *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_LAUNCH_UPDATE_VMSA: {
struct sev_data_launch_update_vmsa *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_LAUNCH_MEASURE: {
struct sev_data_launch_measure *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
break;
}
case SEV_CMD_LAUNCH_UPDATE_SECRET: {
struct sev_data_launch_secret *data = cmd_buf;
desc_list[0].paddr_ptr = &data->guest_address;
desc_list[0].len = data->guest_len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_DBG_DECRYPT: {
struct sev_data_dbg *data = cmd_buf;
desc_list[0].paddr_ptr = &data->dst_addr;
desc_list[0].len = data->len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_DBG_ENCRYPT: {
struct sev_data_dbg *data = cmd_buf;
desc_list[0].paddr_ptr = &data->dst_addr;
desc_list[0].len = data->len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_ATTESTATION_REPORT: {
struct sev_data_attestation_report *data = cmd_buf;
desc_list[0].paddr_ptr = &data->address;
desc_list[0].len = data->len;
break;
}
case SEV_CMD_SEND_START: {
struct sev_data_send_start *data = cmd_buf;
desc_list[0].paddr_ptr = &data->session_address;
desc_list[0].len = data->session_len;
break;
}
case SEV_CMD_SEND_UPDATE_DATA: {
struct sev_data_send_update_data *data = cmd_buf;
desc_list[0].paddr_ptr = &data->hdr_address;
desc_list[0].len = data->hdr_len;
desc_list[1].paddr_ptr = &data->trans_address;
desc_list[1].len = data->trans_len;
break;
}
case SEV_CMD_SEND_UPDATE_VMSA: {
struct sev_data_send_update_vmsa *data = cmd_buf;
desc_list[0].paddr_ptr = &data->hdr_address;
desc_list[0].len = data->hdr_len;
desc_list[1].paddr_ptr = &data->trans_address;
desc_list[1].len = data->trans_len;
break;
}
case SEV_CMD_RECEIVE_UPDATE_DATA: {
struct sev_data_receive_update_data *data = cmd_buf;
desc_list[0].paddr_ptr = &data->guest_address;
desc_list[0].len = data->guest_len;
desc_list[0].guest_owned = true;
break;
}
case SEV_CMD_RECEIVE_UPDATE_VMSA: {
struct sev_data_receive_update_vmsa *data = cmd_buf;
desc_list[0].paddr_ptr = &data->guest_address;
desc_list[0].len = data->guest_len;
desc_list[0].guest_owned = true;
break;
}
default:
break;
}
}
static int snp_map_cmd_buf_desc(struct cmd_buf_desc *desc)
{
unsigned int npages;
if (!desc->len)
return 0;
/* Allocate a bounce buffer if this isn't a guest owned page. */
if (!desc->guest_owned) {
struct page *page;
page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(desc->len));
if (!page) {
pr_warn("Failed to allocate bounce buffer for SEV legacy command.\n");
return -ENOMEM;
}
desc->paddr_orig = *desc->paddr_ptr;
*desc->paddr_ptr = __psp_pa(page_to_virt(page));
}
npages = PAGE_ALIGN(desc->len) >> PAGE_SHIFT;
/* Transition the buffer to firmware-owned. */
if (rmp_mark_pages_firmware(*desc->paddr_ptr, npages, true)) {
pr_warn("Error moving pages to firmware-owned state for SEV legacy command.\n");
return -EFAULT;
}
return 0;
}
static int snp_unmap_cmd_buf_desc(struct cmd_buf_desc *desc)
{
unsigned int npages;
if (!desc->len)
return 0;
npages = PAGE_ALIGN(desc->len) >> PAGE_SHIFT;
/* Transition the buffers back to hypervisor-owned. */
if (snp_reclaim_pages(*desc->paddr_ptr, npages, true)) {
pr_warn("Failed to reclaim firmware-owned pages while issuing SEV legacy command.\n");
return -EFAULT;
}
/* Copy data from bounce buffer and then free it. */
if (!desc->guest_owned) {
void *bounce_buf = __va(__sme_clr(*desc->paddr_ptr));
void *dst_buf = __va(__sme_clr(desc->paddr_orig));
memcpy(dst_buf, bounce_buf, desc->len);
__free_pages(virt_to_page(bounce_buf), get_order(desc->len));
/* Restore the original address in the command buffer. */
*desc->paddr_ptr = desc->paddr_orig;
}
return 0;
}
static int snp_map_cmd_buf_desc_list(int cmd, void *cmd_buf, struct cmd_buf_desc *desc_list)
{
int i;
snp_populate_cmd_buf_desc_list(cmd, cmd_buf, desc_list);
for (i = 0; i < CMD_BUF_DESC_MAX; i++) {
struct cmd_buf_desc *desc = &desc_list[i];
if (!desc->paddr_ptr)
break;
if (snp_map_cmd_buf_desc(desc))
goto err_unmap;
}
return 0;
err_unmap:
for (i--; i >= 0; i--)
snp_unmap_cmd_buf_desc(&desc_list[i]);
return -EFAULT;
}
static int snp_unmap_cmd_buf_desc_list(struct cmd_buf_desc *desc_list)
{
int i, ret = 0;
for (i = 0; i < CMD_BUF_DESC_MAX; i++) {
struct cmd_buf_desc *desc = &desc_list[i];
if (!desc->paddr_ptr)
break;
if (snp_unmap_cmd_buf_desc(&desc_list[i]))
ret = -EFAULT;
}
return ret;
}
static bool sev_cmd_buf_writable(int cmd)
{
switch (cmd) {
case SEV_CMD_PLATFORM_STATUS:
case SEV_CMD_GUEST_STATUS:
case SEV_CMD_LAUNCH_START:
case SEV_CMD_RECEIVE_START:
case SEV_CMD_LAUNCH_MEASURE:
case SEV_CMD_SEND_START:
case SEV_CMD_SEND_UPDATE_DATA:
case SEV_CMD_SEND_UPDATE_VMSA:
case SEV_CMD_PEK_CSR:
case SEV_CMD_PDH_CERT_EXPORT:
case SEV_CMD_GET_ID:
case SEV_CMD_ATTESTATION_REPORT:
return true;
default:
return false;
}
}
/* After SNP is INIT'ed, the behavior of legacy SEV commands is changed. */
static bool snp_legacy_handling_needed(int cmd)
{
struct sev_device *sev = psp_master->sev_data;
return cmd < SEV_CMD_SNP_INIT && sev->snp_initialized;
}
static int snp_prep_cmd_buf(int cmd, void *cmd_buf, struct cmd_buf_desc *desc_list)
{
if (!snp_legacy_handling_needed(cmd))
return 0;
if (snp_map_cmd_buf_desc_list(cmd, cmd_buf, desc_list))
return -EFAULT;
/*
* Before command execution, the command buffer needs to be put into
* the firmware-owned state.
*/
if (sev_cmd_buf_writable(cmd)) {
if (rmp_mark_pages_firmware(__pa(cmd_buf), 1, true))
return -EFAULT;
}
return 0;
}
static int snp_reclaim_cmd_buf(int cmd, void *cmd_buf)
{
if (!snp_legacy_handling_needed(cmd))
return 0;
/*
* After command completion, the command buffer needs to be put back
* into the hypervisor-owned state.
*/
if (sev_cmd_buf_writable(cmd))
if (snp_reclaim_pages(__pa(cmd_buf), 1, true))
return -EFAULT;
return 0;
}
static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
{
struct cmd_buf_desc desc_list[CMD_BUF_DESC_MAX] = {0};
struct psp_device *psp = psp_master;
struct sev_device *sev;
unsigned int cmdbuff_hi, cmdbuff_lo;
unsigned int phys_lsb, phys_msb;
unsigned int reg, ret = 0;
void *cmd_buf;
int buf_len;
if (!psp || !psp->sev_data)
return -ENODEV;
if (psp_dead)
return -EBUSY;
sev = psp->sev_data;
buf_len = sev_cmd_buffer_len(cmd);
if (WARN_ON_ONCE(!data != !buf_len))
return -EINVAL;
/*
* Copy the incoming data to driver's scratch buffer as __pa() will not
* work for some memory, e.g. vmalloc'd addresses, and @data may not be
* physically contiguous.
*/
if (data) {
/*
* Commands are generally issued one at a time and require the
* sev_cmd_mutex, but there could be recursive firmware requests
* due to SEV_CMD_SNP_PAGE_RECLAIM needing to be issued while
* preparing buffers for another command. This is the only known
* case of nesting in the current code, so exactly one
* additional command buffer is available for that purpose.
*/
if (!sev->cmd_buf_active) {
cmd_buf = sev->cmd_buf;
sev->cmd_buf_active = true;
} else if (!sev->cmd_buf_backup_active) {
cmd_buf = sev->cmd_buf_backup;
sev->cmd_buf_backup_active = true;
} else {
dev_err(sev->dev,
"SEV: too many firmware commands in progress, no command buffers available.\n");
return -EBUSY;
}
memcpy(cmd_buf, data, buf_len);
/*
* The behavior of the SEV-legacy commands is altered when the
* SNP firmware is in the INIT state.
*/
ret = snp_prep_cmd_buf(cmd, cmd_buf, desc_list);
if (ret) {
dev_err(sev->dev,
"SEV: failed to prepare buffer for legacy command 0x%x. Error: %d\n",
cmd, ret);
return ret;
}
} else {
cmd_buf = sev->cmd_buf;
}
/* Get the physical address of the command buffer */
phys_lsb = data ? lower_32_bits(__psp_pa(cmd_buf)) : 0;
phys_msb = data ? upper_32_bits(__psp_pa(cmd_buf)) : 0;
dev_dbg(sev->dev, "sev command id %#x buffer 0x%08x%08x timeout %us\n",
cmd, phys_msb, phys_lsb, psp_timeout);
print_hex_dump_debug("(in): ", DUMP_PREFIX_OFFSET, 16, 2, data,
buf_len, false);
iowrite32(phys_lsb, sev->io_regs + sev->vdata->cmdbuff_addr_lo_reg);
iowrite32(phys_msb, sev->io_regs + sev->vdata->cmdbuff_addr_hi_reg);
sev->int_rcvd = 0;
reg = FIELD_PREP(SEV_CMDRESP_CMD, cmd) | SEV_CMDRESP_IOC;
iowrite32(reg, sev->io_regs + sev->vdata->cmdresp_reg);
/* wait for command completion */
ret = sev_wait_cmd_ioc(sev, &reg, psp_timeout);
if (ret) {
if (psp_ret)
*psp_ret = 0;
dev_err(sev->dev, "sev command %#x timed out, disabling PSP\n", cmd);
psp_dead = true;
return ret;
}
psp_timeout = psp_cmd_timeout;
if (psp_ret)
*psp_ret = FIELD_GET(PSP_CMDRESP_STS, reg);
if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
dev_dbg(sev->dev, "sev command %#x failed (%#010lx)\n",
cmd, FIELD_GET(PSP_CMDRESP_STS, reg));
/*
* PSP firmware may report additional error information in the
* command buffer registers on error. Print contents of command
* buffer registers if they changed.
*/
cmdbuff_hi = ioread32(sev->io_regs + sev->vdata->cmdbuff_addr_hi_reg);
cmdbuff_lo = ioread32(sev->io_regs + sev->vdata->cmdbuff_addr_lo_reg);
if (cmdbuff_hi != phys_msb || cmdbuff_lo != phys_lsb) {
dev_dbg(sev->dev, "Additional error information reported in cmdbuff:");
dev_dbg(sev->dev, " cmdbuff hi: %#010x\n", cmdbuff_hi);
dev_dbg(sev->dev, " cmdbuff lo: %#010x\n", cmdbuff_lo);
}
ret = -EIO;
} else {
ret = sev_write_init_ex_file_if_required(cmd);
}
/*
* Copy potential output from the PSP back to data. Do this even on
* failure in case the caller wants to glean something from the error.
*/
if (data) {
int ret_reclaim;
/*
* Restore the page state after the command completes.
*/
ret_reclaim = snp_reclaim_cmd_buf(cmd, cmd_buf);
if (ret_reclaim) {
dev_err(sev->dev,
"SEV: failed to reclaim buffer for legacy command %#x. Error: %d\n",
cmd, ret_reclaim);
return ret_reclaim;
}
memcpy(data, cmd_buf, buf_len);
if (sev->cmd_buf_backup_active)
sev->cmd_buf_backup_active = false;
else
sev->cmd_buf_active = false;
if (snp_unmap_cmd_buf_desc_list(desc_list))
return -EFAULT;
}
print_hex_dump_debug("(out): ", DUMP_PREFIX_OFFSET, 16, 2, data,
buf_len, false);
return ret;
}
int sev_do_cmd(int cmd, void *data, int *psp_ret)
{
int rc;
mutex_lock(&sev_cmd_mutex);
rc = __sev_do_cmd_locked(cmd, data, psp_ret);
mutex_unlock(&sev_cmd_mutex);
return rc;
}
EXPORT_SYMBOL_GPL(sev_do_cmd);
static int __sev_init_locked(int *error)
{
struct sev_data_init data;
memset(&data, 0, sizeof(data));
if (sev_es_tmr) {
/*
* Do not include the encryption mask on the physical
* address of the TMR (firmware should clear it anyway).
*/
data.tmr_address = __pa(sev_es_tmr);
data.flags |= SEV_INIT_FLAGS_SEV_ES;
data.tmr_len = sev_es_tmr_size;
}
return __sev_do_cmd_locked(SEV_CMD_INIT, &data, error);
}
static int __sev_init_ex_locked(int *error)
{
struct sev_data_init_ex data;
memset(&data, 0, sizeof(data));
data.length = sizeof(data);
data.nv_address = __psp_pa(sev_init_ex_buffer);
data.nv_len = NV_LENGTH;
if (sev_es_tmr) {
/*
* Do not include the encryption mask on the physical
* address of the TMR (firmware should clear it anyway).
*/
data.tmr_address = __pa(sev_es_tmr);
data.flags |= SEV_INIT_FLAGS_SEV_ES;
data.tmr_len = sev_es_tmr_size;
}
return __sev_do_cmd_locked(SEV_CMD_INIT_EX, &data, error);
}
static inline int __sev_do_init_locked(int *psp_ret)
{
if (sev_init_ex_buffer)
return __sev_init_ex_locked(psp_ret);
else
return __sev_init_locked(psp_ret);
}
static void snp_set_hsave_pa(void *arg)
{
wrmsrl(MSR_VM_HSAVE_PA, 0);
}
static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
{
struct sev_data_range_list *range_list = arg;
struct sev_data_range *range = &range_list->ranges[range_list->num_elements];
size_t size;
/*
* Ensure the list of HV_FIXED pages that will be passed to firmware
* do not exceed the page-sized argument buffer.
*/
if ((range_list->num_elements * sizeof(struct sev_data_range) +
sizeof(struct sev_data_range_list)) > PAGE_SIZE)
return -E2BIG;
switch (rs->desc) {
case E820_TYPE_RESERVED:
case E820_TYPE_PMEM:
case E820_TYPE_ACPI:
range->base = rs->start & PAGE_MASK;
size = PAGE_ALIGN((rs->end + 1) - rs->start);
range->page_count = size >> PAGE_SHIFT;
range_list->num_elements++;
break;
default:
break;
}
return 0;
}
static int __sev_snp_init_locked(int *error)
{
struct psp_device *psp = psp_master;
struct sev_data_snp_init_ex data;
struct sev_device *sev;
void *arg = &data;
int cmd, rc = 0;
if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return -ENODEV;
sev = psp->sev_data;
if (sev->snp_initialized)
return 0;
if (!sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR)) {
dev_dbg(sev->dev, "SEV-SNP support requires firmware version >= %d:%d\n",
SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR);
return 0;
}
/* SNP_INIT requires MSR_VM_HSAVE_PA to be cleared on all CPUs. */
on_each_cpu(snp_set_hsave_pa, NULL, 1);
/*
* Starting in SNP firmware v1.52, the SNP_INIT_EX command takes a list
* of system physical address ranges to convert into HV-fixed page
* states during the RMP initialization. For instance, the memory that
* UEFI reserves should be included in the that list. This allows system
* components that occasionally write to memory (e.g. logging to UEFI
* reserved regions) to not fail due to RMP initialization and SNP
* enablement.
*
*/
if (sev_version_greater_or_equal(SNP_MIN_API_MAJOR, 52)) {
/*
* Firmware checks that the pages containing the ranges enumerated
* in the RANGES structure are either in the default page state or in the
* firmware page state.
*/
snp_range_list = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!snp_range_list) {
dev_err(sev->dev,
"SEV: SNP_INIT_EX range list memory allocation failed\n");
return -ENOMEM;
}
/*
* Retrieve all reserved memory regions from the e820 memory map
* to be setup as HV-fixed pages.
*/
rc = walk_iomem_res_desc(IORES_DESC_NONE, IORESOURCE_MEM, 0, ~0,
snp_range_list, snp_filter_reserved_mem_regions);
if (rc) {
dev_err(sev->dev,
"SEV: SNP_INIT_EX walk_iomem_res_desc failed rc = %d\n", rc);
return rc;
}
memset(&data, 0, sizeof(data));
data.init_rmp = 1;
data.list_paddr_en = 1;
data.list_paddr = __psp_pa(snp_range_list);
cmd = SEV_CMD_SNP_INIT_EX;
} else {
cmd = SEV_CMD_SNP_INIT;
arg = NULL;
}
/*
* The following sequence must be issued before launching the first SNP
* guest to ensure all dirty cache lines are flushed, including from
* updates to the RMP table itself via the RMPUPDATE instruction:
*
* - WBINVD on all running CPUs
* - SEV_CMD_SNP_INIT[_EX] firmware command
* - WBINVD on all running CPUs
* - SEV_CMD_SNP_DF_FLUSH firmware command
*/
wbinvd_on_all_cpus();
rc = __sev_do_cmd_locked(cmd, arg, error);
if (rc)
return rc;
/* Prepare for first SNP guest launch after INIT. */
wbinvd_on_all_cpus();
rc = __sev_do_cmd_locked(SEV_CMD_SNP_DF_FLUSH, NULL, error);
if (rc)
return rc;
sev->snp_initialized = true;
dev_dbg(sev->dev, "SEV-SNP firmware initialized\n");
sev_es_tmr_size = SNP_TMR_SIZE;
return rc;
}
static void __sev_platform_init_handle_tmr(struct sev_device *sev)
{
if (sev_es_tmr)
return;
/* Obtain the TMR memory area for SEV-ES use */
sev_es_tmr = sev_fw_alloc(sev_es_tmr_size);
if (sev_es_tmr) {
/* Must flush the cache before giving it to the firmware */
if (!sev->snp_initialized)
clflush_cache_range(sev_es_tmr, sev_es_tmr_size);
} else {
dev_warn(sev->dev, "SEV: TMR allocation failed, SEV-ES support unavailable\n");
}
}
/*
* If an init_ex_path is provided allocate a buffer for the file and
* read in the contents. Additionally, if SNP is initialized, convert
* the buffer pages to firmware pages.
*/
static int __sev_platform_init_handle_init_ex_path(struct sev_device *sev)
{
struct page *page;
int rc;
if (!init_ex_path)
return 0;
if (sev_init_ex_buffer)
return 0;
page = alloc_pages(GFP_KERNEL, get_order(NV_LENGTH));
if (!page) {
dev_err(sev->dev, "SEV: INIT_EX NV memory allocation failed\n");
return -ENOMEM;
}
sev_init_ex_buffer = page_address(page);
rc = sev_read_init_ex_file();
if (rc)
return rc;
/* If SEV-SNP is initialized, transition to firmware page. */
if (sev->snp_initialized) {
unsigned long npages;
npages = 1UL << get_order(NV_LENGTH);
if (rmp_mark_pages_firmware(__pa(sev_init_ex_buffer), npages, false)) {
dev_err(sev->dev, "SEV: INIT_EX NV memory page state change failed.\n");
return -ENOMEM;
}
}
return 0;
}
static int __sev_platform_init_locked(int *error)
{
int rc, psp_ret = SEV_RET_NO_FW_CALL;
struct sev_device *sev;
if (!psp_master || !psp_master->sev_data)
return -ENODEV;
sev = psp_master->sev_data;
if (sev->state == SEV_STATE_INIT)
return 0;
__sev_platform_init_handle_tmr(sev);
rc = __sev_platform_init_handle_init_ex_path(sev);
if (rc)
return rc;
rc = __sev_do_init_locked(&psp_ret);
if (rc && psp_ret == SEV_RET_SECURE_DATA_INVALID) {
/*
* Initialization command returned an integrity check failure
* status code, meaning that firmware load and validation of SEV
* related persistent data has failed. Retrying the
* initialization function should succeed by replacing the state
* with a reset state.
*/
dev_err(sev->dev,
"SEV: retrying INIT command because of SECURE_DATA_INVALID error. Retrying once to reset PSP SEV state.");
rc = __sev_do_init_locked(&psp_ret);
}
if (error)
*error = psp_ret;
if (rc)
return rc;
sev->state = SEV_STATE_INIT;
/* Prepare for first SEV guest launch after INIT */
wbinvd_on_all_cpus();
rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, error);
if (rc)
return rc;
dev_dbg(sev->dev, "SEV firmware initialized\n");
dev_info(sev->dev, "SEV API:%d.%d build:%d\n", sev->api_major,
sev->api_minor, sev->build);
return 0;
}
static int _sev_platform_init_locked(struct sev_platform_init_args *args)
{
struct sev_device *sev;
int rc;
if (!psp_master || !psp_master->sev_data)
return -ENODEV;
sev = psp_master->sev_data;
if (sev->state == SEV_STATE_INIT)
return 0;
/*
* Legacy guests cannot be running while SNP_INIT(_EX) is executing,
* so perform SEV-SNP initialization at probe time.
*/
rc = __sev_snp_init_locked(&args->error);
if (rc && rc != -ENODEV) {
/*
* Don't abort the probe if SNP INIT failed,
* continue to initialize the legacy SEV firmware.
*/
dev_err(sev->dev, "SEV-SNP: failed to INIT rc %d, error %#x\n",
rc, args->error);
}
/* Defer legacy SEV/SEV-ES support if allowed by caller/module. */
if (args->probe && !psp_init_on_probe)
return 0;
return __sev_platform_init_locked(&args->error);
}
int sev_platform_init(struct sev_platform_init_args *args)
{
int rc;
mutex_lock(&sev_cmd_mutex);
rc = _sev_platform_init_locked(args);
mutex_unlock(&sev_cmd_mutex);
return rc;
}
EXPORT_SYMBOL_GPL(sev_platform_init);
static int __sev_platform_shutdown_locked(int *error)
{
struct psp_device *psp = psp_master;
struct sev_device *sev;
int ret;
if (!psp || !psp->sev_data)
return 0;
sev = psp->sev_data;
if (sev->state == SEV_STATE_UNINIT)
return 0;
ret = __sev_do_cmd_locked(SEV_CMD_SHUTDOWN, NULL, error);
if (ret)
return ret;
sev->state = SEV_STATE_UNINIT;
dev_dbg(sev->dev, "SEV firmware shutdown\n");
return ret;
}
static int sev_get_platform_state(int *state, int *error)
{
struct sev_user_data_status data;
int rc;
rc = __sev_do_cmd_locked(SEV_CMD_PLATFORM_STATUS, &data, error);
if (rc)
return rc;
*state = data.state;
return rc;
}
static int sev_ioctl_do_reset(struct sev_issue_cmd *argp, bool writable)
{
int state, rc;
if (!writable)
return -EPERM;
/*
* The SEV spec requires that FACTORY_RESET must be issued in
* UNINIT state. Before we go further lets check if any guest is
* active.
*
* If FW is in WORKING state then deny the request otherwise issue
* SHUTDOWN command do INIT -> UNINIT before issuing the FACTORY_RESET.
*
*/
rc = sev_get_platform_state(&state, &argp->error);
if (rc)
return rc;
if (state == SEV_STATE_WORKING)
return -EBUSY;
if (state == SEV_STATE_INIT) {
rc = __sev_platform_shutdown_locked(&argp->error);
if (rc)
return rc;
}
return __sev_do_cmd_locked(SEV_CMD_FACTORY_RESET, NULL, &argp->error);
}
static int sev_ioctl_do_platform_status(struct sev_issue_cmd *argp)
{
struct sev_user_data_status data;
int ret;
memset(&data, 0, sizeof(data));
ret = __sev_do_cmd_locked(SEV_CMD_PLATFORM_STATUS, &data, &argp->error);
if (ret)
return ret;
if (copy_to_user((void __user *)argp->data, &data, sizeof(data)))
ret = -EFAULT;
return ret;
}
static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool writable)
{
struct sev_device *sev = psp_master->sev_data;
int rc;
if (!writable)
return -EPERM;
if (sev->state == SEV_STATE_UNINIT) {
rc = __sev_platform_init_locked(&argp->error);
if (rc)
return rc;
}
return __sev_do_cmd_locked(cmd, NULL, &argp->error);
}
static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_user_data_pek_csr input;
struct sev_data_pek_csr data;
void __user *input_address;
void *blob = NULL;
int ret;
if (!writable)
return -EPERM;
if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
return -EFAULT;
memset(&data, 0, sizeof(data));
/* userspace wants to query CSR length */
if (!input.address || !input.length)
goto cmd;
/* allocate a physically contiguous buffer to store the CSR blob */
input_address = (void __user *)input.address;
if (input.length > SEV_FW_BLOB_MAX_SIZE)
return -EFAULT;
blob = kzalloc(input.length, GFP_KERNEL);
if (!blob)
return -ENOMEM;
data.address = __psp_pa(blob);
data.len = input.length;
cmd:
if (sev->state == SEV_STATE_UNINIT) {
ret = __sev_platform_init_locked(&argp->error);
if (ret)
goto e_free_blob;
}
ret = __sev_do_cmd_locked(SEV_CMD_PEK_CSR, &data, &argp->error);
/* If we query the CSR length, FW responded with expected data. */
input.length = data.len;
if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) {
ret = -EFAULT;
goto e_free_blob;
}
if (blob) {
if (copy_to_user(input_address, blob, input.length))
ret = -EFAULT;
}
e_free_blob:
kfree(blob);
return ret;
}
void *psp_copy_user_blob(u64 uaddr, u32 len)
{
if (!uaddr || !len)
return ERR_PTR(-EINVAL);
/* verify that blob length does not exceed our limit */
if (len > SEV_FW_BLOB_MAX_SIZE)
return ERR_PTR(-EINVAL);
return memdup_user((void __user *)uaddr, len);
}
EXPORT_SYMBOL_GPL(psp_copy_user_blob);
static int sev_get_api_version(void)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_user_data_status status;
int error = 0, ret;
ret = sev_platform_status(&status, &error);
if (ret) {
dev_err(sev->dev,
"SEV: failed to get status. Error: %#x\n", error);
return 1;
}
sev->api_major = status.api_major;
sev->api_minor = status.api_minor;
sev->build = status.build;
sev->state = status.state;
return 0;
}
static int sev_get_firmware(struct device *dev,
const struct firmware **firmware)
{
char fw_name_specific[SEV_FW_NAME_SIZE];
char fw_name_subset[SEV_FW_NAME_SIZE];
snprintf(fw_name_specific, sizeof(fw_name_specific),
"amd/amd_sev_fam%.2xh_model%.2xh.sbin",
boot_cpu_data.x86, boot_cpu_data.x86_model);
snprintf(fw_name_subset, sizeof(fw_name_subset),
"amd/amd_sev_fam%.2xh_model%.1xxh.sbin",
boot_cpu_data.x86, (boot_cpu_data.x86_model & 0xf0) >> 4);
/* Check for SEV FW for a particular model.
* Ex. amd_sev_fam17h_model00h.sbin for Family 17h Model 00h
*
* or
*
* Check for SEV FW common to a subset of models.
* Ex. amd_sev_fam17h_model0xh.sbin for
* Family 17h Model 00h -- Family 17h Model 0Fh
*
* or
*
* Fall-back to using generic name: sev.fw
*/
if ((firmware_request_nowarn(firmware, fw_name_specific, dev) >= 0) ||
(firmware_request_nowarn(firmware, fw_name_subset, dev) >= 0) ||
(firmware_request_nowarn(firmware, SEV_FW_FILE, dev) >= 0))
return 0;
return -ENOENT;
}
/* Don't fail if SEV FW couldn't be updated. Continue with existing SEV FW */
static int sev_update_firmware(struct device *dev)
{
struct sev_data_download_firmware *data;
const struct firmware *firmware;
int ret, error, order;
struct page *p;
u64 data_size;
if (!sev_version_greater_or_equal(0, 15)) {
dev_dbg(dev, "DOWNLOAD_FIRMWARE not supported\n");
return -1;
}
if (sev_get_firmware(dev, &firmware) == -ENOENT) {
dev_dbg(dev, "No SEV firmware file present\n");
return -1;
}
/*
* SEV FW expects the physical address given to it to be 32
* byte aligned. Memory allocated has structure placed at the
* beginning followed by the firmware being passed to the SEV
* FW. Allocate enough memory for data structure + alignment
* padding + SEV FW.
*/
data_size = ALIGN(sizeof(struct sev_data_download_firmware), 32);
order = get_order(firmware->size + data_size);
p = alloc_pages(GFP_KERNEL, order);
if (!p) {
ret = -1;
goto fw_err;
}
/*
* Copy firmware data to a kernel allocated contiguous
* memory region.
*/
data = page_address(p);
memcpy(page_address(p) + data_size, firmware->data, firmware->size);
data->address = __psp_pa(page_address(p) + data_size);
data->len = firmware->size;
ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, data, &error);
/*
* A quirk for fixing the committed TCB version, when upgrading from
* earlier firmware version than 1.50.
*/
if (!ret && !sev_version_greater_or_equal(1, 50))
ret = sev_do_cmd(SEV_CMD_DOWNLOAD_FIRMWARE, data, &error);
if (ret)
dev_dbg(dev, "Failed to update SEV firmware: %#x\n", error);
else
dev_info(dev, "SEV firmware update successful\n");
__free_pages(p, order);
fw_err:
release_firmware(firmware);
return ret;
}
static int __sev_snp_shutdown_locked(int *error, bool panic)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_data_snp_shutdown_ex data;
int ret;
if (!sev->snp_initialized)
return 0;
memset(&data, 0, sizeof(data));
data.len = sizeof(data);
data.iommu_snp_shutdown = 1;
/*
* If invoked during panic handling, local interrupts are disabled
* and all CPUs are stopped, so wbinvd_on_all_cpus() can't be called.
* In that case, a wbinvd() is done on remote CPUs via the NMI
* callback, so only a local wbinvd() is needed here.
*/
if (!panic)
wbinvd_on_all_cpus();
else
wbinvd();
ret = __sev_do_cmd_locked(SEV_CMD_SNP_SHUTDOWN_EX, &data, error);
/* SHUTDOWN may require DF_FLUSH */
if (*error == SEV_RET_DFFLUSH_REQUIRED) {
ret = __sev_do_cmd_locked(SEV_CMD_SNP_DF_FLUSH, NULL, NULL);
if (ret) {
dev_err(sev->dev, "SEV-SNP DF_FLUSH failed\n");
return ret;
}
/* reissue the shutdown command */
ret = __sev_do_cmd_locked(SEV_CMD_SNP_SHUTDOWN_EX, &data,
error);
}
if (ret) {
dev_err(sev->dev, "SEV-SNP firmware shutdown failed\n");
return ret;
}
/*
* SNP_SHUTDOWN_EX with IOMMU_SNP_SHUTDOWN set to 1 disables SNP
* enforcement by the IOMMU and also transitions all pages
* associated with the IOMMU to the Reclaim state.
* Firmware was transitioning the IOMMU pages to Hypervisor state
* before version 1.53. But, accounting for the number of assigned
* 4kB pages in a 2M page was done incorrectly by not transitioning
* to the Reclaim state. This resulted in RMP #PF when later accessing
* the 2M page containing those pages during kexec boot. Hence, the
* firmware now transitions these pages to Reclaim state and hypervisor
* needs to transition these pages to shared state. SNP Firmware
* version 1.53 and above are needed for kexec boot.
*/
ret = amd_iommu_snp_disable();
if (ret) {
dev_err(sev->dev, "SNP IOMMU shutdown failed\n");
return ret;
}
sev->snp_initialized = false;
dev_dbg(sev->dev, "SEV-SNP firmware shutdown\n");
return ret;
}
static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_user_data_pek_cert_import input;
struct sev_data_pek_cert_import data;
void *pek_blob, *oca_blob;
int ret;
if (!writable)
return -EPERM;
if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
return -EFAULT;
/* copy PEK certificate blobs from userspace */
pek_blob = psp_copy_user_blob(input.pek_cert_address, input.pek_cert_len);
if (IS_ERR(pek_blob))
return PTR_ERR(pek_blob);
data.reserved = 0;
data.pek_cert_address = __psp_pa(pek_blob);
data.pek_cert_len = input.pek_cert_len;
/* copy PEK certificate blobs from userspace */
oca_blob = psp_copy_user_blob(input.oca_cert_address, input.oca_cert_len);
if (IS_ERR(oca_blob)) {
ret = PTR_ERR(oca_blob);
goto e_free_pek;
}
data.oca_cert_address = __psp_pa(oca_blob);
data.oca_cert_len = input.oca_cert_len;
/* If platform is not in INIT state then transition it to INIT */
if (sev->state != SEV_STATE_INIT) {
ret = __sev_platform_init_locked(&argp->error);
if (ret)
goto e_free_oca;
}
ret = __sev_do_cmd_locked(SEV_CMD_PEK_CERT_IMPORT, &data, &argp->error);
e_free_oca:
kfree(oca_blob);
e_free_pek:
kfree(pek_blob);
return ret;
}
static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
{
struct sev_user_data_get_id2 input;
struct sev_data_get_id data;
void __user *input_address;
void *id_blob = NULL;
int ret;
/* SEV GET_ID is available from SEV API v0.16 and up */
if (!sev_version_greater_or_equal(0, 16))
return -ENOTSUPP;
if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
return -EFAULT;
input_address = (void __user *)input.address;
if (input.address && input.length) {
/*
* The length of the ID shouldn't be assumed by software since
* it may change in the future. The allocation size is limited
* to 1 << (PAGE_SHIFT + MAX_PAGE_ORDER) by the page allocator.
* If the allocation fails, simply return ENOMEM rather than
* warning in the kernel log.
*/
id_blob = kzalloc(input.length, GFP_KERNEL | __GFP_NOWARN);
if (!id_blob)
return -ENOMEM;
data.address = __psp_pa(id_blob);
data.len = input.length;
} else {
data.address = 0;
data.len = 0;
}
ret = __sev_do_cmd_locked(SEV_CMD_GET_ID, &data, &argp->error);
/*
* Firmware will return the length of the ID value (either the minimum
* required length or the actual length written), return it to the user.
*/
input.length = data.len;
if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) {
ret = -EFAULT;
goto e_free;
}
if (id_blob) {
if (copy_to_user(input_address, id_blob, data.len)) {
ret = -EFAULT;
goto e_free;
}
}
e_free:
kfree(id_blob);
return ret;
}
static int sev_ioctl_do_get_id(struct sev_issue_cmd *argp)
{
struct sev_data_get_id *data;
u64 data_size, user_size;
void *id_blob, *mem;
int ret;
/* SEV GET_ID available from SEV API v0.16 and up */
if (!sev_version_greater_or_equal(0, 16))
return -ENOTSUPP;
/* SEV FW expects the buffer it fills with the ID to be
* 8-byte aligned. Memory allocated should be enough to
* hold data structure + alignment padding + memory
* where SEV FW writes the ID.
*/
data_size = ALIGN(sizeof(struct sev_data_get_id), 8);
user_size = sizeof(struct sev_user_data_get_id);
mem = kzalloc(data_size + user_size, GFP_KERNEL);
if (!mem)
return -ENOMEM;
data = mem;
id_blob = mem + data_size;
data->address = __psp_pa(id_blob);
data->len = user_size;
ret = __sev_do_cmd_locked(SEV_CMD_GET_ID, data, &argp->error);
if (!ret) {
if (copy_to_user((void __user *)argp->data, id_blob, data->len))
ret = -EFAULT;
}
kfree(mem);
return ret;
}
static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_user_data_pdh_cert_export input;
void *pdh_blob = NULL, *cert_blob = NULL;
struct sev_data_pdh_cert_export data;
void __user *input_cert_chain_address;
void __user *input_pdh_cert_address;
int ret;
/* If platform is not in INIT state then transition it to INIT. */
if (sev->state != SEV_STATE_INIT) {
if (!writable)
return -EPERM;
ret = __sev_platform_init_locked(&argp->error);
if (ret)
return ret;
}
if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
return -EFAULT;
memset(&data, 0, sizeof(data));
/* Userspace wants to query the certificate length. */
if (!input.pdh_cert_address ||
!input.pdh_cert_len ||
!input.cert_chain_address)
goto cmd;
input_pdh_cert_address = (void __user *)input.pdh_cert_address;
input_cert_chain_address = (void __user *)input.cert_chain_address;
/* Allocate a physically contiguous buffer to store the PDH blob. */
if (input.pdh_cert_len > SEV_FW_BLOB_MAX_SIZE)
return -EFAULT;
/* Allocate a physically contiguous buffer to store the cert chain blob. */
if (input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE)
return -EFAULT;
pdh_blob = kzalloc(input.pdh_cert_len, GFP_KERNEL);
if (!pdh_blob)
return -ENOMEM;
data.pdh_cert_address = __psp_pa(pdh_blob);
data.pdh_cert_len = input.pdh_cert_len;
cert_blob = kzalloc(input.cert_chain_len, GFP_KERNEL);
if (!cert_blob) {
ret = -ENOMEM;
goto e_free_pdh;
}
data.cert_chain_address = __psp_pa(cert_blob);
data.cert_chain_len = input.cert_chain_len;
cmd:
ret = __sev_do_cmd_locked(SEV_CMD_PDH_CERT_EXPORT, &data, &argp->error);
/* If we query the length, FW responded with expected data. */
input.cert_chain_len = data.cert_chain_len;
input.pdh_cert_len = data.pdh_cert_len;
if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) {
ret = -EFAULT;
goto e_free_cert;
}
if (pdh_blob) {
if (copy_to_user(input_pdh_cert_address,
pdh_blob, input.pdh_cert_len)) {
ret = -EFAULT;
goto e_free_cert;
}
}
if (cert_blob) {
if (copy_to_user(input_cert_chain_address,
cert_blob, input.cert_chain_len))
ret = -EFAULT;
}
e_free_cert:
kfree(cert_blob);
e_free_pdh:
kfree(pdh_blob);
return ret;
}
static int sev_ioctl_do_snp_platform_status(struct sev_issue_cmd *argp)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_data_snp_addr buf;
struct page *status_page;
void *data;
int ret;
if (!sev->snp_initialized || !argp->data)
return -EINVAL;
status_page = alloc_page(GFP_KERNEL_ACCOUNT);
if (!status_page)
return -ENOMEM;
data = page_address(status_page);
/*
* Firmware expects status page to be in firmware-owned state, otherwise
* it will report firmware error code INVALID_PAGE_STATE (0x1A).
*/
if (rmp_mark_pages_firmware(__pa(data), 1, true)) {
ret = -EFAULT;
goto cleanup;
}
buf.address = __psp_pa(data);
ret = __sev_do_cmd_locked(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &argp->error);
/*
* Status page will be transitioned to Reclaim state upon success, or
* left in Firmware state in failure. Use snp_reclaim_pages() to
* transition either case back to Hypervisor-owned state.
*/
if (snp_reclaim_pages(__pa(data), 1, true))
return -EFAULT;
if (ret)
goto cleanup;
if (copy_to_user((void __user *)argp->data, data,
sizeof(struct sev_user_data_snp_status)))
ret = -EFAULT;
cleanup:
__free_pages(status_page, 0);
return ret;
}
static int sev_ioctl_do_snp_commit(struct sev_issue_cmd *argp)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_data_snp_commit buf;
if (!sev->snp_initialized)
return -EINVAL;
buf.len = sizeof(buf);
return __sev_do_cmd_locked(SEV_CMD_SNP_COMMIT, &buf, &argp->error);
}
static int sev_ioctl_do_snp_set_config(struct sev_issue_cmd *argp, bool writable)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_user_data_snp_config config;
if (!sev->snp_initialized || !argp->data)
return -EINVAL;
if (!writable)
return -EPERM;
if (copy_from_user(&config, (void __user *)argp->data, sizeof(config)))
return -EFAULT;
return __sev_do_cmd_locked(SEV_CMD_SNP_CONFIG, &config, &argp->error);
}
static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
{
void __user *argp = (void __user *)arg;
struct sev_issue_cmd input;
int ret = -EFAULT;
bool writable = file->f_mode & FMODE_WRITE;
if (!psp_master || !psp_master->sev_data)
return -ENODEV;
if (ioctl != SEV_ISSUE_CMD)
return -EINVAL;
if (copy_from_user(&input, argp, sizeof(struct sev_issue_cmd)))
return -EFAULT;
if (input.cmd > SEV_MAX)
return -EINVAL;
mutex_lock(&sev_cmd_mutex);
switch (input.cmd) {
case SEV_FACTORY_RESET:
ret = sev_ioctl_do_reset(&input, writable);
break;
case SEV_PLATFORM_STATUS:
ret = sev_ioctl_do_platform_status(&input);
break;
case SEV_PEK_GEN:
ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PEK_GEN, &input, writable);
break;
case SEV_PDH_GEN:
ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PDH_GEN, &input, writable);
break;
case SEV_PEK_CSR:
ret = sev_ioctl_do_pek_csr(&input, writable);
break;
case SEV_PEK_CERT_IMPORT:
ret = sev_ioctl_do_pek_import(&input, writable);
break;
case SEV_PDH_CERT_EXPORT:
ret = sev_ioctl_do_pdh_export(&input, writable);
break;
case SEV_GET_ID:
pr_warn_once("SEV_GET_ID command is deprecated, use SEV_GET_ID2\n");
ret = sev_ioctl_do_get_id(&input);
break;
case SEV_GET_ID2:
ret = sev_ioctl_do_get_id2(&input);
break;
case SNP_PLATFORM_STATUS:
ret = sev_ioctl_do_snp_platform_status(&input);
break;
case SNP_COMMIT:
ret = sev_ioctl_do_snp_commit(&input);
break;
case SNP_SET_CONFIG:
ret = sev_ioctl_do_snp_set_config(&input, writable);
break;
default:
ret = -EINVAL;
goto out;
}
if (copy_to_user(argp, &input, sizeof(struct sev_issue_cmd)))
ret = -EFAULT;
out:
mutex_unlock(&sev_cmd_mutex);
return ret;
}
static const struct file_operations sev_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = sev_ioctl,
};
int sev_platform_status(struct sev_user_data_status *data, int *error)
{
return sev_do_cmd(SEV_CMD_PLATFORM_STATUS, data, error);
}
EXPORT_SYMBOL_GPL(sev_platform_status);
int sev_guest_deactivate(struct sev_data_deactivate *data, int *error)
{
return sev_do_cmd(SEV_CMD_DEACTIVATE, data, error);
}
EXPORT_SYMBOL_GPL(sev_guest_deactivate);
int sev_guest_activate(struct sev_data_activate *data, int *error)
{
return sev_do_cmd(SEV_CMD_ACTIVATE, data, error);
}
EXPORT_SYMBOL_GPL(sev_guest_activate);
int sev_guest_decommission(struct sev_data_decommission *data, int *error)
{
return sev_do_cmd(SEV_CMD_DECOMMISSION, data, error);
}
EXPORT_SYMBOL_GPL(sev_guest_decommission);
int sev_guest_df_flush(int *error)
{
return sev_do_cmd(SEV_CMD_DF_FLUSH, NULL, error);
}
EXPORT_SYMBOL_GPL(sev_guest_df_flush);
static void sev_exit(struct kref *ref)
{
misc_deregister(&misc_dev->misc);
kfree(misc_dev);
misc_dev = NULL;
}
static int sev_misc_init(struct sev_device *sev)
{
struct device *dev = sev->dev;
int ret;
/*
* SEV feature support can be detected on multiple devices but the SEV
* FW commands must be issued on the master. During probe, we do not
* know the master hence we create /dev/sev on the first device probe.
* sev_do_cmd() finds the right master device to which to issue the
* command to the firmware.
*/
if (!misc_dev) {
struct miscdevice *misc;
misc_dev = kzalloc(sizeof(*misc_dev), GFP_KERNEL);
if (!misc_dev)
return -ENOMEM;
misc = &misc_dev->misc;
misc->minor = MISC_DYNAMIC_MINOR;
misc->name = DEVICE_NAME;
misc->fops = &sev_fops;
ret = misc_register(misc);
if (ret)
return ret;
kref_init(&misc_dev->refcount);
} else {
kref_get(&misc_dev->refcount);
}
init_waitqueue_head(&sev->int_queue);
sev->misc = misc_dev;
dev_dbg(dev, "registered SEV device\n");
return 0;
}
int sev_dev_init(struct psp_device *psp)
{
struct device *dev = psp->dev;
struct sev_device *sev;
int ret = -ENOMEM;
if (!boot_cpu_has(X86_FEATURE_SEV)) {
dev_info_once(dev, "SEV: memory encryption not enabled by BIOS\n");
return 0;
}
sev = devm_kzalloc(dev, sizeof(*sev), GFP_KERNEL);
if (!sev)
goto e_err;
sev->cmd_buf = (void *)devm_get_free_pages(dev, GFP_KERNEL, 1);
if (!sev->cmd_buf)
goto e_sev;
sev->cmd_buf_backup = (uint8_t *)sev->cmd_buf + PAGE_SIZE;
psp->sev_data = sev;
sev->dev = dev;
sev->psp = psp;
sev->io_regs = psp->io_regs;
sev->vdata = (struct sev_vdata *)psp->vdata->sev;
if (!sev->vdata) {
ret = -ENODEV;
dev_err(dev, "sev: missing driver data\n");
goto e_buf;
}
psp_set_sev_irq_handler(psp, sev_irq_handler, sev);
ret = sev_misc_init(sev);
if (ret)
goto e_irq;
dev_notice(dev, "sev enabled\n");
return 0;
e_irq:
psp_clear_sev_irq_handler(psp);
e_buf:
devm_free_pages(dev, (unsigned long)sev->cmd_buf);
e_sev:
devm_kfree(dev, sev);
e_err:
psp->sev_data = NULL;
dev_notice(dev, "sev initialization failed\n");
return ret;
}
static void __sev_firmware_shutdown(struct sev_device *sev, bool panic)
{
int error;
__sev_platform_shutdown_locked(NULL);
if (sev_es_tmr) {
/*
* The TMR area was encrypted, flush it from the cache.
*
* If invoked during panic handling, local interrupts are
* disabled and all CPUs are stopped, so wbinvd_on_all_cpus()
* can't be used. In that case, wbinvd() is done on remote CPUs
* via the NMI callback, and done for this CPU later during
* SNP shutdown, so wbinvd_on_all_cpus() can be skipped.
*/
if (!panic)
wbinvd_on_all_cpus();
__snp_free_firmware_pages(virt_to_page(sev_es_tmr),
get_order(sev_es_tmr_size),
true);
sev_es_tmr = NULL;
}
if (sev_init_ex_buffer) {
__snp_free_firmware_pages(virt_to_page(sev_init_ex_buffer),
get_order(NV_LENGTH),
true);
sev_init_ex_buffer = NULL;
}
if (snp_range_list) {
kfree(snp_range_list);
snp_range_list = NULL;
}
__sev_snp_shutdown_locked(&error, panic);
}
static void sev_firmware_shutdown(struct sev_device *sev)
{
mutex_lock(&sev_cmd_mutex);
__sev_firmware_shutdown(sev, false);
mutex_unlock(&sev_cmd_mutex);
}
void sev_dev_destroy(struct psp_device *psp)
{
struct sev_device *sev = psp->sev_data;
if (!sev)
return;
sev_firmware_shutdown(sev);
if (sev->misc)
kref_put(&misc_dev->refcount, sev_exit);
psp_clear_sev_irq_handler(psp);
}
static int snp_shutdown_on_panic(struct notifier_block *nb,
unsigned long reason, void *arg)
{
struct sev_device *sev = psp_master->sev_data;
/*
* If sev_cmd_mutex is already acquired, then it's likely
* another PSP command is in flight and issuing a shutdown
* would fail in unexpected ways. Rather than create even
* more confusion during a panic, just bail out here.
*/
if (mutex_is_locked(&sev_cmd_mutex))
return NOTIFY_DONE;
__sev_firmware_shutdown(sev, true);
return NOTIFY_DONE;
}
static struct notifier_block snp_panic_notifier = {
.notifier_call = snp_shutdown_on_panic,
};
int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd,
void *data, int *error)
{
if (!filep || filep->f_op != &sev_fops)
return -EBADF;
return sev_do_cmd(cmd, data, error);
}
EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
void sev_pci_init(void)
{
struct sev_device *sev = psp_master->sev_data;
struct sev_platform_init_args args = {0};
int rc;
if (!sev)
return;
psp_timeout = psp_probe_timeout;
if (sev_get_api_version())
goto err;
if (sev_update_firmware(sev->dev) == 0)
sev_get_api_version();
/* Initialize the platform */
args.probe = true;
rc = sev_platform_init(&args);
if (rc)
dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
args.error, rc);
dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ?
"-SNP" : "", sev->api_major, sev->api_minor, sev->build);
atomic_notifier_chain_register(&panic_notifier_list,
&snp_panic_notifier);
return;
err:
psp_master->sev_data = NULL;
}
void sev_pci_exit(void)
{
struct sev_device *sev = psp_master->sev_data;
if (!sev)
return;
sev_firmware_shutdown(sev);
atomic_notifier_chain_unregister(&panic_notifier_list,
&snp_panic_notifier);
}