// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-20 Intel Corporation. */
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/highmem.h>
#include <linux/kthread.h>
#include <linux/kvm_types.h>
#include <linux/miscdevice.h>
#include <linux/node.h>
#include <linux/pagemap.h>
#include <linux/ratelimit.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/vmalloc.h>
#include <asm/cpuid/api.h>
#include <asm/msr.h>
#include <asm/sgx.h>
#include <asm/archrandom.h>
#include "driver.h"
#include "encl.h"
#include "encls.h"
struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];
static int sgx_nr_epc_sections;
static struct task_struct *ksgxd_tsk;
static DECLARE_WAIT_QUEUE_HEAD(ksgxd_waitq);
static DEFINE_XARRAY(sgx_epc_address_space);
/*
* These variables are part of the state of the reclaimer, and must be accessed
* with sgx_reclaimer_lock acquired.
*/
static LIST_HEAD(sgx_active_page_list);
static DEFINE_SPINLOCK(sgx_reclaimer_lock);
static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
/* Nodes with one or more EPC sections. */
static nodemask_t sgx_numa_mask;
/*
* Array with one list_head for each possible NUMA node. Each
* list contains all the sgx_epc_section's which are on that
* node.
*/
static struct sgx_numa_node *sgx_numa_nodes;
static LIST_HEAD(sgx_dirty_page_list);
/*
* Reset post-kexec EPC pages to the uninitialized state. The pages are removed
* from the input list, and made available for the page allocator. SECS pages
* prepending their children in the input list are left intact.
*
* Return 0 when sanitization was successful or kthread was stopped, and the
* number of unsanitized pages otherwise.
*/
static unsigned long __sgx_sanitize_pages(struct list_head *dirty_page_list)
{
unsigned long left_dirty = 0;
struct sgx_epc_page *page;
LIST_HEAD(dirty);
int ret;
/* dirty_page_list is thread-local, no need for a lock: */
while (!list_empty(dirty_page_list)) {
if (kthread_should_stop())
return 0;
page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);
/*
* Checking page->poison without holding the node->lock
* is racy, but losing the race (i.e. poison is set just
* after the check) just means __eremove() will be uselessly
* called for a page that sgx_free_epc_page() will put onto
* the node->sgx_poison_page_list later.
*/
if (page->poison) {
struct sgx_epc_section *section = &sgx_epc_sections[page->section];
struct sgx_numa_node *node = section->node;
spin_lock(&node->lock);
list_move(&page->list, &node->sgx_poison_page_list);
spin_unlock(&node->lock);
continue;
}
ret = __eremove(sgx_get_epc_virt_addr(page));
if (!ret) {
/*
* page is now sanitized. Make it available via the SGX
* page allocator:
*/
list_del(&page->list);
sgx_free_epc_page(page);
} else {
/* The page is not yet clean - move to the dirty list. */
list_move_tail(&page->list, &dirty);
left_dirty++;
}
cond_resched();
}
list_splice(&dirty, dirty_page_list);
return left_dirty;
}
static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page)
{
struct sgx_encl_page *page = epc_page->owner;
struct sgx_encl *encl = page->encl;
struct sgx_encl_mm *encl_mm;
bool ret = true;
int idx;
idx = srcu_read_lock(&encl->srcu);
list_for_each_entry_rcu(encl_mm, &encl->mm_list, list) {
if (!mmget_not_zero(encl_mm->mm))
continue;
mmap_read_lock(encl_mm->mm);
ret = !sgx_encl_test_and_clear_young(encl_mm->mm, page);
mmap_read_unlock(encl_mm->mm);
mmput_async(encl_mm->mm);
if (!ret)
break;
}
srcu_read_unlock(&encl->srcu, idx);
if (!ret)
return false;
return true;
}
static void sgx_reclaimer_block(struct sgx_epc_page *epc_page)
{
struct sgx_encl_page *page = epc_page->owner;
unsigned long addr = page->desc & PAGE_MASK;
struct sgx_encl *encl = page->encl;
int ret;
sgx_zap_enclave_ptes(encl, addr);
mutex_lock(&encl->lock);
ret = __eblock(sgx_get_epc_virt_addr(epc_page));
if (encls_failed(ret))
ENCLS_WARN(ret, "EBLOCK");
mutex_unlock(&encl->lock);
}
static int __sgx_encl_ewb(struct sgx_epc_page *epc_page, void *va_slot,
struct sgx_backing *backing)
{
struct sgx_pageinfo pginfo;
int ret;
pginfo.addr = 0;
pginfo.secs = 0;
pginfo.contents = (unsigned long)kmap_local_page(backing->contents);
pginfo.metadata = (unsigned long)kmap_local_page(backing->pcmd) +
backing->pcmd_offset;
ret = __ewb(&pginfo, sgx_get_epc_virt_addr(epc_page), va_slot);
set_page_dirty(backing->pcmd);
set_page_dirty(backing->contents);
kunmap_local((void *)(unsigned long)(pginfo.metadata -
backing->pcmd_offset));
kunmap_local((void *)(unsigned long)pginfo.contents);
return ret;
}
void sgx_ipi_cb(void *info)
{
}
/*
* Swap page to the regular memory transformed to the blocked state by using
* EBLOCK, which means that it can no longer be referenced (no new TLB entries).
*
* The first trial just tries to write the page assuming that some other thread
* has reset the count for threads inside the enclave by using ETRACK, and
* previous thread count has been zeroed out. The second trial calls ETRACK
* before EWB. If that fails we kick all the HW threads out, and then do EWB,
* which should be guaranteed the succeed.
*/
static void sgx_encl_ewb(struct sgx_epc_page *epc_page,
struct sgx_backing *backing)
{
struct sgx_encl_page *encl_page = epc_page->owner;
struct sgx_encl *encl = encl_page->encl;
struct sgx_va_page *va_page;
unsigned int va_offset;
void *va_slot;
int ret;
encl_page->desc &= ~SGX_ENCL_PAGE_BEING_RECLAIMED;
va_page = list_first_entry(&encl->va_pages, struct sgx_va_page,
list);
va_offset = sgx_alloc_va_slot(va_page);
va_slot = sgx_get_epc_virt_addr(va_page->epc_page) + va_offset;
if (sgx_va_page_full(va_page))
list_move_tail(&va_page->list, &encl->va_pages);
ret = __sgx_encl_ewb(epc_page, va_slot, backing);
if (ret == SGX_NOT_TRACKED) {
ret = __etrack(sgx_get_epc_virt_addr(encl->secs.epc_page));
if (ret) {
if (encls_failed(ret))
ENCLS_WARN(ret, "ETRACK");
}
ret = __sgx_encl_ewb(epc_page, va_slot, backing);
if (ret == SGX_NOT_TRACKED) {
/*
* Slow path, send IPIs to kick cpus out of the
* enclave. Note, it's imperative that the cpu
* mask is generated *after* ETRACK, else we'll
* miss cpus that entered the enclave between
* generating the mask and incrementing epoch.
*/
on_each_cpu_mask(sgx_encl_cpumask(encl),
sgx_ipi_cb, NULL, 1);
ret = __sgx_encl_ewb(epc_page, va_slot, backing);
}
}
if (ret) {
if (encls_failed(ret))
ENCLS_WARN(ret, "EWB");
sgx_free_va_slot(va_page, va_offset);
} else {
encl_page->desc |= va_offset;
encl_page->va_page = va_page;
}
}
static void sgx_reclaimer_write(struct sgx_epc_page *epc_page,
struct sgx_backing *backing)
{
struct sgx_encl_page *encl_page = epc_page->owner;
struct sgx_encl *encl = encl_page->encl;
struct sgx_backing secs_backing;
int ret;
mutex_lock(&encl->lock);
sgx_encl_ewb(epc_page, backing);
encl_page->epc_page = NULL;
encl->secs_child_cnt--;
sgx_encl_put_backing(backing);
if (!encl->secs_child_cnt && test_bit(SGX_ENCL_INITIALIZED, &encl->flags)) {
ret = sgx_encl_alloc_backing(encl, PFN_DOWN(encl->size),
&secs_backing);
if (ret)
goto out;
sgx_encl_ewb(encl->secs.epc_page, &secs_backing);
sgx_encl_free_epc_page(encl->secs.epc_page);
encl->secs.epc_page = NULL;
sgx_encl_put_backing(&secs_backing);
}
out:
mutex_unlock(&encl->lock);
}
/*
* Take a fixed number of pages from the head of the active page pool and
* reclaim them to the enclave's private shmem files. Skip the pages, which have
* been accessed since the last scan. Move those pages to the tail of active
* page pool so that the pages get scanned in LRU like fashion.
*
* Batch process a chunk of pages (at the moment 16) in order to degrade amount
* of IPI's and ETRACK's potentially required. sgx_encl_ewb() does degrade a bit
* among the HW threads with three stage EWB pipeline (EWB, ETRACK + EWB and IPI
* + EWB) but not sufficiently. Reclaiming one page at a time would also be
* problematic as it would increase the lock contention too much, which would
* halt forward progress.
*/
static void sgx_reclaim_pages(void)
{
struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
struct sgx_backing backing[SGX_NR_TO_SCAN];
struct sgx_encl_page *encl_page;
struct sgx_epc_page *epc_page;
pgoff_t page_index;
int cnt = 0;
int ret;
int i;
spin_lock(&sgx_reclaimer_lock);
for (i = 0; i < SGX_NR_TO_SCAN; i++) {
if (list_empty(&sgx_active_page_list))
break;
epc_page = list_first_entry(&sgx_active_page_list,
struct sgx_epc_page, list);
list_del_init(&epc_page->list);
encl_page = epc_page->owner;
if (kref_get_unless_zero(&encl_page->encl->refcount) != 0)
chunk[cnt++] = epc_page;
else
/* The owner is freeing the page. No need to add the
* page back to the list of reclaimable pages.
*/
epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
}
spin_unlock(&sgx_reclaimer_lock);
for (i = 0; i < cnt; i++) {
epc_page = chunk[i];
encl_page = epc_page->owner;
if (!sgx_reclaimer_age(epc_page))
goto skip;
page_index = PFN_DOWN(encl_page->desc - encl_page->encl->base);
mutex_lock(&encl_page->encl->lock);
ret = sgx_encl_alloc_backing(encl_page->encl, page_index, &backing[i]);
if (ret) {
mutex_unlock(&encl_page->encl->lock);
goto skip;
}
encl_page->desc |= SGX_ENCL_PAGE_BEING_RECLAIMED;
mutex_unlock(&encl_page->encl->lock);
continue;
skip:
spin_lock(&sgx_reclaimer_lock);
list_add_tail(&epc_page->list, &sgx_active_page_list);
spin_unlock(&sgx_reclaimer_lock);
kref_put(&encl_page->encl->refcount, sgx_encl_release);
chunk[i] = NULL;
}
for (i = 0; i < cnt; i++) {
epc_page = chunk[i];
if (epc_page)
sgx_reclaimer_block(epc_page);
}
for (i = 0; i < cnt; i++) {
epc_page = chunk[i];
if (!epc_page)
continue;
encl_page = epc_page->owner;
sgx_reclaimer_write(epc_page, &backing[i]);
kref_put(&encl_page->encl->refcount, sgx_encl_release);
epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
sgx_free_epc_page(epc_page);
}
}
static bool sgx_should_reclaim(unsigned long watermark)
{
return atomic_long_read(&sgx_nr_free_pages) < watermark &&
!list_empty(&sgx_active_page_list);
}
/*
* sgx_reclaim_direct() should be called (without enclave's mutex held)
* in locations where SGX memory resources might be low and might be
* needed in order to make forward progress.
*/
void sgx_reclaim_direct(void)
{
if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
sgx_reclaim_pages();
}
static int ksgxd(void *p)
{
set_freezable();
/*
* Sanitize pages in order to recover from kexec(). The 2nd pass is
* required for SECS pages, whose child pages blocked EREMOVE.
*/
__sgx_sanitize_pages(&sgx_dirty_page_list);
WARN_ON(__sgx_sanitize_pages(&sgx_dirty_page_list));
while (!kthread_should_stop()) {
if (try_to_freeze())
continue;
wait_event_freezable(ksgxd_waitq,
kthread_should_stop() ||
sgx_should_reclaim(SGX_NR_HIGH_PAGES));
if (sgx_should_reclaim(SGX_NR_HIGH_PAGES))
sgx_reclaim_pages();
cond_resched();
}
return 0;
}
static bool __init sgx_page_reclaimer_init(void)
{
struct task_struct *tsk;
tsk = kthread_run(ksgxd, NULL, "ksgxd");
if (IS_ERR(tsk))
return false;
ksgxd_tsk = tsk;
return true;
}
bool current_is_ksgxd(void)
{
return current == ksgxd_tsk;
}
static struct sgx_epc_page *__sgx_alloc_epc_page_from_node(int nid)
{
struct sgx_numa_node *node = &sgx_numa_nodes[nid];
struct sgx_epc_page *page = NULL;
spin_lock(&node->lock);
if (list_empty(&node->free_page_list)) {
spin_unlock(&node->lock);
return NULL;
}
page = list_first_entry(&node->free_page_list, struct sgx_epc_page, list);
list_del_init(&page->list);
page->flags = 0;
spin_unlock(&node->lock);
atomic_long_dec(&sgx_nr_free_pages);
return page;
}
/**
* __sgx_alloc_epc_page() - Allocate an EPC page
*
* Iterate through NUMA nodes and reserve ia free EPC page to the caller. Start
* from the NUMA node, where the caller is executing.
*
* Return:
* - an EPC page: A borrowed EPC pages were available.
* - NULL: Out of EPC pages.
*/
struct sgx_epc_page *__sgx_alloc_epc_page(void)
{
struct sgx_epc_page *page;
int nid_of_current = numa_node_id();
int nid_start, nid;
/*
* Try local node first. If it doesn't have an EPC section,
* fall back to the non-local NUMA nodes.
*/
if (node_isset(nid_of_current, sgx_numa_mask))
nid_start = nid_of_current;
else
nid_start = next_node_in(nid_of_current, sgx_numa_mask);
nid = nid_start;
do {
page = __sgx_alloc_epc_page_from_node(nid);
if (page)
return page;
nid = next_node_in(nid, sgx_numa_mask);
} while (nid != nid_start);
return ERR_PTR(-ENOMEM);
}
/**
* sgx_mark_page_reclaimable() - Mark a page as reclaimable
* @page: EPC page
*
* Mark a page as reclaimable and add it to the active page list. Pages
* are automatically removed from the active list when freed.
*/
void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
{
spin_lock(&sgx_reclaimer_lock);
page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
list_add_tail(&page->list, &sgx_active_page_list);
spin_unlock(&sgx_reclaimer_lock);
}
/**
* sgx_unmark_page_reclaimable() - Remove a page from the reclaim list
* @page: EPC page
*
* Clear the reclaimable flag and remove the page from the active page list.
*
* Return:
* 0 on success,
* -EBUSY if the page is in the process of being reclaimed
*/
int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
{
spin_lock(&sgx_reclaimer_lock);
if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
/* The page is being reclaimed. */
if (list_empty(&page->list)) {
spin_unlock(&sgx_reclaimer_lock);
return -EBUSY;
}
list_del(&page->list);
page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
}
spin_unlock(&sgx_reclaimer_lock);
return 0;
}
/**
* sgx_alloc_epc_page() - Allocate an EPC page
* @owner: the owner of the EPC page
* @reclaim: reclaim pages if necessary
*
* Iterate through EPC sections and borrow a free EPC page to the caller. When a
* page is no longer needed it must be released with sgx_free_epc_page(). If
* @reclaim is set to true, directly reclaim pages when we are out of pages. No
* mm's can be locked when @reclaim is set to true.
*
* Finally, wake up ksgxd when the number of pages goes below the watermark
* before returning back to the caller.
*
* Return:
* an EPC page,
* -errno on error
*/
struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool reclaim)
{
struct sgx_epc_page *page;
for ( ; ; ) {
page = __sgx_alloc_epc_page();
if (!IS_ERR(page)) {
page->owner = owner;
break;
}
if (list_empty(&sgx_active_page_list))
return ERR_PTR(-ENOMEM);
if (!reclaim) {
page = ERR_PTR(-EBUSY);
break;
}
if (signal_pending(current)) {
page = ERR_PTR(-ERESTARTSYS);
break;
}
sgx_reclaim_pages();
cond_resched();
}
if (sgx_should_reclaim(SGX_NR_LOW_PAGES))
wake_up(&ksgxd_waitq);
return page;
}
/**
* sgx_free_epc_page() - Free an EPC page
* @page: an EPC page
*
* Put the EPC page back to the list of free pages. It's the caller's
* responsibility to make sure that the page is in uninitialized state. In other
* words, do EREMOVE, EWB or whatever operation is necessary before calling
* this function.
*/
void sgx_free_epc_page(struct sgx_epc_page *page)
{
struct sgx_epc_section *section = &sgx_epc_sections[page->section];
struct sgx_numa_node *node = section->node;
spin_lock(&node->lock);
page->owner = NULL;
if (page->poison)
list_add(&page->list, &node->sgx_poison_page_list);
else
list_add_tail(&page->list, &node->free_page_list);
page->flags = SGX_EPC_PAGE_IS_FREE;
spin_unlock(&node->lock);
atomic_long_inc(&sgx_nr_free_pages);
}
static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
unsigned long index,
struct sgx_epc_section *section)
{
unsigned long nr_pages = size >> PAGE_SHIFT;
unsigned long i;
section->virt_addr = memremap(phys_addr, size, MEMREMAP_WB);
if (!section->virt_addr)
return false;
section->pages = vmalloc_array(nr_pages, sizeof(struct sgx_epc_page));
if (!section->pages) {
memunmap(section->virt_addr);
return false;
}
section->phys_addr = phys_addr;
xa_store_range(&sgx_epc_address_space, section->phys_addr,
phys_addr + size - 1, section, GFP_KERNEL);
for (i = 0; i < nr_pages; i++) {
section->pages[i].section = index;
section->pages[i].flags = 0;
section->pages[i].owner = NULL;
section->pages[i].poison = 0;
list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list);
}
return true;
}
bool arch_is_platform_page(u64 paddr)
{
return !!xa_load(&sgx_epc_address_space, paddr);
}
EXPORT_SYMBOL_GPL(arch_is_platform_page);
static struct sgx_epc_page *sgx_paddr_to_page(u64 paddr)
{
struct sgx_epc_section *section;
section = xa_load(&sgx_epc_address_space, paddr);
if (!section)
return NULL;
return §ion->pages[PFN_DOWN(paddr - section->phys_addr)];
}
/*
* Called in process context to handle a hardware reported
* error in an SGX EPC page.
* If the MF_ACTION_REQUIRED bit is set in flags, then the
* context is the task that consumed the poison data. Otherwise
* this is called from a kernel thread unrelated to the page.
*/
int arch_memory_failure(unsigned long pfn, int flags)
{
struct sgx_epc_page *page = sgx_paddr_to_page(pfn << PAGE_SHIFT);
struct sgx_epc_section *section;
struct sgx_numa_node *node;
/*
* mm/memory-failure.c calls this routine for all errors
* where there isn't a "struct page" for the address. But that
* includes other address ranges besides SGX.
*/
if (!page)
return -ENXIO;
/*
* If poison was consumed synchronously. Send a SIGBUS to
* the task. Hardware has already exited the SGX enclave and
* will not allow re-entry to an enclave that has a memory
* error. The signal may help the task understand why the
* enclave is broken.
*/
if (flags & MF_ACTION_REQUIRED)
force_sig(SIGBUS);
section = &sgx_epc_sections[page->section];
node = section->node;
spin_lock(&node->lock);
/* Already poisoned? Nothing more to do */
if (page->poison)
goto out;
page->poison = 1;
/*
* If the page is on a free list, move it to the per-node
* poison page list.
*/
if (page->flags & SGX_EPC_PAGE_IS_FREE) {
list_move(&page->list, &node->sgx_poison_page_list);
goto out;
}
sgx_unmark_page_reclaimable(page);
/*
* TBD: Add additional plumbing to enable pre-emptive
* action for asynchronous poison notification. Until
* then just hope that the poison:
* a) is not accessed - sgx_free_epc_page() will deal with it
* when the user gives it back
* b) results in a recoverable machine check rather than
* a fatal one
*/
out:
spin_unlock(&node->lock);
return 0;
}
/*
* A section metric is concatenated in a way that @low bits 12-31 define the
* bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the
* metric.
*/
static inline u64 __init sgx_calc_section_metric(u64 low, u64 high)
{
return (low & GENMASK_ULL(31, 12)) +
((high & GENMASK_ULL(19, 0)) << 32);
}
#ifdef CONFIG_NUMA
static ssize_t sgx_total_bytes_show(struct device *dev, struct device_attribute *attr, char *buf)
{
return sysfs_emit(buf, "%lu\n", sgx_numa_nodes[dev->id].size);
}
static DEVICE_ATTR_RO(sgx_total_bytes);
static umode_t arch_node_attr_is_visible(struct kobject *kobj,
struct attribute *attr, int idx)
{
/* Make all x86/ attributes invisible when SGX is not initialized: */
if (nodes_empty(sgx_numa_mask))
return 0;
return attr->mode;
}
static struct attribute *arch_node_dev_attrs[] = {
&dev_attr_sgx_total_bytes.attr,
NULL,
};
const struct attribute_group arch_node_dev_group = {
.name = "x86",
.attrs = arch_node_dev_attrs,
.is_visible = arch_node_attr_is_visible,
};
static void __init arch_update_sysfs_visibility(int nid)
{
struct node *node = node_devices[nid];
int ret;
ret = sysfs_update_group(&node->dev.kobj, &arch_node_dev_group);
if (ret)
pr_err("sysfs update failed (%d), files may be invisible", ret);
}
#else /* !CONFIG_NUMA */
static void __init arch_update_sysfs_visibility(int nid) {}
#endif
static bool __init sgx_page_cache_init(void)
{
u32 eax, ebx, ecx, edx, type;
u64 pa, size;
int nid;
int i;
sgx_numa_nodes = kmalloc_objs(*sgx_numa_nodes, num_possible_nodes());
if (!sgx_numa_nodes)
return false;
for (i = 0; i < ARRAY_SIZE(sgx_epc_sections); i++) {
cpuid_count(SGX_CPUID, i + SGX_CPUID_EPC, &eax, &ebx, &ecx, &edx);
type = eax & SGX_CPUID_EPC_MASK;
if (type == SGX_CPUID_EPC_INVALID)
break;
if (type != SGX_CPUID_EPC_SECTION) {
pr_err_once("Unknown EPC section type: %u\n", type);
break;
}
pa = sgx_calc_section_metric(eax, ebx);
size = sgx_calc_section_metric(ecx, edx);
pr_info("EPC section 0x%llx-0x%llx\n", pa, pa + size - 1);
if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i])) {
pr_err("No free memory for an EPC section\n");
break;
}
nid = numa_map_to_online_node(phys_to_target_node(pa));
if (nid == NUMA_NO_NODE) {
/* The physical address is already printed above. */
pr_warn(FW_BUG "Unable to map EPC section to online node. Fallback to the NUMA node 0.\n");
nid = 0;
}
if (!node_isset(nid, sgx_numa_mask)) {
spin_lock_init(&sgx_numa_nodes[nid].lock);
INIT_LIST_HEAD(&sgx_numa_nodes[nid].free_page_list);
INIT_LIST_HEAD(&sgx_numa_nodes[nid].sgx_poison_page_list);
node_set(nid, sgx_numa_mask);
sgx_numa_nodes[nid].size = 0;
/* Make SGX-specific node sysfs files visible: */
arch_update_sysfs_visibility(nid);
}
sgx_epc_sections[i].node = &sgx_numa_nodes[nid];
sgx_numa_nodes[nid].size += size;
sgx_nr_epc_sections++;
}
if (!sgx_nr_epc_sections) {
pr_err("There are zero EPC sections.\n");
return false;
}
for_each_online_node(nid) {
if (!node_isset(nid, sgx_numa_mask) &&
node_state(nid, N_MEMORY) && node_state(nid, N_CPU))
pr_info("node%d has both CPUs and memory but doesn't have an EPC section\n",
nid);
}
return true;
}
/*
* Update the SGX_LEPUBKEYHASH MSRs to the values specified by caller.
* Bare-metal driver requires to update them to hash of enclave's signer
* before EINIT. KVM needs to update them to guest's virtual MSR values
* before doing EINIT from guest.
*/
void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
{
int i;
WARN_ON_ONCE(preemptible());
for (i = 0; i < 4; i++)
wrmsrq(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
}
const struct file_operations sgx_provision_fops = {
.owner = THIS_MODULE,
};
static struct miscdevice sgx_dev_provision = {
.minor = MISC_DYNAMIC_MINOR,
.name = "sgx_provision",
.nodename = "sgx_provision",
.fops = &sgx_provision_fops,
};
/**
* sgx_set_attribute() - Update allowed attributes given file descriptor
* @allowed_attributes: Pointer to allowed enclave attributes
* @attribute_fd: File descriptor for specific attribute
*
* Append enclave attribute indicated by file descriptor to allowed
* attributes. Currently only SGX_ATTR_PROVISIONKEY indicated by
* /dev/sgx_provision is supported.
*
* Return:
* -0: SGX_ATTR_PROVISIONKEY is appended to allowed_attributes
* -EINVAL: Invalid, or not supported file descriptor
*/
int sgx_set_attribute(unsigned long *allowed_attributes,
unsigned int attribute_fd)
{
CLASS(fd, f)(attribute_fd);
if (fd_empty(f))
return -EINVAL;
if (fd_file(f)->f_op != &sgx_provision_fops)
return -EINVAL;
*allowed_attributes |= SGX_ATTR_PROVISIONKEY;
return 0;
}
EXPORT_SYMBOL_FOR_KVM(sgx_set_attribute);
/* Counter to count the active SGX users */
static int sgx_usage_count;
/**
* sgx_update_svn() - Attempt to call ENCLS[EUPDATESVN].
*
* This instruction attempts to update CPUSVN to the
* currently loaded microcode update SVN and generate new
* cryptographic assets.
*
* Return:
* * %0: - Success or not supported
* * %-EAGAIN: - Can be safely retried, failure is due to lack of
* * entropy in RNG
* * %-EIO: - Unexpected error, retries are not advisable
*/
static int sgx_update_svn(void)
{
int ret;
/*
* If EUPDATESVN is not available, it is ok to
* silently skip it to comply with legacy behavior.
*/
if (!cpu_feature_enabled(X86_FEATURE_SGX_EUPDATESVN))
return 0;
/*
* EPC is guaranteed to be empty when there are no users.
* Ensure we are on our first user before proceeding further.
*/
WARN(sgx_usage_count, "Elevated usage count when calling EUPDATESVN\n");
for (int i = 0; i < RDRAND_RETRY_LOOPS; i++) {
ret = __eupdatesvn();
/* Stop on success or unexpected errors: */
if (ret != SGX_INSUFFICIENT_ENTROPY)
break;
}
switch (ret) {
case 0:
/*
* SVN successfully updated.
* Let users know when the update was successful.
*/
pr_info("SVN updated successfully\n");
return 0;
case SGX_NO_UPDATE:
/*
* SVN update failed since the current SVN is
* not newer than CPUSVN. This is the most
* common case and indicates no harm.
*/
return 0;
case SGX_INSUFFICIENT_ENTROPY:
/*
* SVN update failed due to lack of entropy in DRNG.
* Indicate to userspace that it should retry.
*/
return -EAGAIN;
default:
break;
}
/*
* EUPDATESVN was called when EPC is empty, all other error
* codes are unexpected.
*/
ENCLS_WARN(ret, "EUPDATESVN");
return -EIO;
}
/* Mutex to ensure no concurrent EPC accesses during EUPDATESVN */
static DEFINE_MUTEX(sgx_svn_lock);
int sgx_inc_usage_count(void)
{
int ret;
guard(mutex)(&sgx_svn_lock);
if (!sgx_usage_count) {
ret = sgx_update_svn();
if (ret)
return ret;
}
sgx_usage_count++;
return 0;
}
void sgx_dec_usage_count(void)
{
guard(mutex)(&sgx_svn_lock);
sgx_usage_count--;
}
static int __init sgx_init(void)
{
int ret;
int i;
if (!cpu_feature_enabled(X86_FEATURE_SGX))
return -ENODEV;
if (!sgx_page_cache_init())
return -ENOMEM;
if (!sgx_page_reclaimer_init()) {
ret = -ENOMEM;
goto err_page_cache;
}
ret = misc_register(&sgx_dev_provision);
if (ret)
goto err_kthread;
/*
* Always try to initialize the native *and* KVM drivers.
* The KVM driver is less picky than the native one and
* can function if the native one is not supported on the
* current system or fails to initialize.
*
* Error out only if both fail to initialize.
*/
ret = sgx_drv_init();
if (sgx_vepc_init() && ret)
goto err_provision;
return 0;
err_provision:
misc_deregister(&sgx_dev_provision);
err_kthread:
kthread_stop(ksgxd_tsk);
err_page_cache:
for (i = 0; i < sgx_nr_epc_sections; i++) {
vfree(sgx_epc_sections[i].pages);
memunmap(sgx_epc_sections[i].virt_addr);
}
return ret;
}
device_initcall(sgx_init);
