@@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-20 Intel Corporation. */
+#include <linux/debugfs.h>
#include <linux/file.h>
#include <linux/freezer.h>
#include <linux/highmem.h>
@@ -43,6 +44,7 @@ static nodemask_t sgx_numa_mask;
static struct sgx_numa_node *sgx_numa_nodes;
static LIST_HEAD(sgx_dirty_page_list);
+static LIST_HEAD(sgx_poison_page_list);
/*
* Reset post-kexec EPC pages to the uninitialized state. The pages are removed
@@ -62,6 +64,12 @@ static void __sgx_sanitize_pages(struct list_head *dirty_page_list)
page = list_first_entry(dirty_page_list, struct sgx_epc_page, list);
+ if (page->poison) {
+ list_del(&page->list);
+ list_add(&page->list, &sgx_poison_page_list);
+ continue;
+ }
+
ret = __eremove(sgx_get_epc_virt_addr(page));
if (!ret) {
/*
@@ -626,7 +634,10 @@ void sgx_free_epc_page(struct sgx_epc_page *page)
spin_lock(&node->lock);
page->owner = NULL;
- list_add_tail(&page->list, &node->free_page_list);
+ if (page->poison)
+ list_add(&page->list, &sgx_poison_page_list);
+ else
+ list_add_tail(&page->list, &node->free_page_list);
sgx_nr_free_pages++;
spin_unlock(&node->lock);
@@ -656,6 +667,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
for (i = 0; i < nr_pages; i++) {
section->pages[i].section = index;
section->pages[i].flags = 0;
+ section->pages[i].poison = 0;
section->pages[i].owner = (void *)-1;
list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list);
}
@@ -800,8 +812,21 @@ int sgx_set_attribute(unsigned long *allowed_attributes,
}
EXPORT_SYMBOL_GPL(sgx_set_attribute);
+static int poison_list_show(struct seq_file *m, void *private)
+{
+ struct sgx_epc_page *page;
+
+ list_for_each_entry(page, &sgx_poison_page_list, list)
+ seq_printf(m, "0x%lx\n", sgx_get_epc_phys_addr(page));
+
+ return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(poison_list);
+
static int __init sgx_init(void)
{
+ struct dentry *dir;
int ret;
int i;
@@ -833,6 +858,9 @@ static int __init sgx_init(void)
if (sgx_vepc_init() && ret)
goto err_provision;
+ dir = debugfs_create_dir("sgx", arch_debugfs_dir);
+ debugfs_create_file("poison_page_list", 0400, dir, NULL, &poison_list_fops);
+
return 0;
err_provision:
@@ -28,7 +28,8 @@
struct sgx_epc_page {
unsigned int section;
- unsigned int flags;
+ u16 flags;
+ u16 poison;
void *owner;
struct list_head list;
};
A memory controller patrol scrubber can report poison in a page that isn't currently being used. Add "poison" field in the sgx_epc_page that can be set for an sgx_epc_page. Check for it: 1) When sanitizing dirty pages 2) When freeing epc pages Poison is a new field separated from flags to avoid having to make all updates to flags atomic, or integrate poison state changes into some other locking scheme to protect flags. In both cases place the poisoned page on a list of poisoned epc pages to make sure it will not be reallocated. Add debugfs files /sys/kernel/debug/sgx/poison_page_list so that system administrators get a list of those pages that have been dropped because of poison. Signed-off-by: Tony Luck <tony.luck@intel.com> --- arch/x86/kernel/cpu/sgx/main.c | 30 +++++++++++++++++++++++++++++- arch/x86/kernel/cpu/sgx/sgx.h | 3 ++- 2 files changed, 31 insertions(+), 2 deletions(-)