From: Jarkko Sakkinen <jarkko@kernel.org>
To: linux-sgx@vger.kernel.org
Cc: Haitao Huang <haitao.huang@linux.intel.com>,
Vijay Dhanraj <vijay.dhanraj@intel.com>,
Reinette Chatre <reinette.chatre@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Kai Huang <kai.huang@intel.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
AND 64-BIT))
Subject: [PATCH RFC] x86/sgx: Use a heap allocated list head for unsanitized pages
Date: Tue, 6 Sep 2022 06:12:30 +0300 [thread overview]
Message-ID: <20220906031230.107108-1-jarkko@kernel.org> (raw)
Allocate the list head for the unsanitized pages from heap, and transfer
its to ownership to ksgxd, which takes care of destroying it. Remove
sgx_dirty_page_list, as a global list is no longer required.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
Depends on https://lore.kernel.org/linux-sgx/20220906000221.34286-1-jarkko@kernel.org/T/#t
Would this be plausible?
---
arch/x86/kernel/cpu/sgx/main.c | 44 ++++++++++++++++++++++++----------
1 file changed, 31 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 0aad028f04d4..6d0e38078d28 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -43,8 +43,6 @@ static nodemask_t sgx_numa_mask;
*/
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
@@ -392,16 +390,23 @@ void sgx_reclaim_direct(void)
sgx_reclaim_pages();
}
-static int ksgxd(void *p)
+/*
+ * The page list head must be allocated from the heap, and its ownership is
+ * transferred to ksgxd, which takes care of destroying it.
+ */
+static int ksgxd(void *page_list_ptr)
{
+ struct list_head *page_list = page_list_ptr;
+
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));
+ __sgx_sanitize_pages(page_list);
+ WARN_ON(__sgx_sanitize_pages(page_list));
+ kfree(page_list);
while (!kthread_should_stop()) {
if (try_to_freeze())
@@ -420,11 +425,11 @@ static int ksgxd(void *p)
return 0;
}
-static bool __init sgx_page_reclaimer_init(void)
+static bool __init sgx_page_reclaimer_init(struct list_head *page_list)
{
struct task_struct *tsk;
- tsk = kthread_run(ksgxd, NULL, "ksgxd");
+ tsk = kthread_run(ksgxd, page_list, "ksgxd");
if (IS_ERR(tsk))
return false;
@@ -619,7 +624,8 @@ void sgx_free_epc_page(struct sgx_epc_page *page)
static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
unsigned long index,
- struct sgx_epc_section *section)
+ struct sgx_epc_section *section,
+ struct list_head *page_list)
{
unsigned long nr_pages = size >> PAGE_SHIFT;
unsigned long i;
@@ -643,7 +649,7 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size,
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);
+ list_add_tail(§ion->pages[i].list, page_list);
}
return true;
@@ -784,7 +790,7 @@ static void __init arch_update_sysfs_visibility(int nid)
static void __init arch_update_sysfs_visibility(int nid) {}
#endif
-static bool __init sgx_page_cache_init(void)
+static bool __init sgx_page_cache_init(struct list_head *page_list)
{
u32 eax, ebx, ecx, edx, type;
u64 pa, size;
@@ -812,7 +818,7 @@ static bool __init sgx_page_cache_init(void)
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])) {
+ if (!sgx_setup_epc_section(pa, size, i, &sgx_epc_sections[i], page_list)) {
pr_err("No free memory for an EPC section\n");
break;
}
@@ -912,20 +918,32 @@ EXPORT_SYMBOL_GPL(sgx_set_attribute);
static int __init sgx_init(void)
{
+ struct list_head *page_list;
int ret;
int i;
if (!cpu_feature_enabled(X86_FEATURE_SGX))
return -ENODEV;
- if (!sgx_page_cache_init())
+ page_list = kzalloc(sizeof(*page_list), GFP_KERNEL);
+ if (!page_list)
return -ENOMEM;
- if (!sgx_page_reclaimer_init()) {
+ INIT_LIST_HEAD(page_list);
+
+ if (!sgx_page_cache_init(page_list)) {
+ kfree(page_list);
+ return -ENOMEM;
+ }
+
+ if (!sgx_page_reclaimer_init(page_list)) {
+ kfree(page_list);
ret = -ENOMEM;
goto err_page_cache;
}
+ /* page_list is now owned by ksgxd. */
+
ret = misc_register(&sgx_dev_provision);
if (ret)
goto err_kthread;
--
2.37.2
next reply other threads:[~2022-09-06 3:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 3:12 Jarkko Sakkinen [this message]
2022-09-06 3:20 ` [PATCH RFC] x86/sgx: Use a heap allocated list head for unsanitized pages Dave Hansen
2022-09-06 3:52 ` Jarkko Sakkinen
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