[intel-sgx-kernel-dev,RFC,05/12] intel_sgx: add struct sgx_epc_lru to encapsulate lru list(s)

Commit Message

Sean Christopherson June 14, 2017, 5:37 p.m. UTC

Signed-off-by: Sean Christopherson <[e-mail]>
---
 drivers/platform/x86/intel_sgx/sgx.h            | 11 ++++++
 drivers/platform/x86/intel_sgx/sgx_page_cache.c | 46 ++++++++++++++++---------
 2 files changed, 41 insertions(+), 16 deletions(-)

Patch

diff --git a/drivers/platform/x86/intel_sgx/sgx.h b/drivers/platform/x86/intel_sgx/sgx.h
index eba67ce..98c75fb 100644
--- a/drivers/platform/x86/intel_sgx/sgx.h
+++ b/drivers/platform/x86/intel_sgx/sgx.h
@@ -147,6 +147,17 @@  struct sgx_epc_bank {
 	unsigned long end;
 };
 
+struct sgx_epc_lru {
+	spinlock_t lock;
+	struct list_head active_lru;
+};
+
+static inline void sgx_lru_init(struct sgx_epc_lru *lru)
+{
+	spin_lock_init(&lru->lock);
+	INIT_LIST_HEAD(&lru->active_lru);
+}
+
 extern struct workqueue_struct *sgx_add_page_wq;
 extern struct sgx_epc_bank sgx_epc_banks[];
 extern int sgx_nr_epc_banks;
diff --git a/drivers/platform/x86/intel_sgx/sgx_page_cache.c b/drivers/platform/x86/intel_sgx/sgx_page_cache.c
index 9976205..9a1981c 100644
--- a/drivers/platform/x86/intel_sgx/sgx_page_cache.c
+++ b/drivers/platform/x86/intel_sgx/sgx_page_cache.c
@@ -71,8 +71,7 @@ 
 
 static LIST_HEAD(sgx_free_list);
 static DEFINE_SPINLOCK(sgx_free_list_lock);
-static LIST_HEAD(sgx_active_list);
-static DEFINE_SPINLOCK(sgx_active_list_lock);
+static struct sgx_epc_lru sgx_global_lru;
 
 LIST_HEAD(sgx_encl_list);
 DEFINE_MUTEX(sgx_encl_mutex);
@@ -123,21 +122,25 @@  void sgx_activate_page(struct sgx_epc_page *epc_page,
 		       struct sgx_encl *encl,
 		       struct sgx_encl_page *encl_page)
 {
+	struct sgx_epc_lru *lru = &sgx_global_lru;
+
 	epc_page->encl = encl;
 	epc_page->encl_page = encl_page;
 
 	sgx_test_and_clear_young(encl_page, encl);
 
-	spin_lock(&sgx_active_list_lock);
-	list_add_tail(&epc_page->list, &sgx_active_list);
-	spin_unlock(&sgx_active_list_lock);
+	spin_lock(&lru->lock);
+	list_add_tail(&epc_page->list, &lru->active_lru);
+	spin_unlock(&lru->lock);
 }
 
 void sgx_deactivate_page(struct sgx_epc_page *epc_page)
 {
-	spin_lock(&sgx_active_list_lock);
+	struct sgx_epc_lru *lru = &sgx_global_lru;
+
+	spin_lock(&lru->lock);
 	list_del_init(&epc_page->list);
-	spin_unlock(&sgx_active_list_lock);
+	spin_unlock(&lru->lock);
 }
 
 static void sgx_isolate_pages(struct list_head *dst,
@@ -145,14 +148,15 @@  static void sgx_isolate_pages(struct list_head *dst,
 {
 	unsigned long i;
 	struct sgx_epc_page *entry;
+	struct sgx_epc_lru *lru = &sgx_global_lru;
 
-	spin_lock(&sgx_active_list_lock);
+	spin_lock(&lru->lock);
 
 	for (i = 0; i < nr_to_scan; i++) {
-		if (list_empty(&sgx_active_list))
+		if (list_empty(&lru->active_lru))
 			break;
 
-		entry = list_first_entry(&sgx_active_list,
+		entry = list_first_entry(&lru->active_lru,
 					 struct sgx_epc_page,
 					 list);
 
@@ -163,7 +167,7 @@  static void sgx_isolate_pages(struct list_head *dst,
 			list_move_tail(&entry->list, dst);
 	}
 
-	spin_unlock(&sgx_active_list_lock);
+	spin_unlock(&lru->lock);
 }
 
 static int __sgx_ewb(struct sgx_encl *encl,
@@ -320,6 +324,18 @@  static inline void sgx_del_if_dead(struct sgx_encl *encl,
 	}
 }
 
+static inline void sgx_lru_putback(struct list_head *src)
+{
+	struct sgx_epc_lru *lru = &sgx_global_lru;
+
+	if (list_empty(src))
+		return;
+
+	spin_lock(&lru->lock);
+	list_splice_tail_init(src, &lru->active_lru);
+	spin_unlock(&lru->lock);
+}
+
 static void sgx_swap_pages(unsigned long nr_to_scan)
 {
 	struct sgx_epc_page *entry, *tmp;
@@ -360,11 +376,7 @@  static void sgx_swap_pages(unsigned long nr_to_scan)
 
 		up_read(&encl->mm->mmap_sem);
 
-		if (!list_empty(&skip)) {
-			spin_lock(&sgx_active_list_lock);
-			list_splice_tail_init(&skip, &sgx_active_list);
-			spin_unlock(&sgx_active_list_lock);
-		}
+		sgx_lru_putback(&skip);
 
 		kref_put(&encl->refcount, sgx_encl_release);
 	}
@@ -418,6 +430,8 @@  int sgx_add_epc_bank(resource_size_t start, unsigned long size)
 
 int sgx_page_cache_init(void)
 {
+	sgx_lru_init(&sgx_global_lru);
+
 	sgx_nr_high_pages = 2 * sgx_nr_low_pages;
 	ksgxswapd_tsk = kthread_run(ksgxswapd, NULL, "ksgxswapd");
 	return PTR_ERR_OR_ZERO(ksgxswapd_tsk);