[PATCH v5 04/18] x86/sgx: Use sgx_epc_lru_lists for existing active page list

[Haitao Huang]

From: Sean Christopherson <sean.j.christopher...@intel.com>

All EPC pages of enclaves including Version Array (VA) and SGX Enclave
Control Structure (SECS) will be tracked in sgx_epc_lru_lists structs,
one per cgroup. For now just replace the existing sgx_active_page_list
in the reclaimer and its spinlock with a global sgx_epc_lru_lists
struct. VA and SECS pages are still not tracked at this point but they
will be tracked after an unreclaimable LRU list is added to the
sgx_epc_lru_lists struct.

Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
Co-developed-by: Kristen Carlson Accardi <kris...@linux.intel.com>
Signed-off-by: Kristen Carlson Accardi <kris...@linux.intel.com>
Co-developed-by: Haitao Huang <haitao.hu...@linux.intel.com>
Signed-off-by: Haitao Huang <haitao.hu...@linux.intel.com>
Cc: Sean Christopherson <sea...@google.com>
---
V5:
- Spelled out SECS, VA (Jarkko)

V4:
- No change, only reordered the patch.

V3:
- Remove usage of list wrapper
---
 arch/x86/kernel/cpu/sgx/main.c | 39 +++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 166692f2d501..afce51d6e94a 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -26,10 +26,9 @@ 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.
+ * with sgx_global_lru.lock acquired.
  */
-static LIST_HEAD(sgx_active_page_list);
-static DEFINE_SPINLOCK(sgx_reclaimer_lock);
+static struct sgx_epc_lru_lists sgx_global_lru;
 
 static atomic_long_t sgx_nr_free_pages = ATOMIC_LONG_INIT(0);
 
@@ -304,13 +303,13 @@ static void sgx_reclaim_pages(void)
        int ret;
        int i;
 
-       spin_lock(&sgx_reclaimer_lock);
+       spin_lock(&sgx_global_lru.lock);
        for (i = 0; i < SGX_NR_TO_SCAN; i++) {
-               if (list_empty(&sgx_active_page_list))
+               epc_page = list_first_entry_or_null(&sgx_global_lru.reclaimable,
+                                                   struct sgx_epc_page, list);
+               if (!epc_page)
                        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;
 
@@ -322,7 +321,7 @@ static void sgx_reclaim_pages(void)
                         */
                        epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
        }
-       spin_unlock(&sgx_reclaimer_lock);
+       spin_unlock(&sgx_global_lru.lock);
 
        for (i = 0; i < cnt; i++) {
                epc_page = chunk[i];
@@ -345,9 +344,9 @@ static void sgx_reclaim_pages(void)
                continue;
 
 skip:
-               spin_lock(&sgx_reclaimer_lock);
-               list_add_tail(&epc_page->list, &sgx_active_page_list);
-               spin_unlock(&sgx_reclaimer_lock);
+               spin_lock(&sgx_global_lru.lock);
+               list_add_tail(&epc_page->list, &sgx_global_lru.reclaimable);
+               spin_unlock(&sgx_global_lru.lock);
 
                kref_put(&encl_page->encl->refcount, sgx_encl_release);
 
@@ -378,7 +377,7 @@ static void sgx_reclaim_pages(void)
 static bool sgx_should_reclaim(unsigned long watermark)
 {
        return atomic_long_read(&sgx_nr_free_pages) < watermark &&
-              !list_empty(&sgx_active_page_list);
+              !list_empty(&sgx_global_lru.reclaimable);
 }
 
 /*
@@ -430,6 +429,8 @@ static bool __init sgx_page_reclaimer_init(void)
 
        ksgxd_tsk = tsk;
 
+       sgx_lru_init(&sgx_global_lru);
+
        return true;
 }
 
@@ -505,10 +506,10 @@ struct sgx_epc_page *__sgx_alloc_epc_page(void)
  */
 void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
 {
-       spin_lock(&sgx_reclaimer_lock);
+       spin_lock(&sgx_global_lru.lock);
        page->flags |= SGX_EPC_PAGE_RECLAIMER_TRACKED;
-       list_add_tail(&page->list, &sgx_active_page_list);
-       spin_unlock(&sgx_reclaimer_lock);
+       list_add_tail(&page->list, &sgx_global_lru.reclaimable);
+       spin_unlock(&sgx_global_lru.lock);
 }
 
 /**
@@ -523,18 +524,18 @@ void sgx_mark_page_reclaimable(struct sgx_epc_page *page)
  */
 int sgx_unmark_page_reclaimable(struct sgx_epc_page *page)
 {
-       spin_lock(&sgx_reclaimer_lock);
+       spin_lock(&sgx_global_lru.lock);
        if (page->flags & SGX_EPC_PAGE_RECLAIMER_TRACKED) {
                /* The page is being reclaimed. */
                if (list_empty(&page->list)) {
-                       spin_unlock(&sgx_reclaimer_lock);
+                       spin_unlock(&sgx_global_lru.lock);
                        return -EBUSY;
                }
 
                list_del(&page->list);
                page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
        }
-       spin_unlock(&sgx_reclaimer_lock);
+       spin_unlock(&sgx_global_lru.lock);
 
        return 0;
 }
@@ -567,7 +568,7 @@ struct sgx_epc_page *sgx_alloc_epc_page(void *owner, bool 
reclaim)
                        break;
                }
 
-               if (list_empty(&sgx_active_page_list))
+               if (list_empty(&sgx_global_lru.reclaimable))
                        return ERR_PTR(-ENOMEM);
 
                if (!reclaim) {
-- 
2.25.1