[PATCH v3 03/28] x86/sgx: Add 'struct sgx_epc_lru_lists' to encapsulate lru list(s)

Haitao Huang
2023-07-12T23:02:46Z

From: Kristen Carlson Accardi <kristen@linux.intel.com>

Introduce a data structure to wrap the existing reclaimable list
and its spinlock in a struct to minimize the code changes needed
to handle multiple LRUs as well as reclaimable and non-reclaimable
lists. The new structure will be used in a following set of patches to
implement SGX EPC cgroups.

The changes to the structure needed for unreclaimable lists will be
added in later patches.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Haitao Huang <haitao.huang@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>

V3:
Removed the helper functions and revised commit messages
---
arch/x86/kernel/cpu/sgx/sgx.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h
index f6e3c5810eef..77fceba73a25 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -92,6 +92,23 @@ static inline void *sgx_get_epc_virt_addr(struct sgx_epc_page *page)
return section->virt_addr + index * PAGE_SIZE;
}

+/*
+ * This data structure wraps a list of reclaimable EPC pages, and a list of
+ * non-reclaimable EPC pages and is used to implement a LRU policy during
+ * reclamation.
+ */
+struct sgx_epc_lru_lists {
+ /* Must acquire this lock to access */
+ spinlock_t lock;
+ struct list_head reclaimable;
+};
+
+static inline void sgx_lru_init(struct sgx_epc_lru_lists *lrus)
+{
+ spin_lock_init(&lrus->lock);
+ INIT_LIST_HEAD(&lrus->reclaimable);
+}
+
struct sgx_epc_page *__sgx_alloc_epc_page(void);
void sgx_free_epc_page(struct sgx_epc_page *page);

--
2.25.1