The following commit has been merged into the x86/sgx branch of tip:
Commit-ID: ee56a283988d739c25d2d00ffb22707cb487ab47
Gitweb: https://git.kernel.org/tip/ee56a283988d739c25d2d00ffb22707cb487ab47
Author: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
AuthorDate: Fri, 12 Aug 2022 11:18:03 -07:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 15 Aug 2022 11:51:49 +02:00
x86/sgx: Improve comments for sgx_encl_lookup/alloc_backing()
Modify the comments for sgx_encl_lookup_backing() and for
sgx_encl_alloc_backing() to indicate that they take a reference
which must be dropped with a call to sgx_encl_put_backing().
Make sgx_encl_lookup_backing() static for now, and change the
name of sgx_encl_get_backing() to __sgx_encl_get_backing() to
make it more clear that sgx_encl_get_backing() is an internal
function.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lore.kernel.org/all/YtUs3MKLzFg+rqEV@xxxxxxx/
---
arch/x86/kernel/cpu/sgx/encl.c | 21 ++++++++++++++-------
arch/x86/kernel/cpu/sgx/encl.h | 2 --
2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 24c1bb8..f40d642 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -12,6 +12,9 @@
#include "encls.h"
#include "sgx.h"
+static int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_index,
+ struct sgx_backing *backing);
+
#define PCMDS_PER_PAGE (PAGE_SIZE / sizeof(struct sgx_pcmd))
/*
* 32 PCMD entries share a PCMD page. PCMD_FIRST_MASK is used to
@@ -914,7 +917,7 @@ static struct page *sgx_encl_get_backing_page(struct sgx_encl *encl,
}
/**
- * sgx_encl_get_backing() - Pin the backing storage
+ * __sgx_encl_get_backing() - Pin the backing storage
* @encl: an enclave pointer
* @page_index: enclave page index
* @backing: data for accessing backing storage for the page
@@ -926,7 +929,7 @@ static struct page *sgx_encl_get_backing_page(struct sgx_encl *encl,
* 0 on success,
* -errno otherwise.
*/
-static int sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
+static int __sgx_encl_get_backing(struct sgx_encl *encl, unsigned long page_index,
struct sgx_backing *backing)
{
pgoff_t page_pcmd_off = sgx_encl_get_backing_page_pcmd_offset(encl, page_index);
@@ -1001,7 +1004,7 @@ static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl)
}
/**
- * sgx_encl_alloc_backing() - allocate a new backing storage page
+ * sgx_encl_alloc_backing() - create a new backing storage page
* @encl: an enclave pointer
* @page_index: enclave page index
* @backing: data for accessing backing storage for the page
@@ -1009,7 +1012,9 @@ static struct mem_cgroup *sgx_encl_get_mem_cgroup(struct sgx_encl *encl)
* When called from ksgxd, sets the active memcg from one of the
* mms in the enclave's mm_list prior to any backing page allocation,
* in order to ensure that shmem page allocations are charged to the
- * enclave.
+ * enclave. Create a backing page for loading data back into an EPC page with
+ * ELDU. This function takes a reference on a new backing page which
+ * must be dropped with a corresponding call to sgx_encl_put_backing().
*
* Return:
* 0 on success,
@@ -1022,7 +1027,7 @@ int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index,
struct mem_cgroup *memcg = set_active_memcg(encl_memcg);
int ret;
- ret = sgx_encl_get_backing(encl, page_index, backing);
+ ret = __sgx_encl_get_backing(encl, page_index, backing);
set_active_memcg(memcg);
mem_cgroup_put(encl_memcg);
@@ -1040,15 +1045,17 @@ int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index,
* It is the caller's responsibility to ensure that it is appropriate to use
* sgx_encl_lookup_backing() rather than sgx_encl_alloc_backing(). If lookup is
* not used correctly, this will cause an allocation which is not accounted for.
+ * This function takes a reference on an existing backing page which must be
+ * dropped with a corresponding call to sgx_encl_put_backing().
*
* Return:
* 0 on success,
* -errno otherwise.
*/
-int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_index,
+static int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_index,
struct sgx_backing *backing)
{
- return sgx_encl_get_backing(encl, page_index, backing);
+ return __sgx_encl_get_backing(encl, page_index, backing);
}
/**
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index a65a952..f94ff14 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -107,8 +107,6 @@ bool current_is_ksgxd(void);
void sgx_encl_release(struct kref *ref);
int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm);
const cpumask_t *sgx_encl_cpumask(struct sgx_encl *encl);
-int sgx_encl_lookup_backing(struct sgx_encl *encl, unsigned long page_index,
- struct sgx_backing *backing);
int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index,
struct sgx_backing *backing);
void sgx_encl_put_backing(struct sgx_backing *backing);
|