From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: linux-kernel@vger.kernel.org, Jarkko Sakkinen <jarkko@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: Kristen Carlson Accardi <kristen.c.accardi@intel.com>,
linux-sgx@vger.kernel.org
Subject: [PATCH v2] x86/sgx: Improve comments for sgx_encl_lookup/alloc_backing()
Date: Fri, 12 Aug 2022 11:18:03 -0700 [thread overview]
Message-ID: <20220812181803.567931-1-kristen@linux.intel.com> (raw)
From: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
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.
Link: https://lore.kernel.org/all/YtUs3MKLzFg+rqEV@zn.tnic/
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
---
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 19876ebfb504..325c2d59e6b4 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
@@ -706,7 +709,7 @@ 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
@@ -718,7 +721,7 @@ 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);
@@ -794,7 +797,7 @@ 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
@@ -802,7 +805,9 @@ 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,
@@ -815,7 +820,7 @@ 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);
@@ -833,15 +838,17 @@ 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 332ef3568267..d731ef53f815 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -106,8 +106,6 @@ int sgx_encl_may_map(struct sgx_encl *encl, unsigned long start,
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);
-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);
--
2.36.1
reply other threads:[~2022-08-12 18:18 UTC|newest]
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