linux-kernel - [PATCH 1/3] x86/sgx: Move struct sgx_va_page creation to sgx_alloc_va

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Date:   Thu, 25 Feb 2021 00:20:47 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     linux-sgx@...r.kernel.org
Cc:     haitao.huang@...el.com, dan.j.williams@...el.com,
        dave.hansen@...ux.intel.com, bp@...en8.de, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, x86@...nel.org,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 1/3] x86/sgx: Move struct sgx_va_page creation to sgx_alloc_va_page()

The VA page creation is illogically split in-between sgx_encl_grow() and
sgx_alloc_va_page(). Move it fully to sgx_alloc_va_page().

Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
---
 arch/x86/kernel/cpu/sgx/encl.c  | 36 +++++++++++++++++++++++----------
 arch/x86/kernel/cpu/sgx/encl.h  |  2 +-
 arch/x86/kernel/cpu/sgx/ioctl.c | 20 ++++--------------
 3 files changed, 30 insertions(+), 28 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 7449ef33f081..42eb879c167a 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -671,26 +671,40 @@ int sgx_encl_test_and_clear_young(struct mm_struct *mm,
  * Allocate a free EPC page and convert it to a Version Array (VA) page.
  *
  * Return:
- *   a VA page,
- *   -errno otherwise
+ * - A VA page:		On success.
+ * - ERR_PTR(-errno):	Otherwise.
  */
-struct sgx_epc_page *sgx_alloc_va_page(void)
+struct sgx_va_page *sgx_alloc_va_page(void)
 {
-	struct sgx_epc_page *epc_page;
+	struct sgx_va_page *va_page;
 	int ret;
 
-	epc_page = sgx_alloc_epc_page(NULL, true);
-	if (IS_ERR(epc_page))
-		return ERR_CAST(epc_page);
+	va_page = kzalloc(sizeof(*va_page), GFP_KERNEL);
+	if (!va_page)
+		return ERR_PTR(-ENOMEM);
 
-	ret = __epa(sgx_get_epc_virt_addr(epc_page));
+	va_page->epc_page = sgx_alloc_epc_page(NULL, true);
+	if (IS_ERR(va_page->epc_page)) {
+		ret = PTR_ERR(va_page->epc_page);
+		goto err_va_page;
+	}
+
+	ret = __epa(sgx_get_epc_virt_addr(va_page->epc_page));
 	if (ret) {
 		WARN_ONCE(1, "EPA returned %d (0x%x)", ret, ret);
-		sgx_free_epc_page(epc_page);
-		return ERR_PTR(-EFAULT);
+		ret = -EFAULT;
+		goto err_epc_page;
 	}
 
-	return epc_page;
+	return va_page;
+
+err_epc_page:
+	sgx_free_epc_page(va_page->epc_page);
+
+err_va_page:
+	kfree(va_page);
+
+	return ERR_PTR(ret);
 }
 
 /**
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index d8d30ccbef4c..315e87fcc142 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -111,7 +111,7 @@ void sgx_encl_put_backing(struct sgx_backing *backing, bool do_write);
 int sgx_encl_test_and_clear_young(struct mm_struct *mm,
 				  struct sgx_encl_page *page);
 
-struct sgx_epc_page *sgx_alloc_va_page(void);
+struct sgx_va_page *sgx_alloc_va_page(void);
 unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page);
 void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset);
 bool sgx_va_page_full(struct sgx_va_page *va_page);
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index 90a5caf76939..db6e2c6ad42d 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -19,26 +19,14 @@
 static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
 {
 	struct sgx_va_page *va_page = NULL;
-	void *err;
 
-	BUILD_BUG_ON(SGX_VA_SLOT_COUNT !=
-		(SGX_ENCL_PAGE_VA_OFFSET_MASK >> 3) + 1);
+	BUILD_BUG_ON(SGX_VA_SLOT_COUNT != (SGX_ENCL_PAGE_VA_OFFSET_MASK >> 3) + 1);
 
-	if (!(encl->page_cnt % SGX_VA_SLOT_COUNT)) {
-		va_page = kzalloc(sizeof(*va_page), GFP_KERNEL);
-		if (!va_page)
-			return ERR_PTR(-ENOMEM);
+	if (!(encl->page_cnt % SGX_VA_SLOT_COUNT))
+		va_page = sgx_alloc_va_page();
 
-		va_page->epc_page = sgx_alloc_va_page();
-		if (IS_ERR(va_page->epc_page)) {
-			err = ERR_CAST(va_page->epc_page);
-			kfree(va_page);
-			return err;
-		}
-
-		WARN_ON_ONCE(encl->page_cnt % SGX_VA_SLOT_COUNT);
-	}
 	encl->page_cnt++;
+
 	return va_page;
 }
 
-- 
2.30.1