[PATCHv7,13/14] x86/tdx: Refactor try_accept_one()

Commit Message

Kirill A. Shutemov June 14, 2022, 12:02 p.m. UTC

Rework try_accept_one() to return accepted size instead of modifying
'start' inside the helper. It makes 'start' in-only argumaent and
streamlines code on the caller side.

Signed-off-by: Kirill A. Shutemov <[e-mail]>
Suggested-by: Borislav Petkov <[e-mail]>
---
 arch/x86/coco/tdx/tdx.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

Comments

Dave Hansen June 23, 2022, 5:31 p.m. UTC | #1

On 6/14/22 05:02, Kirill A. Shutemov wrote:
> Rework try_accept_one() to return accepted size instead of modifying
> 'start' inside the helper. It makes 'start' in-only argumaent and

							^ argument

> streamlines code on the caller side.
> 
> Signed-off-by: Kirill A. Shutemov <[e-mail]>
> Suggested-by: Borislav Petkov <[e-mail]>

I'm not sure how much it actually streamlines things.  The line count
looks pretty similar.  But, I do generally dislike implicit return
values, so with that typo fixed:

Reviewed-by: Dave Hansen <[e-mail]>

Borislav Petkov July 26, 2022, 10:58 a.m. UTC | #2

On Tue, Jun 14, 2022 at 03:02:30PM +0300, Kirill A. Shutemov wrote:
> Rework try_accept_one() to return accepted size instead of modifying
> 'start' inside the helper. It makes 'start' in-only argumaent and

Unknown word [argumaent] in commit message.
Suggestions: ['argument', 'augment', 'arguments', 'armament', 'argent', "argument's"]

You need a spellchecker enabled in your editor with which you write your
commit messages.

Thx.

Patch

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c
index b75fe670032b..b10c95307f6e 100644
--- a/arch/x86/coco/tdx/tdx.c
+++ b/arch/x86/coco/tdx/tdx.c
@@ -624,18 +624,18 @@  static bool tdx_cache_flush_required(void)
 	return true;
 }
 
-static bool try_accept_one(phys_addr_t *start, unsigned long len,
-			  enum pg_level pg_level)
+static unsigned long try_accept_one(phys_addr_t start, unsigned long len,
+				    enum pg_level pg_level)
 {
 	unsigned long accept_size = page_level_size(pg_level);
 	u64 tdcall_rcx;
 	u8 page_size;
 
-	if (!IS_ALIGNED(*start, accept_size))
-		return false;
+	if (!IS_ALIGNED(start, accept_size))
+		return 0;
 
 	if (len < accept_size)
-		return false;
+		return 0;
 
 	/*
 	 * Pass the page physical address to the TDX module to accept the
@@ -654,15 +654,14 @@  static bool try_accept_one(phys_addr_t *start, unsigned long len,
 		page_size = 2;
 		break;
 	default:
-		return false;
+		return 0;
 	}
 
-	tdcall_rcx = *start | page_size;
+	tdcall_rcx = start | page_size;
 	if (__tdx_module_call(TDX_ACCEPT_PAGE, tdcall_rcx, 0, 0, 0, NULL))
-		return false;
+		return 0;
 
-	*start += accept_size;
-	return true;
+	return accept_size;
 }
 
 /*
@@ -699,21 +698,22 @@  static bool tdx_enc_status_changed(unsigned long vaddr, int numpages, bool enc)
 	 */
 	while (start < end) {
 		unsigned long len = end - start;
+		unsigned long accept_size;
 
 		/*
 		 * Try larger accepts first. It gives chance to VMM to keep
-		 * 1G/2M SEPT entries where possible and speeds up process by
-		 * cutting number of hypercalls (if successful).
+		 * 1G/2M Secure EPT entries where possible and speeds up
+		 * process by cutting number of hypercalls (if successful).
 		 */
 
-		if (try_accept_one(&start, len, PG_LEVEL_1G))
-			continue;
-
-		if (try_accept_one(&start, len, PG_LEVEL_2M))
-			continue;
-
-		if (!try_accept_one(&start, len, PG_LEVEL_4K))
+		accept_size = try_accept_one(start, len, PG_LEVEL_1G);
+		if (!accept_size)
+			accept_size = try_accept_one(start, len, PG_LEVEL_2M);
+		if (!accept_size)
+			accept_size = try_accept_one(start, len, PG_LEVEL_4K);
+		if (!accept_size)
 			return false;
+		start += accept_size;
 	}
 
 	return true;