Re: Testing 5.17 bugfix material

["Accardi, Kristen C" <kristen.c.accardi@intel.com>]

On Fri, 2022-01-21 at 11:57 -0800, Dave Hansen wrote:
> Hi Everyone,
> 
> There are a few SGX fixes that have showed up in the last week or so,
> mostly around RAS and fixing the backing storage issues.  Could folks
> please give this branch a good thrashing?
> 
> > https://git.kernel.org/pub/scm/linux/kernel/git/daveh/devel.git/log/?h=x86/sgx
> 
> I'm planning to send this bunch up to Linus after 5.17-rc1 comes out.
> 
> Kristen, I really dug into the changelogs of your two patches to make
> it
> more clear that they are bugfix and stable@ material.  I'd appreciate
> some additional eyeballs there.

There's a bug in the calculation for the available backing bytes,
pointed out by Haitao and team. Here's a fix applied to your tree.

From 2ebcf0e70b1235224410e08c983e357d5ac3c435 Mon Sep 17 00:00:00 2001
From: Kristen Carlson Accardi <kristen@linux.intel.com>
Date: Mon, 24 Jan 2022 09:28:56 -0800
Subject: [PATCH] x86/sgx: fixup for available backing pages calculation

Remove improper parentheses from calculation for available backing
bytes. Without this fix, the result will be incorrect due to
rounding.

Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
---
 arch/x86/kernel/cpu/sgx/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 7ed6a1b10c21..10a6af89bf64 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -922,7 +922,7 @@ static bool __init sgx_page_cache_init(void)
 		return false;
 	}
 
-	available_backing_bytes = total_epc_bytes * (sgx_overcommit_percent / 100);
+	available_backing_bytes = total_epc_bytes * sgx_overcommit_percent / 100;
 	atomic_long_set(&sgx_nr_available_backing_pages, available_backing_bytes >> PAGE_SHIFT);
 
 	return true;
-- 
2.20.1