linux-kernel - Re: [PATCH 3/5] selftests/sgx: Ensure correct secinfo struct alignment in test enclave.

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Date:   Fri, 28 Jul 2023 19:05:51 +0000
From:   "Jarkko Sakkinen" <jarkko@...nel.org>
To:     "Jo Van Bulck" <jo.vanbulck@...kuleuven.be>,
        <linux-sgx@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Cc:     <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH 3/5] selftests/sgx: Ensure correct secinfo struct
 alignment in test enclave.

On Mon Jul 24, 2023 at 4:58 PM UTC, Jo Van Bulck wrote:
> Declare the secinfo struct as volatile to prevent compiler optimizations
> from passing an unaligned pointer to ENCLU.
>
> Signed-off-by: Jo Van Bulck <jo.vanbulck@...kuleuven.be>
> ---
>  tools/testing/selftests/sgx/test_encl.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c
> index 4e31a6c3d673..aba301abefb8 100644
> --- a/tools/testing/selftests/sgx/test_encl.c
> +++ b/tools/testing/selftests/sgx/test_encl.c
> @@ -18,7 +18,8 @@ enum sgx_enclu_function {
>  
>  static void do_encl_emodpe(void *_op)
>  {
> -	struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
> +	/* declare secinfo volatile to preserve alignment */
> +	volatile struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
>  	struct encl_op_emodpe *op = _op;
>  
>  	secinfo.flags = op->flags;
> @@ -32,7 +33,8 @@ static void do_encl_emodpe(void *_op)
>  
>  static void do_encl_eaccept(void *_op)
>  {
> -	struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
> +	/* declare secinfo volatile to preserve alignment */
> +	volatile struct sgx_secinfo secinfo __aligned(sizeof(struct sgx_secinfo)) = {0};
>  	struct encl_op_eaccept *op = _op;
>  	int rax;
>  
> -- 
> 2.34.1

Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>

BR, Jarkko