Re: [PATCH V2 2/5] x86/sgx: Mark PCMD page as dirty when modifying contents

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, May 09, 2022 at 02:48:00PM -0700, Reinette Chatre wrote:
> Recent commit 08999b2489b4 ("x86/sgx: Free backing memory
> after faulting the enclave page") expanded __sgx_encl_eldu()
> to clear an enclave page's PCMD (Paging Crypto MetaData)
> from the PCMD page in the backing store after the enclave
> page is restored to the enclave.
> 
> Since the PCMD page in the backing store is modified the page
> should be marked as dirty to ensure the modified data is retained.
> 
> Fixes: 08999b2489b4 ("x86/sgx: Free backing memory after faulting the enclave page")
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
> ---
> Changes since RFC v1:
> - Do not set dirty bit on enclave page since it is not being
>   written to and always will be discarded.  (Dave)
> 
>  arch/x86/kernel/cpu/sgx/encl.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
> index 398695a20605..2521d64e8bcf 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.c
> +++ b/arch/x86/kernel/cpu/sgx/encl.c
> @@ -83,6 +83,7 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page,
>  		ret = -EFAULT;
>  	}
>  
> +	set_page_dirty(b.pcmd);
>  	memset(pcmd_page + b.pcmd_offset, 0, sizeof(struct sgx_pcmd));
>  
>  	/*
> -- 
> 2.25.1
> 

LGTM.

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

BR, Jarkko