On Wed, May 11, 2022 at 11:01:50AM -0700, Reinette Chatre wrote:
> Hi Jarkko,
>
> On 5/11/2022 3:43 AM, Jarkko Sakkinen wrote:
> > 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@xxxxxxxxx>
> >> ---
> >> 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@xxxxxxxxxx>
>
> Thank you very much.
>
> Based on my understanding of Dave's feedback I do plan to move the
> set_page_dirty() to be after the memset:
> https://lore.kernel.org/linux-sgx/8922e48f-6646-c7cc-6393-7c78dcf23d23@xxxxxxxxx/
>
> Reinette
You can keep my tag, I'll compare the patches and complain if there was
anything else done :-) Do not expect that though (at all).
BR, Jarkko
