| Message ID | 217608112793e76b335540edde75dfda290de16c.1652131695.git.reinette.chatre@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V2,1/5] x86/sgx: Disconnect backing page references from dirty status | expand |
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
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@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> 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@intel.com/ Reinette
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@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> > > 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@intel.com/ > > 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
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)); /*
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(+)