Re: [RFC PATCH v3 03/10] x86/sgx: Save enclave pointer for VA page

Jarkko Sakkinen
2022-04-03T10:07:16Z

On Fri, Apr 01, 2022 at 10:24:02PM +0800, Cathy Zhang wrote:
> Tearing down all enclaves is required by SGX SVN update, which
> involves running the ENCLS[EREMOVE] instruction on every EPC
> page. This (tearing down all enclaves) should be coordinated
> with any enclaves that may be in the process of existing and thus
> already be running ENCLS[EREMOVE] as part of enclave release.
>
> In support of this coordination, it is required to know which enclave
> owns each in-use EPC page. It is already possible to locate the
> owning enclave of SECS and regular pages but not for VA pages.
>
> Save the enclave pointer for each VA page to support locating its
> owning enclave.
>
> Note: to track 2T EPC memory, this scheme of tracking will use
> additional 8M memory.
>
> Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
> ---
> arch/x86/kernel/cpu/sgx/encl.h | 1 +
> arch/x86/kernel/cpu/sgx/ioctl.c | 1 +
> 2 files changed, 2 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
> index 0c8571fc30cf..59fbd4ed5c64 100644
> --- a/arch/x86/kernel/cpu/sgx/encl.h
> +++ b/arch/x86/kernel/cpu/sgx/encl.h
> @@ -76,6 +76,7 @@ struct sgx_va_page {
> struct sgx_epc_page *epc_page;
> DECLARE_BITMAP(slots, SGX_VA_SLOT_COUNT);
> struct list_head list;
> + struct sgx_encl *encl;
> };
>
> struct sgx_backing {
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index f0ce96bd462a..da82abbb81b4 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -30,6 +30,7 @@ static struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl)
> if (!va_page)
> return ERR_PTR(-ENOMEM);
>
> + va_page->encl = encl;
> va_page->epc_page = sgx_alloc_va_page(va_page);
> if (IS_ERR(va_page->epc_page)) {
> err = ERR_CAST(va_page->epc_page);
> --
> 2.17.1
>

Squash this with the previous patch. Then the code will provide
answer to one of the questions that I mentioned in 2/10 review.

BR, Jarkko