Re: [RFC PATCH v2 04/26] x86/sgx: Add SGX_CHILD_PRESENT hardware error code

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Jan 18, 2021 at 04:26:52PM +1300, Kai Huang wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> SGX virtualization requires to allocate "raw" EPC and use it as "virtual
> EPC" for SGX guest.  Unlike EPC used by SGX driver, virtual EPC doesn't
> track how EPC pages are used in VM, e.g. (de)construction of enclaves,
> so it cannot guarantee EREMOVE success, e.g. it doesn't have a priori
> knowledge of which pages are SECS with non-zero child counts.
> 
> Add SGX_CHILD_PRESENT for use by SGX virtualization to assert EREMOVE
> failures are expected, but only due to SGX_CHILD_PRESENT.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Kai Huang <kai.huang@intel.com>
> ---
> v1->v2:
> 
>  - Change title to reflect hardware error code.
> 
> ---
>  arch/x86/kernel/cpu/sgx/arch.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/arch.h b/arch/x86/kernel/cpu/sgx/arch.h
> index dd7602c44c72..56b0f8ae3f92 100644
> --- a/arch/x86/kernel/cpu/sgx/arch.h
> +++ b/arch/x86/kernel/cpu/sgx/arch.h
> @@ -26,12 +26,14 @@
>   * enum sgx_return_code - The return code type for ENCLS, ENCLU and ENCLV
>   * %SGX_NOT_TRACKED:		Previous ETRACK's shootdown sequence has not
>   *				been completed yet.
> + * %SGX_CHILD_PRESENT		Enclave has child pages present in the EPC.

s/Enclave/SECS/

>   * %SGX_INVALID_EINITTOKEN:	EINITTOKEN is invalid and enclave signer's
>   *				public key does not match IA32_SGXLEPUBKEYHASH.
>   * %SGX_UNMASKED_EVENT:		An unmasked event, e.g. INTR, was received
>   */
>  enum sgx_return_code {
>  	SGX_NOT_TRACKED			= 11,
> +	SGX_CHILD_PRESENT		= 13,
>  	SGX_INVALID_EINITTOKEN		= 16,
>  	SGX_UNMASKED_EVENT		= 128,
>  };
> -- 
> 2.29.2
> 
> 

/Jarkko