A kernel requires X86_FEATURE_SGX_LC to be able to create SGX enclaves. There is quite a number of hardware which has X86_FEATURE_SGX but not X86_FEATURE_SGX_LC. A kernel running on such a hardware does not create /dev/sgx_enclave file silently. Explicitly warn if X86_FEATURE_SGX_LC is not enabled to properly nofity a user about this condition. The X86_FEATURE_SGX_LC is a CPU feature that enables LE hash MSRs to be writable when running native enclaves, i.e. using a custom root key rather than the Intel proprietary key for enclave signing. Signed-off-by: Vladis Dronov <vdronov@xxxxxxxxxx> --- an out-of-commit-message note: I've hit this issue myself and have spent some time researching where is my /dev/sgx_enclave file on an SGX-enabled hardware, so this is a bit personal. Links related: https://github.com/intel/linux-sgx/issues/837 https://patchwork.kernel.org/project/platform-driver-x86/patch/20180827185507.17087-3-jarkko.sakkinen@xxxxxxxxxxxxxxx/ arch/x86/kernel/cpu/sgx/driver.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c index 22b65a5f5ec6..df4fbfaa6616 100644 --- a/arch/x86/kernel/cpu/sgx/driver.c +++ b/arch/x86/kernel/cpu/sgx/driver.c @@ -150,8 +150,10 @@ int __init sgx_drv_init(void) u64 xfrm_mask; int ret; - if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) + if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) { + pr_err("SGX disabled: SGX launch control is not available.\n"); return -ENODEV; + } cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx); -- 2.48.1
