Messages in this thread | | | Subject | Re: [PATCH v13 06/13] x86/sgx: Detect Intel SGX | From | Dave Hansen <> | Date | Mon, 27 Aug 2018 12:53:59 -0700 |
| |
> +config INTEL_SGX_CORE > + prompt "Intel SGX core functionality" > + def_bool n > + depends on X86_64 && CPU_SUP_INTEL > + help > + Intel Software Guard eXtensions (SGX) is a set of CPU instructions > + that allows ring 3 applications to create enclaves, private regions > + of memory that are protected, by hardware, from unauthorized access > + and/or modification.
This is a bit comma-crazy. Also, considering some of our recent CVE fun, I'd probably not claim hardware protection. :)
Maybe:
Intel Software Guard eXtensions (SGX) CPU feature that allows ring 3 applications to create enclaves: private regions of memory that are architecturally protected from unauthorized access and/or modification.
> + This option enables kernel recognition of SGX, high-level management > + of the Enclave Page Cache (EPC), tracking and writing of SGX Launch > + Enclave Hash MSRs, and allows for virtualization of SGX via KVM. By > + iteslf, this option does not provide SGX support to userspace.
itself
> diff --git a/arch/x86/include/asm/sgx_pr.h b/arch/x86/include/asm/sgx_pr.h > new file mode 100644 > index 000000000000..c68578127620 > --- /dev/null > +++ b/arch/x86/include/asm/sgx_pr.h > @@ -0,0 +1,13 @@ > +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) > +// Copyright(c) 2016-17 Intel Corporation. > + > +#ifndef _ASM_X86_SGX_PR_H > +#define _ASM_X86_SGX_PR_H > + > +#include <linux/printk.h> > +#include <linux/ratelimit.h> > + > +#undef pr_fmt > +#define pr_fmt(fmt) "sgx: " fmt > + > +#endif /* _ASM_X86_SGX_PR_H */
I don't think this belongs in a generic header. Generally, we do the pr_fmt stuff in .c files, not in headers. If someone includes this header directly or indirectly, they'll get a big surprise.
If you *must* have this in a .h file, put it in arch/x86/kernel/cpu/intel_sgx.h or something and #include "intel_sgx.h" in all the .c files where you want this.
> +static __init int sgx_init(void) > +{ > + unsigned long fc; > + > + if (!boot_cpu_has(X86_FEATURE_SGX)) > + return false; > + > + if (!boot_cpu_has(X86_FEATURE_SGX1)) > + return false; > + > + rdmsrl(MSR_IA32_FEATURE_CONTROL, fc); > + if (!(fc & FEATURE_CONTROL_LOCKED)) { > + pr_info("IA32_FEATURE_CONTROL MSR is not locked\n"); > + return false; > + }
This is a rather crummy error message. Doesn't this keep sgx from initializing? Would something like this be more informative?
pr_info("failed init: IA32_FEATURE_CONTROL MSR not locked\n");
> + if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) { > + pr_info("disabled by the firmware\n"); > + return false; > + } > + > + if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) > + pr_info("IA32_SGXLEPUBKEYHASHn MSRs are not writable\n");
How about something that might help an end user? Perhaps:
pr_warn("launch configuration not available\n");
> + sgx_enabled = true; > + sgx_lc_enabled = !!(fc & FEATURE_CONTROL_SGX_LE_WR); > + return 0; > +} > + > +arch_initcall(sgx_init); >
| |