Messages in this thread | | | Date | Mon, 5 Nov 2018 16:11:28 +0200 | From | Jarkko Sakkinen <> | Subject | Re: [PATCH v15 05/23] x86/cpu/intel: Detect SGX support and update caps appropriately |
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On Mon, Nov 05, 2018 at 04:09:33PM +0200, Jarkko Sakkinen wrote: > On Sat, Nov 03, 2018 at 03:05:39PM +0200, Andy Shevchenko wrote: > > > +static void detect_sgx(struct cpuinfo_x86 *c) > > > +{ > > > + bool unsupported = false; > > > + unsigned long long fc; > > > + > > > + rdmsrl(MSR_IA32_FEATURE_CONTROL, fc); > > > + if (!(fc & FEATURE_CONTROL_LOCKED)) { > > > + pr_err_once("sgx: IA32_FEATURE_CONTROL MSR is not locked\n"); > > > + unsupported = true; > > > + } else if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) { > > > + pr_err_once("sgx: not enabled in IA32_FEATURE_CONTROL MSR\n"); > > > + unsupported = true; > > > + } else if (!cpu_has(c, X86_FEATURE_SGX1)) { > > > + pr_err_once("sgx: SGX1 instruction set not supported\n"); > > > + unsupported = true; > > > + } > > > > If you do > > > > } else { > > /* Supported */ > > return; > > } > > Agree. Would this be a more clean flow in the attached patch?
Actually I'll paste the whole function for clarity because it is not too long:
static void detect_sgx(struct cpuinfo_x86 *c) { unsigned long long fc;
rdmsrl(MSR_IA32_FEATURE_CONTROL, fc); if (!(fc & FEATURE_CONTROL_LOCKED)) { pr_err_once("sgx: IA32_FEATURE_CONTROL MSR is not locked\n"); goto out_unsupported; }
if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) { pr_err_once("sgx: not enabled in IA32_FEATURE_CONTROL MSR\n"); goto out_unsupported; }
if (!cpu_has(c, X86_FEATURE_SGX1)) { pr_err_once("sgx: SGX1 instruction set not supported\n"); goto out_unsupported; }
if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) { pr_info_once("sgx: launch control MSRs are not writable\n"); goto out_msrs_rdonly; }
return; out_unsupported: setup_clear_cpu_cap(X86_FEATURE_SGX); setup_clear_cpu_cap(X86_FEATURE_SGX1); setup_clear_cpu_cap(X86_FEATURE_SGX2); out_msrs_rdonly: setup_clear_cpu_cap(X86_FEATURE_SGX_LC); }
/Jarkko
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