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SubjectRe: [PATCH v15 05/23] x86/cpu/intel: Detect SGX support and update caps appropriately
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:

> Agree. Would this be a more clean flow in the attached patch?

LGTM.

> From 3b863a7db00cefffc15df918a5132c35ea313c27 Mon Sep 17 00:00:00 2001
> From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Date: Mon, 5 Nov 2018 16:06:06 +0200
> Subject: [PATCH] x86/cpu/intel: clean up detect_sgx() flow
>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> arch/x86/kernel/cpu/intel.c | 32 ++++++++++++++++++++------------
> 1 file changed, 20 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index bc52c52f7025..8a20a193d399 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -598,28 +598,36 @@ static void detect_tme(struct cpuinfo_x86 *c)
>
> 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)) {
> + goto out_unsupported;
> + }
> +
> + 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)) {
> + goto out_unsupported;
> + }
> +
> + if (!cpu_has(c, X86_FEATURE_SGX1)) {
> pr_err_once("sgx: SGX1 instruction set not supported\n");
> - unsupported = true;
> + goto out_unsupported;
> }
>
> - if (unsupported) {
> - setup_clear_cpu_cap(X86_FEATURE_SGX);
> - setup_clear_cpu_cap(X86_FEATURE_SGX1);
> - setup_clear_cpu_cap(X86_FEATURE_SGX2);
> + if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) {
> + pr_info_once("sgx: launch control MSRs are not writable\n");
> + goto out_msrs_rdonly;
> }
> - if (unsupported || !(fc & FEATURE_CONTROL_SGX_LE_WR))
> - setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
> +
> + 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);
> }
>
> static void init_intel_energy_perf(struct cpuinfo_x86 *c)
> --
> 2.19.1
>


--
With Best Regards,
Andy Shevchenko


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