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From: Darren Kenny <darren.kenny@oracle.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	x86@kernel.org, linux-sgx@vger.kernel.org
Cc: linux-kernel@vger.kernel.org,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
	asapek@google.com, bp@alien8.de, cedric.xing@intel.com,
	chenalexchen@google.com, conradparker@google.com,
	cyhanish@google.com, dave.hansen@intel.com,
	haitao.huang@intel.com, josh@joshtriplett.org,
	kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com,
	ludloff@google.com, luto@kernel.org, nhorman@redhat.com,
	npmccallum@redhat.com, puiterwijk@redhat.com,
	rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com
Subject: Re: [PATCH v36 06/24] x86/cpu/intel: Detect SGX support
Date: Thu, 06 Aug 2020 14:17:47 +0100	[thread overview]
Message-ID: <m2zh77rk04.fsf@oracle.com> (raw)
In-Reply-To: <20200716135303.276442-7-jarkko.sakkinen@linux.intel.com>

On Thursday, 2020-07-16 at 16:52:45 +03, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Configure SGX as part of feature control MSR initialization and update
> the associated X86_FEATURE flags accordingly.  Because the kernel will
> require the LE hash MSRs to be writable when running native enclaves,
> disable X86_FEATURE_SGX (and all derivatives) if SGX Launch Control is
> not (or cannot) be fully enabled via feature control MSR.
>
> The check is done for every CPU, not just BSP, in order to verify that
> MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. The other
> parts of the kernel, like the enclave driver, expect the same
> configuration from all CPUs.
>
> Note, unlike VMX, clear the X86_FEATURE_SGX* flags for all CPUs if any
> CPU lacks SGX support as the kernel expects SGX to be available on all
> CPUs.  X86_FEATURE_VMX is intentionally cleared only for the current CPU
> so that KVM can provide additional information if KVM fails to load,
> e.g. print which CPU doesn't support VMX.  KVM/VMX requires additional
> per-CPU enabling, e.g. to set CR4.VMXE and do VMXON, and so already has
> the necessary infrastructure to do per-CPU checks.  SGX on the other
> hand doesn't require additional enabling, so clearing the feature flags
> on all CPUs means the SGX subsystem doesn't need to manually do support
> checks on a per-CPU basis.
>
> Acked-by: Jethro Beekman <jethro@fortanix.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Reviewed-by: Darren Kenny <darren.kenny@oracle.com>

> ---
>  arch/x86/kernel/cpu/feat_ctl.c | 32 +++++++++++++++++++++++++++++++-
>  1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c
> index 29a3bedabd06..c3afcd2e4342 100644
> --- a/arch/x86/kernel/cpu/feat_ctl.c
> +++ b/arch/x86/kernel/cpu/feat_ctl.c
> @@ -93,16 +93,35 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c)
>  }
>  #endif /* CONFIG_X86_VMX_FEATURE_NAMES */
>  
> +static void clear_sgx_caps(void)
> +{
> +	setup_clear_cpu_cap(X86_FEATURE_SGX);
> +	setup_clear_cpu_cap(X86_FEATURE_SGX_LC);
> +	setup_clear_cpu_cap(X86_FEATURE_SGX1);
> +	setup_clear_cpu_cap(X86_FEATURE_SGX2);
> +}
> +
>  void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  {
>  	bool tboot = tboot_enabled();
> +	bool enable_sgx;
>  	u64 msr;
>  
>  	if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
>  		clear_cpu_cap(c, X86_FEATURE_VMX);
> +		clear_sgx_caps();
>  		return;
>  	}
>  
> +	/*
> +	 * Enable SGX if and only if the kernel supports SGX and Launch Control
> +	 * is supported, i.e. disable SGX if the LE hash MSRs can't be written.
> +	 */
> +	enable_sgx = cpu_has(c, X86_FEATURE_SGX) &&
> +		     cpu_has(c, X86_FEATURE_SGX1) &&
> +		     cpu_has(c, X86_FEATURE_SGX_LC) &&
> +		     IS_ENABLED(CONFIG_INTEL_SGX);
> +
>  	if (msr & FEAT_CTL_LOCKED)
>  		goto update_caps;
>  
> @@ -124,13 +143,16 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  			msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
>  	}
>  
> +	if (enable_sgx)
> +		msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED;
> +
>  	wrmsrl(MSR_IA32_FEAT_CTL, msr);
>  
>  update_caps:
>  	set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL);
>  
>  	if (!cpu_has(c, X86_FEATURE_VMX))
> -		return;
> +		goto update_sgx;
>  
>  	if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
>  	    (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
> @@ -143,4 +165,12 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
>  		init_vmx_capabilities(c);
>  #endif
>  	}
> +
> +update_sgx:
> +	if (!(msr & FEAT_CTL_SGX_ENABLED) ||
> +	    !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) {
> +		if (enable_sgx)
> +			pr_err_once("SGX disabled by BIOS\n");
> +		clear_sgx_caps();
> +	}
>  }
> -- 
> 2.25.1

  reply	other threads:[~2020-08-06 17:58 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16 13:52 [PATCH v36 00/24] Intel SGX foundations Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-08-06 13:13   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 02/24] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-08-06 13:14   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-08-06 13:16   ` Darren Kenny
2020-08-20 15:31   ` Borislav Petkov
2020-08-21 17:35     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 04/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-08-06 13:14   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 05/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-08-07  9:37   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 06/24] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-08-06 13:17   ` Darren Kenny [this message]
2020-07-16 13:52 ` [PATCH v36 07/24] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-08-06 13:18   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 08/24] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-08-06 13:27   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 09/24] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-08-06 13:29   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 10/24] mm: Add vm_ops->mprotect() Jarkko Sakkinen
2020-08-06 13:35   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 11/24] x86/sgx: Add SGX enclave driver Jarkko Sakkinen
2020-08-06 13:59   ` Darren Kenny
2020-08-25 16:44   ` Borislav Petkov
2020-08-26 13:46     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 12/24] x86/sgx: Add SGX_IOC_ENCLAVE_CREATE Jarkko Sakkinen
2020-08-06 15:40   ` Darren Kenny
2020-08-26 14:52   ` Borislav Petkov
2020-08-27 13:24     ` Jarkko Sakkinen
2020-08-27 16:15       ` Borislav Petkov
2020-08-28 23:39         ` Jarkko Sakkinen
2020-08-29  0:21       ` Jarkko Sakkinen
2020-09-01 16:41   ` Haitao Huang
2020-09-04 11:55     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 13/24] x86/sgx: Add SGX_IOC_ENCLAVE_ADD_PAGES Jarkko Sakkinen
2020-08-06 16:29   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 14/24] x86/sgx: Add SGX_IOC_ENCLAVE_INIT Jarkko Sakkinen
2020-08-06 16:40   ` Darren Kenny
2020-07-16 13:52 ` [PATCH v36 15/24] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-08-06 17:00   ` Darren Kenny
2020-08-18 13:30     ` Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-07-16 13:52 ` [PATCH v36 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 21/24] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-08-06 14:55   ` Nathaniel McCallum
2020-08-10 22:23     ` Sean Christopherson
2020-08-11  7:16       ` Jethro Beekman
2020-08-11 14:54         ` Sean Christopherson
2020-08-18 14:52       ` Jarkko Sakkinen
2020-08-18 15:06         ` Jarkko Sakkinen
2020-08-18 15:15           ` Nathaniel McCallum
2020-08-18 16:43             ` Jarkko Sakkinen
2020-08-19 13:33               ` Nathaniel McCallum
2020-08-19 14:00                 ` Jethro Beekman
2020-08-19 21:23                 ` Jarkko Sakkinen
2020-08-10 23:08     ` Andy Lutomirski
2020-08-10 23:48       ` Sean Christopherson
2020-08-11  0:52         ` Andy Lutomirski
2020-08-11 15:16           ` Andy Lutomirski
2020-08-13 19:38             ` Sean Christopherson
2020-08-17 13:12       ` Nathaniel McCallum
2020-08-17 15:01         ` Andy Lutomirski
2020-08-18 15:15       ` Jarkko Sakkinen
2020-08-20  0:19         ` Andy Lutomirski
2020-08-18 14:26     ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 22/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-08-27  4:47   ` Nathaniel McCallum
2020-08-27 15:20     ` Sean Christopherson
2020-08-28 23:27       ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 23/24] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-07-28 21:35   ` Pavel Machek
2020-08-06 10:21     ` Dr. Greg
2020-08-08 22:18       ` Pavel Machek
2020-08-19 20:55     ` Jarkko Sakkinen
2020-07-16 13:53 ` [PATCH v36 24/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen

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