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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
	dave.hansen@intel.com, sean.j.christopherson@intel.com,
	nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com,
	shay.katz-zamir@intel.com, haitao.huang@intel.com,
	andriy.shevchenko@linux.intel.com, tglx@linutronix.de,
	kai.svahn@intel.com, josh@joshtriplett.org, luto@kernel.org,
	kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com,
	puiterwijk@redhat.com
Subject: Re: [PATCH v24 07/24] x86/cpu/intel: Detect SGX supprt
Date: Fri, 27 Dec 2019 08:00:50 +0200
Message-ID: <05875955d6a4de39a2686ac62e7b2b8583450b49.camel@linux.intel.com> (raw)
In-Reply-To: <20191223094614.GB16710@zn.tnic>

On Mon, 2019-12-23 at 10:46 +0100, Borislav Petkov wrote:
> On Sat, Nov 30, 2019 at 01:13:09AM +0200, Jarkko Sakkinen wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > When the CPU supports SGX, check that the BIOS has enabled SGX and SGX1
> > opcodes are available. Otherwise, all the SGX related capabilities.
> > 
> > In addition, clear X86_FEATURE_SGX_LC also in the case when the launch
> > enclave are read-only. This way the feature bit reflects the level that
> > Linux supports the launch control.
> > 
> > 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.
> > 
> > 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>
> > ---
> >  arch/x86/kernel/cpu/intel.c | 41 +++++++++++++++++++++++++++++++++++++
> >  1 file changed, 41 insertions(+)
> > 
> > diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> > index c2fdc00df163..89a71367716c 100644
> > --- a/arch/x86/kernel/cpu/intel.c
> > +++ b/arch/x86/kernel/cpu/intel.c
> > @@ -624,6 +624,42 @@ static void detect_tme(struct cpuinfo_x86 *c)
> >  	c->x86_phys_bits -= keyid_bits;
> >  }
> >  
> > +static void __maybe_unused 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: The feature control MSR is not locked\n");
> > +		goto err_unsupported;
> > +	}
> > +
> > +	if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) {
> > +		pr_err_once("sgx: SGX is not enabled in IA32_FEATURE_CONTROL MSR\n");
> > +		goto err_unsupported;
> > +	}
> > +
> > +	if (!cpu_has(c, X86_FEATURE_SGX1)) {
> > +		pr_err_once("sgx: SGX1 instruction set is not supported\n");
> > +		goto err_unsupported;
> > +	}
> > +
> > +	if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) {
> > +		pr_info_once("sgx: The launch control MSRs are not writable\n");
> > +		goto err_msrs_rdonly;
> > +	}
> 
> One more thing - and we talked about this already - when the hash
> MSRs are not writable, the kernel needs to disable all SGX support by
> default. Basically, no SGX support is present.
> 
> If the user wants to run KVM guests with SGX enclaves, then she should
> probably boot with a special kvm param or so. Details on how can exactly
> control that can be discussed later - just making sure you guys are not
> forgetting this use angle.
> 
> Thx.

Sure.

Overally, I guess the right marching order is to hold on with the 
next version of SGX patch set up until Sean's other patch set is
ready to be merged.

/Jarkko




  reply index

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-29 23:13 [PATCH v24 00/24] Intel SGX foundations Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 01/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-11-30  1:38   ` Neil Horman
2019-11-30 14:37     ` Dr. Greg
2019-12-02  9:24       ` Jethro Beekman
2019-12-06 21:23     ` Jarkko Sakkinen
2019-12-06 21:24       ` Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 02/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 03/24] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 04/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 05/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 06/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-12-17 14:45   ` Borislav Petkov
2019-12-19  0:39     ` Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 07/24] x86/cpu/intel: Detect SGX supprt Jarkko Sakkinen
2019-12-17 15:17   ` Borislav Petkov
2019-12-19  0:42     ` Jarkko Sakkinen
2019-12-19  6:15       ` Borislav Petkov
2019-12-23  9:46   ` Borislav Petkov
2019-12-27  6:00     ` Jarkko Sakkinen [this message]
2020-01-14 18:36     ` Sean Christopherson
2019-11-29 23:13 ` [PATCH v24 08/24] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-12-18  9:18   ` Borislav Petkov
2019-12-18 15:19     ` Sean Christopherson
2019-12-18 16:18       ` Borislav Petkov
2019-12-19  0:53     ` Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 09/24] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 10/24] x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT] Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 11/24] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 12/24] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2019-12-02 15:48   ` Haitao Huang
2019-12-02 18:21     ` Sean Christopherson
2019-12-09 19:38       ` Jarkko Sakkinen
2019-12-09 19:08     ` Jarkko Sakkinen
2020-01-14 16:12   ` Haitao Huang
2019-11-29 23:13 ` [PATCH v24 13/24] selftests/x86: Recurse into subdirectories Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 14/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 15/24] x86/sgx: Add provisioning Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 16/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 17/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 18/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 19/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 20/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 21/24] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 22/24] selftests/x86: Add vDSO selftest for SGX Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 23/24] docs: x86/sgx: Document microarchitecture Jarkko Sakkinen
2019-11-29 23:13 ` [PATCH v24 24/24] docs: x86/sgx: Document kernel internals Jarkko Sakkinen
2019-12-20 13:26 ` [PATCH v24 00/24] Intel SGX foundations Nathaniel McCallum

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