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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	x86@kernel.org,
	"Jarkko Sakkinen" <jarkko.sakkinen@linux.intel.com>,
	"Sean Christopherson" <sean.j.christopherson@intel.com>,
	"Joerg Roedel" <joro@8bytes.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-sgx@vger.kernel.org, Andy Lutomirski <luto@amacapital.net>
Subject: [RFC PATCH 17/21] KVM: VMX: Add handler for ENCLS[EINIT] to support SGX Launch Control
Date: Fri, 26 Jul 2019 22:52:10 -0700
Message-ID: <20190727055214.9282-18-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190727055214.9282-1-sean.j.christopherson@intel.com>

SGX Launch Control (LC) modifies the behavior of ENCLS[EINIT] to query
a set of user-controllable MSRs (Launch Enclave, a.k.a. LE, Hash MSRs)
when verifying the key used to sign an enclave.  On CPUs without LC
support, the public key hash of allowed LEs is hardwired into the CPU to
an Intel controlled key (the Intel key is also the reset value of the LE
hash MSRs).

When LC is enabled in the host, EINIT must be intercepted and executed
in the host using the guest's LE hash MSR value, even if the guest's
values are fixed to hardware default values.  The MSRs are not switched
on VM-Enter/VM-Exit as writing the MSRs is extraordinarily expensive,
e.g. each WRMSR is 4x slower than a regular WRMSR and on par with a full
VM-Enter -> VM-Exit transition.  Furthermore, as the MSRS aren't allowed
in the hardware-supported lists, i.e. would need to be manually read and
written.  On the other hand, EINIT takes tens of thousands of cycles to
execute (it's so slow that it's interruptible), i.e. the ~1k cycles of
overhead to trap-and-execute EINIT is unlikely to be noticed by the
guest, let alone impact the overall performance of SGX.

Actual usage of the handler will be added in a future patch, i.e. when
SGX virtualization is fully enabled.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/sgx.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 5b08e7dcc3a3..2bcfa3b6c75e 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -221,3 +221,27 @@ int handle_encls_ecreate(struct kvm_vcpu *vcpu)
 
 	return sgx_encls_postamble(vcpu, ret, trapnr, secs_gva);
 }
+
+int handle_encls_einit(struct kvm_vcpu *vcpu)
+{
+	unsigned long sig_hva, secs_hva, token_hva;
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	gva_t sig_gva, secs_gva, token_gva;
+	int ret, trapnr;
+
+	if (sgx_get_encls_gva(vcpu, kvm_rbx_read(vcpu), 1808, 4096, &sig_gva) ||
+	    sgx_get_encls_gva(vcpu, kvm_rcx_read(vcpu), 4096, 4096, &secs_gva) ||
+	    sgx_get_encls_gva(vcpu, kvm_rdx_read(vcpu), 304, 512, &token_gva))
+		return 1;
+
+	if (sgx_gva_to_hva(vcpu, sig_gva, false, &sig_hva) ||
+	    sgx_gva_to_hva(vcpu, secs_gva, true, &secs_hva) ||
+	    sgx_gva_to_hva(vcpu, token_gva, false, &token_hva))
+		return 1;
+
+	ret = sgx_einit((void __user *)sig_hva, (void __user *)token_hva,
+			(void __user *)secs_hva, vmx->msr_ia32_sgxlepubkeyhash,
+			&trapnr);
+
+	return sgx_encls_postamble(vcpu, ret, trapnr, secs_hva);
+}
-- 
2.22.0


  parent reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-27  5:51 [RFC PATCH 00/21] x86/sgx: KVM: Add SGX virtualization Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 01/21] x86/sgx: Add defines for SGX device minor numbers Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 02/21] x86/sgx: Move bus registration and device init to common code Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 03/21] x86/sgx: Move provisioning device " Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 04/21] x86/sgx: Add /dev/sgx/virt_epc device to allocate "raw" EPC for VMs Sean Christopherson
2019-07-27 17:44   ` Andy Lutomirski
2019-07-29 17:05     ` Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 05/21] x86/sgx: Expose SGX architectural definitions to the kernel Sean Christopherson
2019-07-27  5:51 ` [RFC PATCH 06/21] KVM: x86: Add SGX sub-features leaf to reverse CPUID table Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 07/21] KVM: x86: Add WARN_ON_ONCE(index!=0) in __do_cpuid_ent Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 08/21] KVM: x86: Add kvm_x86_ops hook to short circuit emulation Sean Christopherson
2019-07-27 17:38   ` Andy Lutomirski
2019-07-30  2:49     ` Sean Christopherson
2019-08-16  0:47       ` Andy Lutomirski
2019-08-19 22:01         ` Sean Christopherson
2019-08-20  1:34           ` Andy Lutomirski
2019-08-20  1:41             ` Sean Christopherson
2019-07-30  3:08   ` Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 09/21] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 10/21] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for VMX/SGX Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 11/21] KVM: x86: Export kvm_propagate_fault (as kvm_propagate_page_fault) Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 12/21] KVM: x86: Define new #PF SGX error code bit Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 13/21] x86/sgx: Move the intermediate EINIT helper into the driver Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 14/21] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 15/21] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 16/21] KVM: VMX: Edd emulation of SGX Launch Control LE hash MSRs Sean Christopherson
2019-07-27  5:52 ` Sean Christopherson [this message]
2019-07-27  5:52 ` [RFC PATCH 18/21] KVM: x86: Invoke kvm_x86_ops->cpuid_update() after kvm_update_cpuid() Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 19/21] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 20/21] x86/sgx: Export sgx_set_attribute() for use by KVM Sean Christopherson
2019-07-27  5:52 ` [RFC PATCH 21/21] KVM: x86: Add capability to grant VM access to privileged SGX attribute Sean Christopherson
2019-07-27 17:32   ` Andy Lutomirski

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