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From: Kai Huang <kai.huang@intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org, linux-sgx@vger.kernel.org
Cc: seanjc@google.com, bp@alien8.de, jarkko@kernel.org,
	dave.hansen@intel.com, luto@kernel.org,
	rick.p.edgecombe@intel.com, haitao.huang@intel.com
Subject: Re: [PATCH v5 10/11] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC
Date: Mon, 19 Apr 2021 23:44:14 +1200	[thread overview]
Message-ID: <3d376fef419077376eecb017ab494ba7ffc393a7.camel@intel.com> (raw)
In-Reply-To: <9f568584-8b09-afe6-30a1-cbe280749f5d@redhat.com>

On Sat, 2021-04-17 at 16:11 +0200, Paolo Bonzini wrote:
> On 12/04/21 06:21, Kai Huang wrote:
> > @@ -4377,6 +4380,15 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
> >   	if (!vcpu->kvm->arch.bus_lock_detection_enabled)
> >   		exec_control &= ~SECONDARY_EXEC_BUS_LOCK_DETECTION;
> >   
> > 
> > +	if (cpu_has_vmx_encls_vmexit() && nested) {
> > +		if (guest_cpuid_has(vcpu, X86_FEATURE_SGX))
> > +			vmx->nested.msrs.secondary_ctls_high |=
> > +				SECONDARY_EXEC_ENCLS_EXITING;
> > +		else
> > +			vmx->nested.msrs.secondary_ctls_high &=
> > +				~SECONDARY_EXEC_ENCLS_EXITING;
> > +	}
> > +
> 
> This is incorrect, I've removed it.  The MSRs can only be written by 
> userspace.
> 
> If SGX is disabled in the guest CPUID, nested_vmx_exit_handled_encls can 
> just do:
> 
> 	if (!guest_cpuid_has(vcpu, X86_FEATURE_SGX) ||
> 	    !nested_cpu_has2(vmcs12, SECONDARY_EXEC_ENCLS_EXITING))
> 		return false;
> 
> and the useless ENCLS exiting bitmap in vmcs12 will be ignored.
> 
> Paolo
> 

Thanks for queuing this series!

Looks good to me. However if I read code correctly, in this way a side effect would be
vmx->nested.msrs.secondary_ctls_high will always have SECONDARY_EXEC_ENCLS_EXITING bit
set, even SGX is not exposed to guest, which means a guest can set this even SGX is not
present, but I think it is OK since ENCLS exiting bitmap in vmcs12 will be ignored anyway
in nested_vmx_exit_handled_encls() as you mentioned above.

Anyway, I have tested this code and it works at my side (by creating L2 with SGX support
and running SGX workloads inside it).

Sean, please also comment if you have any.



  reply	other threads:[~2021-04-19 11:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-12  4:21 [PATCH v5 00/11] KVM SGX virtualization support (KVM part) Kai Huang
2021-04-12  4:21 ` [PATCH v5 01/11] KVM: x86: Export kvm_mmu_gva_to_gpa_{read,write}() for SGX (VMX) Kai Huang
2021-04-12  4:21 ` [PATCH v5 02/11] KVM: x86: Define new #PF SGX error code bit Kai Huang
2021-04-12  4:21 ` [PATCH v5 03/11] KVM: x86: Add support for reverse CPUID lookup of scattered features Kai Huang
2021-04-17 13:39   ` Paolo Bonzini
2021-04-12  4:21 ` [PATCH v5 04/11] KVM: x86: Add reverse-CPUID lookup support for scattered SGX features Kai Huang
2021-04-17 13:39   ` Paolo Bonzini
2021-04-12  4:21 ` [PATCH v5 05/11] KVM: VMX: Add basic handling of VM-Exit from SGX enclave Kai Huang
2021-04-12  4:21 ` [PATCH v5 06/11] KVM: VMX: Frame in ENCLS handler for SGX virtualization Kai Huang
2021-04-12  4:21 ` [PATCH v5 07/11] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Kai Huang
2021-04-12  4:21 ` [PATCH v5 08/11] KVM: VMX: Add emulation of SGX Launch Control LE hash MSRs Kai Huang
2021-04-17 13:55   ` Paolo Bonzini
2021-04-12  4:21 ` [PATCH v5 09/11] KVM: VMX: Add ENCLS[EINIT] handler to support SGX Launch Control (LC) Kai Huang
2021-04-12  4:21 ` [PATCH v5 10/11] KVM: VMX: Enable SGX virtualization for SGX1, SGX2 and LC Kai Huang
2021-04-12  9:51   ` kernel test robot
2021-04-12 10:47     ` Kai Huang
2021-04-17 14:11   ` Paolo Bonzini
2021-04-19 11:44     ` Kai Huang [this message]
2021-04-19 15:16       ` Sean Christopherson
2021-04-19 17:14         ` Paolo Bonzini
2021-04-12  4:21 ` [PATCH v5 11/11] KVM: x86: Add capability to grant VM access to privileged SGX attribute Kai Huang
2021-04-12 11:28   ` kernel test robot
2021-04-13 14:51 ` [PATCH v5 00/11] KVM SGX virtualization support (KVM part) Paolo Bonzini
2021-04-13 15:01   ` Borislav Petkov
2021-04-13 21:47     ` Kai Huang
2021-04-17 14:15 ` Paolo Bonzini

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