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 18/21] KVM: x86: Invoke kvm_x86_ops->cpuid_update() after kvm_update_cpuid()
Date: Fri, 26 Jul 2019 22:52:11 -0700 [thread overview]
Message-ID: <20190727055214.9282-19-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20190727055214.9282-1-sean.j.christopherson@intel.com>
VMX's virtualization of SGX adds a lovely dependency on the guest's
supported xcr0, which is calculated in kvm_update_cpuid(). VMX must
toggled its interception of SGX instructions based on the supported
xcr0, i.e. kvm_x86_ops->cpuid_update() is certainly the correct
location for the dependent code.
kvm_update_cpuid() was originally added by commit 2acf923e38fb ("KVM:
VMX: Enable XSAVE/XRSTOR for guest"). There is no indication that its
placement after kvm_x86_ops->cpuid_update() was anything more than a
"new function at the end" decision.
Inspection of the current code reveals no dependency on kvm_x86_ops's
cpuid_update() in kvm_update_cpuid() or any of its helpers.
- SVM's sole update is to conditionally clear X86_FEATURE_X2APIC.
X86_FEATURE_X2APIC is only consumed by kvm_apic_set_state(), which
is already called immediately prior to kvm_x86_ops->cpuid_update().
- VMX updates only nested VMX MSRs, allowed FEATURE_CONTROL bits,
and VMCS fields, e.g. secondary execution controls, none of which
should bleed back into kvm_update_cpuid() barring an egregious
dependency bug somewhere else.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/cpuid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 70e488951f25..4c235af5318c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -222,8 +222,9 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
vcpu->arch.cpuid_nent = cpuid->nent;
cpuid_fix_nx_cap(vcpu);
kvm_apic_set_version(vcpu);
- kvm_x86_ops->cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
+ if (!r)
+ kvm_x86_ops->cpuid_update(vcpu);
out:
vfree(cpuid_entries);
@@ -245,8 +246,9 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
goto out;
vcpu->arch.cpuid_nent = cpuid->nent;
kvm_apic_set_version(vcpu);
- kvm_x86_ops->cpuid_update(vcpu);
r = kvm_update_cpuid(vcpu);
+ if (!r)
+ kvm_x86_ops->cpuid_update(vcpu);
out:
return r;
}
--
2.22.0
next prev parent reply other threads:[~2019-07-27 5:53 UTC|newest]
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 ` [RFC PATCH 17/21] KVM: VMX: Add handler for ENCLS[EINIT] to support SGX Launch Control Sean Christopherson
2019-07-27 5:52 ` Sean Christopherson [this message]
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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