linux-kernel - [PATCH 1/2] KVM: VMX: Inject #GP on ENCLS if vCPU has paging disabled (CR0.PG==0)

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Message-ID: <20230405234556.696927-2-seanjc@google.com>
Date:   Wed,  5 Apr 2023 16:45:55 -0700
From:   Sean Christopherson <seanjc@...gle.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Binbin Wu <binbin.wu@...ux.intel.com>,
        Kai Huang <kai.huang@...el.com>
Subject: [PATCH 1/2] KVM: VMX: Inject #GP on ENCLS if vCPU has paging disabled (CR0.PG==0)

Inject a #GP when emulating/forwarding a valid ENCLS leaf if the vCPU has
paging disabled, e.g. if KVM is intercepting ECREATE to enforce additional
restrictions.  The pseudocode in the SDM lists all #GP triggers, including
CR0.PG=0, as being checked after the ENLCS-exiting checks, i.e. the
VM-Exit will occur before the CPU performs the CR0.PG check.

Fixes: 70210c044b4e ("KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions")
Cc: Binbin Wu <binbin.wu@...ux.intel.com>
Cc: Kai Huang <kai.huang@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/kvm/vmx/sgx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index aa53c98034bf..f881f6ff6408 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -375,7 +375,7 @@ int handle_encls(struct kvm_vcpu *vcpu)
 
 	if (!encls_leaf_enabled_in_guest(vcpu, leaf)) {
 		kvm_queue_exception(vcpu, UD_VECTOR);
-	} else if (!sgx_enabled_in_guest_bios(vcpu)) {
+	} else if (!sgx_enabled_in_guest_bios(vcpu) || !is_paging(vcpu)) {
 		kvm_inject_gp(vcpu, 0);
 	} else {
 		if (leaf == ECREATE)
-- 
2.40.0.348.gf938b09366-goog