[PATCH 2/2] Revert "KVM: nVMX: always use early vmcs check when EPT is disabled"

[Sean Christopherson <sean.j.christopherson@intel.com>]

Now that KVM stuffs vmc01.GUEST_CR3 prior to nested VM-Entry, there is
no need to avoid nested_vmx_restore_host_state() when EPT is disabled
as refreshing vcpu->arch.cr3 from vmcs01.GUEST_CR3 will automagically
obtain the correct value.

This reverts commit 2b27924bb1d48e3775f432b70bdad5e6dd4e7798.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/include/uapi/asm/vmx.h |  1 -
 arch/x86/kvm/vmx/nested.c       | 22 ++--------------------
 2 files changed, 2 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h
index d213ec5c3766..f0b0c90dd398 100644
--- a/arch/x86/include/uapi/asm/vmx.h
+++ b/arch/x86/include/uapi/asm/vmx.h
@@ -146,7 +146,6 @@
 
 #define VMX_ABORT_SAVE_GUEST_MSR_FAIL        1
 #define VMX_ABORT_LOAD_HOST_PDPTE_FAIL       2
-#define VMX_ABORT_VMCS_CORRUPTED             3
 #define VMX_ABORT_LOAD_HOST_MSR_FAIL         4
 
 #endif /* _UAPIVMX_H */
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 92117092f6e9..c17fbe3cc2fb 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3777,18 +3777,8 @@ static void nested_vmx_restore_host_state(struct kvm_vcpu *vcpu)
 	vmx_set_cr4(vcpu, vmcs_readl(CR4_READ_SHADOW));
 
 	nested_ept_uninit_mmu_context(vcpu);
-
-	/*
-	 * This is only valid if EPT is in use, otherwise the vmcs01 GUEST_CR3
-	 * points to shadow pages!  Fortunately we only get here after a WARN_ON
-	 * if EPT is disabled, so a VMabort is perfectly fine.
-	 */
-	if (enable_ept) {
-		vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
-		__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
-	} else {
-		nested_vmx_abort(vcpu, VMX_ABORT_VMCS_CORRUPTED);
-	}
+	vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
+	__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
 
 	/*
 	 * Use ept_save_pdptrs(vcpu) to load the MMU's cached PDPTRs
@@ -5729,14 +5719,6 @@ __init int nested_vmx_hardware_setup(int (*exit_handlers[])(struct kvm_vcpu *))
 {
 	int i;
 
-	/*
-	 * Without EPT it is not possible to restore L1's CR3 and PDPTR on
-	 * VMfail, because they are not available in vmcs01.  Just always
-	 * use hardware checks.
-	 */
-	if (!enable_ept)
-		nested_early_check = 1;
-
 	if (!cpu_has_vmx_shadow_vmcs())
 		enable_shadow_vmcs = 0;
 	if (enable_shadow_vmcs) {
-- 
2.21.0