KVM: nVMX: Always sync GUEST_BNDCFGS when it comes from vmcs01

If L1 does not set VM_ENTRY_LOAD_BNDCFGS, then L1's BNDCFGS value must
be propagated to vmcs02 since KVM always runs with VM_ENTRY_LOAD_BNDCFGS
when MPX is supported.  Because the value effectively comes from vmcs01,
vmcs02 must be updated even if vmcs12 is clean.

Fixes: 62cf9bd8118c4 ("KVM: nVMX: Fix emulation of VM_ENTRY_LOAD_BNDCFGS")
Cc: stable@vger.kernel.org
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 6e82bbc..c4c0a45 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2228,13 +2228,9 @@ static void prepare_vmcs02_rare(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12)
 
        set_cr4_guest_host_mask(vmx);
 
-       if (kvm_mpx_supported()) {
-               if (vmx->nested.nested_run_pending &&
-                       (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
-                       vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
-               else
-                       vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs);
-       }
+       if (kvm_mpx_supported() && vmx->nested.nested_run_pending &&
+           (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS))
+               vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
 }
 
 /*
@@ -2266,6 +2262,9 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
                kvm_set_dr(vcpu, 7, vcpu->arch.dr7);
                vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl);
        }
+       if (kvm_mpx_supported() && (!vmx->nested.nested_run_pending ||
+           !(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)))
+               vmcs_write64(GUEST_BNDCFGS, vmx->nested.vmcs01_guest_bndcfgs);
        vmx_set_rflags(vcpu, vmcs12->guest_rflags);
 
        /* EXCEPTION_BITMAP and CR0_GUEST_HOST_MASK should basically be the