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[v2,7/7] KVM: nVMX: WARN on attempt to switch the currently loaded VMCS

Message ID 20200923184452.980-8-sean.j.christopherson@intel.com (mailing list archive)
State New, archived
Headers show
Series KVM: nVMX: Bug fixes and cleanup | expand

Commit Message

Sean Christopherson Sept. 23, 2020, 6:44 p.m. UTC
WARN if KVM attempts to switch to the currently loaded VMCS.  Now that
nested_vmx_free_vcpu() doesn't blindly call vmx_switch_vmcs(), all paths
that lead to vmx_switch_vmcs() are implicitly guarded by guest vs. host
mode, e.g. KVM should never emulate VMX instructions when guest mode is
active, and nested_vmx_vmexit() should never be called when host mode is
active.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx/nested.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 63550dcf6b9f..4bddda078370 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -258,7 +258,7 @@  static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs)
 	struct loaded_vmcs *prev;
 	int cpu;
 
-	if (vmx->loaded_vmcs == vmcs)
+	if (WARN_ON_ONCE(vmx->loaded_vmcs == vmcs))
 		return;
 
 	cpu = get_cpu();