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authorSean Christopherson <sean.j.christopherson@intel.com>2018-03-12 10:56:13 -0700
committerPaolo Bonzini <pbonzini@redhat.com>2018-03-16 22:01:38 +0100
commit2bb8cafea80bf69c0e729bf1ad1bcd1d6c53248d (patch)
tree38958959d708fa92778368a7e269fe9b474e465f /arch/x86
parente1de91ccab311ec8007c6e77b0dbb4e3421fd298 (diff)
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KVM: vVMX: signal failure for nested VMEntry if emulation_required
Fail a nested VMEntry with EXIT_REASON_INVALID_STATE if L2 guest state is invalid, i.e. vmcs12 contained invalid guest state, and unrestricted guest is disabled in L0 (and by extension disabled in L1). WARN_ON_ONCE in handle_invalid_guest_state() if we're attempting to emulate L2, i.e. nested_run_pending is true, to aid debug in the (hopefully unlikely) scenario that we somehow skip the nested VMEntry consistency check, e.g. due to a L0 bug. Note: KVM relies on hardware to detect the scenario where unrestricted guest is enabled in L0 but disabled in L1 and vmcs12 contains invalid guest state, i.e. checking emulation_required in prepare_vmcs02 is required only to handle the case were unrestricted guest is disabled in L0 since L0 never actually attempts VMLAUNCH/VMRESUME with vmcs02. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kvm/vmx.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6cefd7b3ff7f..5d67a15b5116 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6865,6 +6865,13 @@ static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
bool intr_window_requested;
unsigned count = 130;
+ /*
+ * We should never reach the point where we are emulating L2
+ * due to invalid guest state as that means we incorrectly
+ * allowed a nested VMEntry with an invalid vmcs12.
+ */
+ WARN_ON_ONCE(vmx->emulation_required && vmx->nested.nested_run_pending);
+
cpu_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
intr_window_requested = cpu_exec_ctrl & CPU_BASED_VIRTUAL_INTR_PENDING;
@@ -10990,6 +10997,14 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12,
vmx->nested.dirty_vmcs12 = false;
}
+ /*
+ * Guest state is invalid and unrestricted guest is disabled,
+ * which means L1 attempted VMEntry to L2 with invalid state.
+ * Fail the VMEntry.
+ */
+ if (vmx->emulation_required)
+ return 1;
+
/* Shadow page tables on either EPT or shadow page tables. */
if (nested_vmx_load_cr3(vcpu, vmcs12->guest_cr3, nested_cpu_has_ept(vmcs12),
entry_failure_code))