KVM: nVMX: Fix loss of pending IRQ/NMI before entering L2 (b5861e5c) · Commits · 戴 / test

Consider the case L1 had a IRQ/NMI event until it executed VMLAUNCH/VMRESUME which wasn't delivered because it was disallowed (e.g. interrupts disabled). When L1 executes VMLAUNCH/VMRESUME, L0 needs to evaluate if this pending event should cause an exit from L2 to L1 or delivered directly to L2 (e.g. In case L1 don't intercept EXTERNAL_INTERRUPT). Usually this would be handled by L0 requesting a IRQ/NMI window by setting VMCS accordingly. However, this setting was done on VMCS01 and now VMCS02 is active instead. Thus, when L1 executes VMLAUNCH/VMRESUME we force L0 to perform pending event evaluation by requesting a KVM_REQ_EVENT. Note that above scenario exists when L1 KVM is about to enter L2 but requests an "immediate-exit". As in this case, L1 will disable-interrupts and then send a self-IPI before entering L2. Reviewed-by:

Nikita Leshchenko <nikita.leshchenko@oracle.com> Co-developed-by:

Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by:

Liran Alon <liran.alon@oracle.com> Signed-off-by:

Radim Krčmář <rkrcmar@redhat.com>

arch/x86/kvm/vmx.c

+22 −0

Original line number	Diff line number	Diff line
		@@ -12537,8 +12537,11 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu vcpu, u32 exit_qual)
		struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
		bool from_vmentry = !!exit_qual;
		u32 dummy_exit_qual;
		u32 vmcs01_cpu_exec_ctrl;
		int r = 0;

		vmcs01_cpu_exec_ctrl = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);

		enter_guest_mode(vcpu);

		if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS))
		@@ -12574,6 +12577,25 @@ static int enter_vmx_non_root_mode(struct kvm_vcpu vcpu, u32 exit_qual)
		kvm_make_request(KVM_REQ_GET_VMCS12_PAGES, vcpu);
		}

		/*
		* If L1 had a pending IRQ/NMI until it executed
		* VMLAUNCH/VMRESUME which wasn't delivered because it was
		* disallowed (e.g. interrupts disabled), L0 needs to
		* evaluate if this pending event should cause an exit from L2
		* to L1 or delivered directly to L2 (e.g. In case L1 don't
		* intercept EXTERNAL_INTERRUPT).
		*
		* Usually this would be handled by L0 requesting a
		* IRQ/NMI window by setting VMCS accordingly. However,
		* this setting was done on VMCS01 and now VMCS02 is active
		* instead. Thus, we force L0 to perform pending event
		* evaluation by requesting a KVM_REQ_EVENT.
		*/
		if (vmcs01_cpu_exec_ctrl &
		(CPU_BASED_VIRTUAL_INTR_PENDING \| CPU_BASED_VIRTUAL_NMI_PENDING)) {
		kvm_make_request(KVM_REQ_EVENT, vcpu);
		}

		/*
		* Note no nested_vmx_succeed or nested_vmx_fail here. At this point
		* we are no longer running L1, and VMLAUNCH/VMRESUME has not yet

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