KVM: x86: Rework request for immediate exit
The VMX implementation of enable_irq_window raised
KVM_REQ_IMMEDIATE_EXIT after we checked it in vcpu_enter_guest. This
caused infinite loops on vmentry. Fix it by letting enable_irq_window
signal the need for an immediate exit via its return value and drop
KVM_REQ_IMMEDIATE_EXIT.
This issue only affects nested VMX scenarios.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0f0cb31..74c525e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4398,22 +4398,23 @@
PIN_BASED_NMI_EXITING;
}
-static void enable_irq_window(struct kvm_vcpu *vcpu)
+static int enable_irq_window(struct kvm_vcpu *vcpu)
{
u32 cpu_based_vm_exec_control;
- if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu)) {
+
+ if (is_guest_mode(vcpu) && nested_exit_on_intr(vcpu))
/*
* We get here if vmx_interrupt_allowed() said we can't
- * inject to L1 now because L2 must run. Ask L2 to exit
- * right after entry, so we can inject to L1 more promptly.
+ * inject to L1 now because L2 must run. The caller will have
+ * to make L2 exit right after entry, so we can inject to L1
+ * more promptly.
*/
- kvm_make_request(KVM_REQ_IMMEDIATE_EXIT, vcpu);
- return;
- }
+ return -EBUSY;
cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_INTR_PENDING;
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+ return 0;
}
static void enable_nmi_window(struct kvm_vcpu *vcpu)
