1 files changed, 83 insertions, 0 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index e773f3d8e188..e0a93d974829 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3954,6 +3954,89 @@ static bool nested_vmx_preemption_timer_pending(struct kvm_vcpu *vcpu)
 	       to_vmx(vcpu)->nested.preemption_timer_expired;
 }
 
+/*
+ * Per the Intel SDM's table "Priority Among Concurrent Events", with minor
+ * edits to fill in missing examples, e.g. #DB due to split-lock accesses,
+ * and less minor edits to splice in the priority of VMX Non-Root specific
+ * events, e.g. MTF and NMI/INTR-window exiting.
+ *
+ * 1 Hardware Reset and Machine Checks
+ *	- RESET
+ *	- Machine Check
+ *
+ * 2 Trap on Task Switch
+ *	- T flag in TSS is set (on task switch)
+ *
+ * 3 External Hardware Interventions
+ *	- FLUSH
+ *	- STOPCLK
+ *	- SMI
+ *	- INIT
+ *
+ * 3.5 Monitor Trap Flag (MTF) VM-exit[1]
+ *
+ * 4 Traps on Previous Instruction
+ *	- Breakpoints
+ *	- Trap-class Debug Exceptions (#DB due to TF flag set, data/I-O
+ *	  breakpoint, or #DB due to a split-lock access)
+ *
+ * 4.3	VMX-preemption timer expired VM-exit
+ *
+ * 4.6	NMI-window exiting VM-exit[2]
+ *
+ * 5 Nonmaskable Interrupts (NMI)
+ *
+ * 5.5 Interrupt-window exiting VM-exit and Virtual-interrupt delivery
+ *
+ * 6 Maskable Hardware Interrupts
+ *
+ * 7 Code Breakpoint Fault
+ *
+ * 8 Faults from Fetching Next Instruction
+ *	- Code-Segment Limit Violation
+ *	- Code Page Fault
+ *	- Control protection exception (missing ENDBRANCH at target of indirect
+ *					call or jump)
+ *
+ * 9 Faults from Decoding Next Instruction
+ *	- Instruction length > 15 bytes
+ *	- Invalid Opcode
+ *	- Coprocessor Not Available
+ *
+ *10 Faults on Executing Instruction
+ *	- Overflow
+ *	- Bound error
+ *	- Invalid TSS
+ *	- Segment Not Present
+ *	- Stack fault
+ *	- General Protection
+ *	- Data Page Fault
+ *	- Alignment Check
+ *	- x86 FPU Floating-point exception
+ *	- SIMD floating-point exception
+ *	- Virtualization exception
+ *	- Control protection exception
+ *
+ * [1] Per the "Monitor Trap Flag" section: System-management interrupts (SMIs),
+ *     INIT signals, and higher priority events take priority over MTF VM exits.
+ *     MTF VM exits take priority over debug-trap exceptions and lower priority
+ *     events.
+ *
+ * [2] Debug-trap exceptions and higher priority events take priority over VM exits
+ *     caused by the VMX-preemption timer.  VM exits caused by the VMX-preemption
+ *     timer take priority over VM exits caused by the "NMI-window exiting"
+ *     VM-execution control and lower priority events.
+ *
+ * [3] Debug-trap exceptions and higher priority events take priority over VM exits
+ *     caused by "NMI-window exiting".  VM exits caused by this control take
+ *     priority over non-maskable interrupts (NMIs) and lower priority events.
+ *
+ * [4] Virtual-interrupt delivery has the same priority as that of VM exits due to
+ *     the 1-setting of the "interrupt-window exiting" VM-execution control.  Thus,
+ *     non-maskable interrupts (NMIs) and higher priority events take priority over
+ *     delivery of a virtual interrupt; delivery of a virtual interrupt takes
+ *     priority over external interrupts and lower priority events.
+ */
 static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
 {
 	struct kvm_lapic *apic = vcpu->arch.apic;