Re: [PATCH v3 1/2] x86/kvm/vmx: Move IRQ/NMI dispatch from KVM into x86 core

[Sean Christopherson <seanjc@google.com>]

On Fri, May 08, 2026, Peter Zijlstra wrote:
> 
> Move the VMX interrupt dispatch magic into the x86 core code. This
> isolates KVM from the FRED/IDT decisions and reduces the amount of
> EXPORT_SYMBOL_FOR_KVM().
> 
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Tested-by: Vishal L Verma <vishal.l.verma@intel.com>
> ---

Acked-by: Sean Christopherson <seanjc@google.com>

> @@ -7152,17 +7149,9 @@ static void handle_external_interrupt_ir
>  	    "unexpected VM-Exit interrupt info: 0x%x", intr_info))
>  		return;
>  
> -	/*
> -	 * Invoke the kernel's IRQ handler for the vector.  Use the FRED path
> -	 * when it's available even if FRED isn't fully enabled, e.g. even if
> -	 * FRED isn't supported in hardware, in order to avoid the indirect
> -	 * CALL in the non-FRED path.
> -	 */
> +	/* For the IRQ to the core kernel for processing. */

Forward?  Or just delete this comment entirely, either way works for me.

>  	kvm_before_interrupt(vcpu, KVM_HANDLING_IRQ);
> -	if (IS_ENABLED(CONFIG_X86_FRED))
> -		fred_entry_from_kvm(EVENT_TYPE_EXTINT, vector);
> -	else
> -		vmx_do_interrupt_irqoff(gate_offset((gate_desc *)host_idt_base + vector));
> +	x86_entry_from_kvm(EVENT_TYPE_EXTINT, vector);
>  	kvm_after_interrupt(vcpu);
>  
>  	vcpu->arch.at_instruction_boundary = true;