Re: [RESEND PATCH 4/6] x86/traps: add external_interrupt() to dispatch external interrupts

[Sean Christopherson]

On Wed, Nov 09, 2022, Xin Li wrote:
> +__visible noinstr void external_interrupt(struct pt_regs *regs,
> +					  unsigned int vector)
> +{
> +	unsigned int sysvec = vector - FIRST_SYSTEM_VECTOR;
> +
> +	BUG_ON(vector < FIRST_EXTERNAL_VECTOR);

Why not return an error up the stack?  KVM and/or CPU bugs aren't unheard of.
Dropping an IRQ obviously isn't ideal, but there's a non-zero chance that letting
KVM WARN and kill the VM will keep the host alive and thus other VMs running.  A
somewhat sophisticated setup might even react to the VM being killed by migrating
other VMs off the system and initiating host maintenance.