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

[Sean Christopherson <seanjc@google.com>]

On Thu, Nov 10, 2022, Li, Xin3 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.
> 
> Make sense.
> 
> What about having it return a signed integer?

Ya, the standard 0/-errno will do nicely.