Re: [PATCH v6 15/19] vfio-user: handle device interrupts

[Stefan Hajnoczi]

On Mon, Mar 07, 2022 at 03:10:41PM +0000, Jag Raman wrote:
> > On Mar 7, 2022, at 5:24 AM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > On Thu, Feb 17, 2022 at 02:49:02AM -0500, Jagannathan Raman wrote:
> >> @@ -332,6 +336,13 @@ void msi_notify(PCIDevice *dev, unsigned int vector)
> >>     msi_send_message(dev, msg);
> >> }
> >> 
> >> +void msi_notify(PCIDevice *dev, unsigned int vector)
> >> +{
> >> +    if (dev->msi_notify) {
> > 
> > Can this ever be NULL?
> 
> Unlikely in the current code flow, but it could change in the future.
> 
> As a matter of principle, I thought that we should check if a function
> pointer is non-NULL before invoking it in QEMU. Is that not the case?

No, it's better to dump core with a backtrace when a program invariant
is violated than to silently suppress it. If msi_notify() is called but
the function pointer is NULL then there is a bug in the program that
needs to be fixed.

Stefan

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