RE: [PATCH v5 5/9] iommufd: Add iommufd fault object

[Tian, Kevin]

> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Monday, May 20, 2024 9:34 AM
> 
> On 5/15/24 4:37 PM, Tian, Kevin wrote:
> >> +
> >> +		iopf_group_response(group, response.code);
> > PCIe spec states that a response failure disables the PRI interface. For SR-
> IOV
> > it'd be dangerous allowing user to trigger such code to VF to close the
> entire
> > shared PRI interface.
> >
> > Just another example lacking of coordination for shared capabilities
> between
> > PF/VF. But exposing such gap to userspace makes it worse.
> 
> Yes. You are right.
> 
> >
> > I guess we don't want to make this work depending on that cleanup. The
> > minimal correct thing is to disallow attaching VF to a fault-capable hwpt
> > with a note here that once we turn on support for VF the response failure
> > code should not be forwarded to the hardware. Instead it's an indication
> > that the user cannot serve more requests and such situation waits for
> > a vPRI reset to recover.
> 
> Is it the same thing to disallow PRI for VF in IOMMUFD?
> 

yes