Re: [PATCH 5/5] KVM: assigned dev: MSI-X mask support

[Marcelo Tosatti <mtosatti@redhat.com>]

On Fri, Nov 05, 2010 at 06:53:50PM +0800, Sheng Yang wrote:
> On Friday 05 November 2010 16:43:33 Michael S. Tsirkin wrote:
> > On Fri, Nov 05, 2010 at 10:44:19AM +0800, Sheng Yang wrote:
> > > > > +};
> > > > > +
> > > > > +This ioctl would enable in-kernel MSI-X emulation, which would
> > > > > handle MSI-X +mask bit in the kernel.
> > > > 
> > > > What happens on repeated calls when it's already enabled?
> > > > How does one disable after it's enabled?
> > > 
> > > Suppose this should only be called once. But again would update the MMIO
> > > base.
> > 
> > So maybe add this all to documentation.
> > 
> > > It
> > > would be disabled along with device deassignment.
> > 
> > So what are you going to do when guest enables and later disables MSIX?
> > Disable assignment completely?
> 
> This device goes with PCI resources allocation, rather than IRQ assignment.

What about hot plug, for example? I can't see how this can function
without unregistering regions.