Re: [PATCH] vfio/migrate: Move switch of dirty tracking into vfio_memory_listener

[Alex Williamson <alex.williamson@redhat.com>]

On Fri, 29 Jan 2021 08:49:53 +0100
Paolo Bonzini <pbonzini@redhat.com> wrote:

> On 28/01/21 21:02, Dr. David Alan Gilbert wrote:
> > * Paolo Bonzini (pbonzini@redhat.com) wrote:  
> >> On 11/01/21 08:34, Keqian Zhu wrote:  
> >>> +static void vfio_listener_log_start(MemoryListener *listener,
> >>> +                                    MemoryRegionSection *section,
> >>> +                                    int old, int new)
> >>> +{
> >>> +    VFIOContainer *container = container_of(listener, VFIOContainer, listener);
> >>> +
> >>> +    vfio_set_dirty_page_tracking(container, true);
> >>> +}  
> >>
> >> This would enable dirty page tracking also just for having a framebuffer
> >> (DIRTY_MEMORY_VGA).  Technically it would be correct, but it would also be
> >> more heavyweight than expected.  
> > 
> > Wouldn't that only happen on emulated video devices?  
> 
> Yes, but still it's not impossible to have both an emulated VGA and an 
> assigned GPU or vGPU.

In fact, that's often the recommended configuration, particularly for
vGPU where we don't have a vBIOS.  Thanks,

Alex