Re: [Qemu-devel] [RFC v4 23/58] vga: convert vga and its derivatives to the memory API

[Avi Kivity]

On 07/20/2011 05:45 PM, Jan Kiszka wrote:
> On 2011-07-20 16:40, Avi Kivity wrote:
> >  On 07/20/2011 05:05 PM, Jan Kiszka wrote:
> >>  On 2011-07-17 13:13, Avi Kivity wrote:
> >>>   Convert all vga memory to the memory API.  Note we need to fall back to
> >>>   get_system_memory(), since the various buses don't pass the vga window
> >>>   as a memory region.
> >>>
> >>
> >>>
> >>>        if (limit>   0) {
> >>>   -        /* Thinking about changing bank base? First, drop the dirty 
> bitmap information
> >>>   -         * on the current location, otherwise we lose this pointer 
> forever */
> >>>   -        if (s->vga.lfb_vram_mapped) {
> >>>   -            target_phys_addr_t base_addr = isa_mem_base + 0xa0000 + 
> bank_index * 0x8000;
> >>>   -            cpu_physical_sync_dirty_bitmap(base_addr, base_addr + 
> 0x8000);
> >>>   -        }
> >>
> >>  Why is it safe to drop this?
> >>
> >
> >  The memory API will sync the dirty bitmap once it becomes invisible.
>
> OK, maybe add a short note to the commit log in the next release?

Sure.

> >
> >  (that's the whole point - it can be made invisible by something outside
> >  the cirrus card's knowledge).
> >
> >  Note - with kvm, there is still a race between syncing the bitmap and
> >  removing the region.  However that is a bug in the kvm API; it is not
> >  possible to work around it in qemu.
> >
>
> Dirty log off, reconfigure, dirty log on?

What happens if there's a write after the first comma (assuming 
"reconfigure" == "remove slot")?

Granted, the guest shouldn't be doing that.

Hmm, I guess you could just mark the entire range dirty after removing it.

--
error compiling committee.c: too many arguments to function