Re: [Xen-devel] [PATCH 4/4] xen: Always set the vram dirty during migration.

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On 17/07/12 19:30, Stefano Stabellini wrote:
> On Tue, 17 Jul 2012, Stefano Stabellini wrote:
> > On Tue, 17 Jul 2012, Anthony PERARD wrote:
> > > Because the call to track the dirty bit in the video ram during migration won't
> > > work (it returns -1), we set dirtybit on the all video ram.
> > >
> > > Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> > > ---
> > >   xen-all.c |    5 +++++
> > >   1 files changed, 5 insertions(+), 0 deletions(-)
> > >
> > > diff --git a/xen-all.c b/xen-all.c
> > > index 498883b..00bdb50 100644
> > > --- a/xen-all.c
> > > +++ b/xen-all.c
> > > @@ -502,6 +502,11 @@ static void xen_sync_dirty_bitmap(XenIOState *state,
> > >           return;
> > >       }
> > >
> > > +    if (unlikely(xen_in_migration)) {
> > > +        /* track_dirty_vram does not work during migration */
> > > +        memory_region_set_dirty(framebuffer, 0, size);
> > > +        return;
> > > +    }
> > >       rc = xc_hvm_track_dirty_vram(xen_xc, xen_domid,
> > >                                    start_addr >> TARGET_PAGE_BITS, npages,
> > >                                    bitmap);
> > Why are you setting the entire framebuffer dirty?
> > We should set dirty only the actualy region that is supposed to be
> > dirty.
I set the dirty bit on the all framebuffer because the track dirty call 
fail, so I don't which bits are dirty. This one is for QEMU to know 
which part of the screen need to be updated.
> Also memory_region_set_dirty calls cpu_physical_memory_set_dirty_range,
> in which you didn't add a call to xen_modified_memory.


--
Anthony PERARD

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