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

[Anthony PERARD <anthony.perard@citrix.com>]

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@citrix.com>
>>> ---
>>>   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