Re: [Xen-devel] [PATCH] Don't track all memory when enabling log dirty to track vram

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.05.14 at 05:13, <yang.z.zhang@xxxxxxxxx> wrote:
> George Dunlap wrote on 2014-05-19:
>> Avoiding these by "hoping" that the guest OS doesn't DMA into a video
>> buffer isn't really robust enough.  I think that was Tim and Jan's
> 
> Video buffer is only one case. How we can prevent the DMA to other reserved 
> region?

You continue to neglect the difference: Accessing VRAM this way is
legitimate (and potentially useful). And - as just said in the other
reply - ideally we'd also simply ignore accesses to reserved regions
(and in fact we try to, by not immediately bringing down a guest
device doing such).

Jan


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