On Thu, Mar 31, 2011 at 02:29:50PM -0500, Anthony Liguori wrote: > On 03/31/2011 02:18 PM, Peter Maydell wrote: > >On 31 March 2011 20:01, Anthony Liguori<anth...@codemonkey.ws> wrote: > >>VGA is just another device. It happens to be that we treat VGA device > >>memory as something that behaves like ram occassionally but that does not > >>make it RAM. > >So, to ask a dumb question, what does make something RAM? > > It's a made up concept that we use to make device performance faster. > > Basically, RAM should include all of the memory that a reasonable > device (that we control) would DMA to and has a relatively stable > mapping. > > >My take on RAM is that RAM is just another device; the only > >difference is that you want to be able to implement fast > >paths that go straight(ish) to target memory; but that's > >an optimisation detail, not something that makes RAM > >conceptually different from other devices... > > Right, the trouble is, if you want to treat RAM like any other > device, you can't get stable mappings to it which is bad for > something like vhost-net. > > Regards, > > Anthony Liguori
Not only that I guess. Removing the VGA memory with the baloon will likely also be a bad idea. -- MST
