On 01/23/2012 07:18 PM, Anthony Liguori wrote: > Generally speaking, RAM is an independent device in most useful cases.
Can you give examples? Do you mean a subdevice with composition, or a really independent device? > Onboard RAM is a very special case because it's extremely unusual. What's unusual (or even extremely unusual) about it? I don't see a difference between a few billion bits of state and, say, the few bits of state in an RTC device. > But since some video cards can make use of dedicated external RAM, I > don't think any video card really depends on initial RAM state. > > What's most likely here is that the VGA BIOS of a Cirrus card sets an > initial RAM state during device initialization. Yes, that's likely. DRAMs aren't reset and some state survives even a short power off. > > We really should view RAM as just another device so I don't like the > idea of propagating a global concept of "when RAM is restored" because > that treats it specially compared to other devices. Agree. In fact the first step has been taken as now creating a RAM region with memory_region_init_ram() doesn't register it for migration. The next step would be a VMSTATE_RAM() to make it part of the containing device. > But viewing RAM as just another device, having Xen only restore a > subset of devices should be a reasonable thing to do moving forward. > The main problem here I believe is that we have part of the VGA Bios > functionality in the hardware emulation. Doesn't the main BIOS clear the screen first thing at boot? Not even sure the reset is needed. -- error compiling committee.c: too many arguments to function
