On Sun, 2007-09-30 at 10:15 +0300, Blue Swirl wrote: > On 9/30/07, J. Mayer <[EMAIL PROTECTED]> wrote: > > On Sat, 2007-09-29 at 23:43 +0100, Paul Brook wrote: > > > > > Also note that changing variables from int to long have strictly no > > > > > impact on 32 bits host machines, then won't help emulating more than 2 > > > > > GB of RAM. Another variable type (target_phys_addr_t ?) should be used > > > > > instead. > > > > > > > > This patch should be restricted to 64-bit hosts. I don't think it's > > > > useful to emulate a 64-bit target with huge amounts of virtual and > > > > physical address space on a 32-bit host. > > > > My feeling is that if it's restricted to 64 bits host, then it's a patch > > for geeks only, that brings no useful feature to the main end-users. In > > the real world, most people are still running in 32 bits mode. > > I think Qemu is a geek application. The majority of people with their > i386 Windows PCs don't know or care about, for example Sparc32 > targets, or even about Qemu. The people who know about Qemu are > probably geeks, they already have some kind of need to emulate > hardware. I'd think majority of them still want to emulate an i386 > target on their i386/x86_64 host. Other targets and hosts are a > minority, making the people interested in those even geekier. > > But whether this patch or something else is a geek feature or not is > irrelevant. What matters is whether it breaks something or not, or if > some part of the design is objectionable. I fully agree with you that > some parts could be designed differently.
About the design, my opinion is: - to support wider physical address spaces: * full 32 bits targets (ie 32 bits virtual & physical address spaces) should stay 32 bits. * for 32 bits targets with a few more bits for their physical address space (like the ppcemb target, which has 36 bits of physical address space and I guess x86 with PAE extension), it seems acceptable to only adjust the L1_BITS constants. * for 64 bits targets, a multiple level table has to be used to avoid the need of huge l1_xxx tables. This includes the alpha target (42 bits of physical address space), for which I recognize the quick hack I did commit is not really acceptable. - to support more than 2 GB of RAM: I still think you should have to use a consistent type here, not just unsigned long. Do you really need another new type ? It seems to me that one of physical_addr_t or ram_addr_t could be used ? -- J. Mayer <[EMAIL PROTECTED]> Never organized