On 07/25/2012 01:53 PM, Benjamin Herrenschmidt wrote: > On Wed, 2012-07-25 at 13:27 +0300, Avi Kivity wrote: >> On 07/25/2012 06:57 AM, Benjamin Herrenschmidt wrote: >> > Hi folks ! >> > >> > Would there be any objection to adding a second MMIO BAR to qemu-vga >> > which mirrors the bochs magic VBE ports ? >> > >> > Support for IO space is optional in PCIe and can be problematic on some >> > architectures, it would be nice to be able to program the card entirely >> > using mmio. >> >> Can we choose a PCIe chipset that does support IO space? > > Why bother ? It's not like mode setting is performance critical and IO > space is always going to be a pain on non-x86 ...
For compatibility? If it's a special pain, then I understand, but what's the difference between emulating chipset A or B? > >> If not, we can add a second BAR, but it should disappear when running an >> older machine type. > > Well, the IO ports in legacy space are still there. We can also make the > "register BAR" exist in both mode or we can add a second BAR and have > x86 "prefer" IO... whatever rocks your boat as long as it's a BAR, it's > the legacy hole that's annoying for me :-) A guest created with -M old must look exactly the same as it did in an older version of qemu, no extra BARs. -- error compiling committee.c: too many arguments to function
