On Tue, Nov 03, 2009 at 12:24:15AM +0100, Alexander Graf wrote: >> Also, we still need to keep the local frame buffer copy in sync so we >> can mmap and read from it, right? So it's not really worth it >> probably... > > But then again we could just try to be closer to a real graphics card. > What if we'd set up a memory region on the host that is basically our > graphics frame buffer? For S390 we could just append the graphics memory > to the guest's memory. > > We could use that as backing buffer in the qemu graphics frontend and as > frame buffer in the Linux fbdev layer, similar to what real graphics > cards set up.
Using shared memory pages between host and guest seems like a natural way to implement paravirtualized graphics card. Most things are straightforward, only a little problematic thing is when fbdev is mmaped from guest to userspace - you have to detect writes and notify host that it changed. -- Elen sila lumenn' omentielvo Ondrej 'SanTiago' Zajicek (email: santi...@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
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