On Fri, 11 Feb 2011 02:41:35 +0100 Alexander Graf <ag...@suse.de> wrote:
> >> Maybe we should go with Avi's proposal after all and simply keep the full > >> soft-mmu synced between kernel and user space? That way we only need a > >> setup call at first, no copying in between and simply update the user > >> space version whenever something changes in the guest. We need to store > >> the TLB's contents off somewhere anyways, so all we need is an additional > >> in-kernel array with internal translation data, but that can be separate > >> from the guest visible data, right? Hmm, the idea is growing on me. > So then everything we need to get all the functionality we need is a hint > from kernel to user space that something changed and vice versa. > > From kernel to user space is simple. We can just document that after every > RUN, all fields can be modified. > From user space to kernel, we could modify the entries directly and then pass > in an ioctl that passes in a dirty bitmap to kernel space. KVM can then > decide what to do with it. I guess the easiest implementation for now would > be to ignore the bitmap and simply flush the shadow tlb. > > That gives us the flush almost for free. All we need to do is set the tlb to > all zeros (should be done by env init anyways) and pass in the "something > changed" call. KVM can then decide to simply drop all of its shadow state or > loop through every shadow entry and flush it individually. Maybe we should > give a hint on the amount of flushes, so KVM can implement some threshold. OK. We'll also need a config ioctl to specify MMU type/size and the address of the arrays. > Also, please tell me you didn't implement the previous revisions already. I didn't. :-) -Scott
