On 12/22/2011 02:49 PM, Christian Borntraeger wrote: > > Interesting. Other archs emulate everything to do with registers in the > > kernel, so this is not a fast path. > > > > What workload does this benefit? > > My main concern was the prefix register (this is a per cpu register that > defines the address of two pages that are swapped with the pages at 0 for this cpu). > SMP on s390 is done that way (e.g. interrupt things are stored in page 0 for this cpu) > The storage that qemu sees is storage without prefix. For architecture compliance > we actually must check _every_ memory access if it hits the prefix/swpa area and > the add/subtract the prefix value. Those are only memory accesses coming from the cpu, yes? Why does userspace have to access them at all? I imagine DMA ignores it completely since it doesn't come from the cpu. > I just added the ability to share other registers later after some discussions > with Alexander Graf because it seems to be doable for almost no cost. I doubt other archs will benefit, but it makes sense to reserve the space generically as you did. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
