On Mon, Jan 31, 2011 at 03:24:27PM +0200, Avi Kivity wrote: > On 01/26/2011 11:05 AM, Sheng Yang wrote: > >On Tuesday 25 January 2011 20:47:38 Avi Kivity wrote: > >> On 01/19/2011 10:21 AM, Sheng Yang wrote: > >> > > > We already got an guest MMIO address for that in the exit > >> > > > information. I've created a chain of handler in qemu to handle it. > >> > > > >> > > But we already decoded the table and entry... > >> > > >> > But the handler is still wrapped by vcpu_mmio_write(), as a part of MMIO. > >> > So it's not quite handy to get the table and entry out. > >> > >> The kernel handler can create a new kvm_run exit description. > >> > >> > Also the updater in the userspace > >> > > >> > can share the most logic with ordinary userspace MMIO handler, which take > >> > address as parameter. So I think we don't need to pass the decoded > >> > table_id and entry to userspace. > >> > >> It's mixing layers, which always leads to trouble. For one, the user > >> handler shouldn't do anything with the write since the kernel already > >> wrote it into the table. For another, if two vcpus write to the same > >> entry simultaneously, you could see different ordering in the kernel and > >> userspace, and get inconsistent results. > > > >The shared logic is not about writing, but about interpret what's written. Old > >MMIO handler would write the data, then interpret it; and our new MMIO would only > >share the logic of interpretation. I think that's fair enough? > > It dosn't make sense for an API point of view. You registered a > table of entries, you expect an exit on that table to point to the > table and entry that got changed. OK, I would update this when I come back to work(about two weeks later...). -- regards Yang, Sheng > > -- > 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
