Avi Kivity wrote: > Nakajima, Jun wrote: > > An updated specification (Rev 1.0 update) of Intel(r) virtualization > > technology for Directed I/O is now available on Intel web site: > > > > http://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Di > > rect_IO.pdf > > > > The specification update includes DMA remapping capability, Interrupt > > remapping capability, queue management, invalidation information and > > enhancements. > > > > We are thinking how this should be enabled for KVM as well especially > > when assigning real devices to guests. Suggestions are welcome. > > > > I've had a quick look-see. There are two general approaches which I > think make sense: > > - tightly coupled kvm integration, where kvm is extended with a > root-only 'assign pci dev x to this vm'. As the page table format is > the same as used by ept (I'm guessing... haven't actually read the ept > spec), this should be quite easy to do on once npt/ept support is > integrated.
I agree that it's straightforward to handle those page tables. The question is interrupt remapping, i.e. how to inject particular external interupts to the vm that is reposible for the interrupts without impacting the kernel code. We are considering the irq chip infrastrure. > > - general interface for manipulating VT-d, with the ability to use it > with kvm. With this, it is possible to assign pci devices to ordinary > userspace processes, some of which could be hosting virtual machines. > This may fit will with the UIO patchset. > > Unless I misread things, VT-d does not honor the U/S bit on the page > table entries. That makes the general approach fairly difficult. I > would recommend starting with the tightly-coupled, less generic approach > first, and generalizing it if/when there is demand for it. I agree that we should start with the tightly-coupled. Jun --- Intel Open Source Technology Center ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
