On Tue, 2007-08-21 at 22:23 -0700, Zachary Amsden wrote: > In general, I/O in a virtual guest is subject to performance problems. > The I/O can not be completed physically, but must be virtualized. This > means trapping and decoding port I/O instructions from the guest OS. > Not only is the trap for a #GP heavyweight, both in the processor and > the hypervisor (which usually has a complex #GP path), but this forces > the hypervisor to decode the individual instruction which has faulted. > Worse, even with hardware assist such as VT, the exit reason alone is > not sufficient to determine the true nature of the faulting instruction, > requiring a complex and costly instruction decode and simulation. .../... How about userland ? Things like X do IO's typically... You still need to trap/emulate for these no ? Cheers, Ben. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
