Avi Kivity wrote: > On 03/08/2010 10:19 PM, Michael Tokarev wrote: >> Michael Tokarev wrote: >> [] >> >>> Apparently that does not quite work. I just re-compiled kvm with >>> --enable-linux-aio (actually I just installed libaio-dev on debian >>> and qemu-kvm's configure picked it up automatically), and tried >>> a guest. But any I/O fails. >>> >> It has nothing to do with kvm. It is compat_ioctl32 in the kernel >> wrt aio calls. Historically I've a 64bit kernel with 32bit userland, >> and tried 32bit kvm too, and that does not work. But 64bit kvm works >> just fine with aio, and the performance numbers are indeed better. > > Can you elaborate? This sounds like a bug that wants to be fixed. http://thread.gmane.org/gmane.linux.kernel.aio.general/2891 It's missing compat_ioctl for some of the aio opcodes, namely it's PREADV and PWRITE - the only ones used by kvm and the only ones missing in kernel. As far as i can see, current code converts the iocb array just fine, but does not touch iovec array used with p{read,write}v. /mjt -- 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
