On Wed, 17 May 2017 02:48:00 +0200 Dong Jia Shi <bjsdjshi@xxxxxxxxxxxxxxxxxx> wrote: > The patch series introduce a basic channel I/O passthrough > infrastructure based on vfio. > - Focus on supporting dasd-eckd(cu_type/dev_type = 0x3990/0x3390) as > the target device. > - Support new qemu parameters in the style of: > -machine s390-ccw-virtio(,s390-squash-mcss=on|off) \ > -device vfio-ccw,sysfsdev=$MDEV_PATH > We want to support real (i.e. not virtual) channel devices even for > guests that do not support MCSS-E (where guests may see devices from > any channel subsystem image at once). As all virtio-ccw devices are in > css 0xfe (and show up in the default css 0 for guests not activating > MCSS-E), we need an option to squash e.g. passed-through channel devices > from their real css (0-3, or 0 for hosts not activating MCSS-E) into > the default css, that is what the new machine option s390-squash-css is > added. Patches queued, with minor changes (see my comments). I'll push out to s390-next once this passes some of my tests. > > Build and install: > 1. kernel configuration > CONFIG_S390_CCW_IOMMU=m > CONFIG_VFIO=m > CONFIG_VFIO_MDEV=m > CONFIG_VFIO_MDEV_DEVICE=m > CONFIG_VFIO_CCW=m > 2. modules required > modprobe vfio.ko > modprobe mdev.ko > modprobe vfio_mdev.ko > modprobe vfio_iommu_type1.ko > modprobe vfio_ccw.ko > 3. find a subchannel(0.0."%schid") of a DASD-ECKD device and bind it to > vfio_ccw driver > #find the dasd you can use with lsdasd on your host. e.g.: > devno="7e52" > schid="16ca" > #unbind the ccw device from the subchannel > echo 0.0."$devno" > /sys/bus/ccw/devices/0.0."$devno"/driver/unbind > #unbind the subchannel from io_subchannel driver > echo 0.0."$schid" > /sys/bus/css/devices/0.0."$schid"/driver/unbind > #bind the subchannel with vfio_ccw driver > echo 0.0."$schid" > /sys/bus/css/drivers/vfio_ccw/bind > 4. create a mediated device > #generate a uuid with uuidgen. e.g.: > uuid="6dfd3ec5-e8b3-4e18-a6fe-57bc9eceb920" > echo "$uuid" > \ > /sys/bus/css/devices/0.0."$schid"/mdev_supported_types/vfio_ccw-io/create > 5. pass-through this device to a vm > -M s390-ccw-virtio,s390-squash-css=on \ > -device vfio-ccw,sysfsdev=/sys/bus/mdev/devices/$uuid \ > ... ... These instructions would be helpful to preserve in the qemu wiki and could even be expanded upon. Ping me if you need an account (hint, hint ;) -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
