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-map-css=on|off) ...
-device vfio-ccw,id=xx,hostid=xx(,guestid=xx)".
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 map 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-map-css is
added.
- According to the user-space ccw format, which was introduced by the
vfio-ccw patches of the kernel part, assemble the ccw program in qemu.
This 'ccw program' would then be transported to the kernel via a
dedicated ioctl for further processing(e.g. translation in kernel
space), and issuing it to the real device.
Overview of the user-space ccw translation(translate 'guest ccw
program' to 'user-space ccw program'):
1. Allocate a 4K memory buffer in user-space to store all of the ccw
program information.
* Lower 2k of the buffer are used to store a maximum of 256 ccws.
These ccws are copied from 'guest ccw program' and placed one
after another.
* Upper 2k of the buffer are used to store a maximum of 256
corresponding cda data sets, each having a length of 8 bytes.
2. For TIC ccw.
* Locate the TIC target ccw inside the ccw area, and calculate its
offset.
* Store the offset to ccw.cda.
3. For Direct ccw.
* Find the cda entry with the same index as the ccw.
* Store the user virtual address of the original ccw.cda to the cda
entry.
* Store the offset of the cda entry to ccw.cda.
4. For IDAL ccw.
* Find the cda entry with the same index as the ccw.
* Prepare the user-space idaws. Store the virtual address of the
idaws to the cda entry.
* Store the offset of the cda entry to ccw.cda.
5. Append a NOOP to the chain end.
6. Expectations for the user-space ccw program I/O result:
CPA of SCSW should be set to the offset of the ccw area of the
current ccw.
Xiao Feng Ren (9):
vfio: linux-headers update for vfio-ccw
vfio: No-IOMMU mode support
s390x/css: introduce ccw chain interfaces
s390x/css: add s390-map-css machine option
s390x/css: realize css_sch_build_schib
s390x/css: device and bus support for s390-ccw passthrough
vfio/ccw: vfio based ccw passthrough driver
s390x/css: introduce and realize ccw-request callback
s390x/css: ccws translation infrastructure
default-configs/s390x-softmmu.mak | 1 +
hw/s390x/Makefile.objs | 1 +
hw/s390x/css.c | 283 ++++++++++++++++++++++--
hw/s390x/css.h | 12 +
hw/s390x/s390-ccw-bus.c | 114 ++++++++++
hw/s390x/s390-ccw-bus.h | 30 +++
hw/s390x/s390-ccw.c | 189 ++++++++++++++++
hw/s390x/s390-ccw.h | 41 ++++
hw/s390x/s390-ccwchain.c | 441 +++++++++++++++++++++++++++++++++++++
hw/s390x/s390-ccwchain.h | 28 +++
hw/s390x/s390-virtio-ccw.c | 26 +++
hw/s390x/virtio-ccw.c | 1 +
hw/s390x/virtio-ccw.h | 2 -
hw/vfio/Makefile.objs | 1 +
hw/vfio/ccw.c | 230 +++++++++++++++++++
hw/vfio/common.c | 66 ++++--
include/hw/s390x/s390-virtio-ccw.h | 1 +
include/hw/vfio/vfio-common.h | 3 +
linux-headers/linux/vfio.h | 32 +++
qemu-options.hx | 6 +-
target-s390x/cpu.h | 10 +
target-s390x/ioinst.c | 9 +
22 files changed, 1493 insertions(+), 34 deletions(-)
create mode 100644 hw/s390x/s390-ccw-bus.c
create mode 100644 hw/s390x/s390-ccw-bus.h
create mode 100644 hw/s390x/s390-ccw.c
create mode 100644 hw/s390x/s390-ccw.h
create mode 100644 hw/s390x/s390-ccwchain.c
create mode 100644 hw/s390x/s390-ccwchain.h
create mode 100644 hw/vfio/ccw.c
--
2.6.6
--
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
