Hello,
On 5/18/23 04:45, Ira Weiny wrote:
Type 2 devices are not yet a reality. Developing core kernel support
is difficult without some test device to model against.
Define a type 2 device 'cxl-accel'. This device is derived from the
type 3 device and retains all that functionality for now.
Mock up a couple of accelerator features (Back Invalidate [BI] and
Unordered IO [UIO]) as examples for the RFC. These have no
functionality other than to report the features as present for software
to key off of.
Defining these devices in qemu can be done with the following example:
...
-device
cxl-accel,bus=sw0p0,volatile-memdev=cxl-ac-mem5,id=cxl-dev5,sn=0xCAFE0005
...
NOTE: I'm leaving off Michael Tsirkin for now because this is really
rough and I'm mainly sending it out because it was talked about in the
CXL community call on 5/16.
Not-Yet-Signed-off-by: Ira Weiny <ira.we...@intel.com>
A recent proposal to add support in VFIO for CXL passthrough uses
this emulated device and a sample driver for a proof of concept.
For this effort, it would be very useful to have a QEMU model for
a CXL type2 device, even partially implemented.
I haven't found any updates of this series. What are the plans for
upstream today ?
For vfio-cxl, see :
* [RFC] vfio: introduce vfio-cxl to support CXL type-2 accelerator passthrough
https://lore.kernel.org/kvm/20240920223446.1908673-1-z...@nvidia.com
* [RFC] Introduce vfio-cxl to support CXL type-2 device passthrough
https://lore.kernel.org/all/20240921071440.1915876-1-z...@nvidia.com/
Thanks,
C.
---
Ira Weiny (5):
hw/cxl: Use define for build bug detection
hw/cxl: Refactor component register initialization
hw/cxl: Derive a CXL accelerator device from Type-3
hw/cxl/accel: Add Back-Invalidate decoder capbility structure
hw/cxl: Add UIO HDM decoder register fields
docs/system/devices/cxl.rst | 11 ++++++
hw/cxl/cxl-component-utils.c | 80 +++++++++++++++++++-----------------------
hw/mem/cxl_type3.c | 39 ++++++++++++++++++++
include/hw/cxl/cxl_component.h | 51 +++++++++++++++++++--------
include/hw/cxl/cxl_device.h | 16 +++++++++
include/hw/pci/pci_ids.h | 1 +
6 files changed, 141 insertions(+), 57 deletions(-)
---
base-commit: 8eb2a03258313f404ca0c8609a8f9009b9b4318c
change-id: 20230517-rfc-type2-dev-c2d661a29d96
Best regards,
