[RFC,0/1] Introduce vfio-cxl to support CXL type-2 device passthrough

Message

Zhi Wang Sept. 21, 2024, 7:14 a.m. UTC

Compute Express Link (CXL) is an open standard interconnect built upon
industrial PCI layers to enhance the performance and efficiency of data
centers by enabling high-speed, low-latency communication between CPUs
and various types of devices such as accelerators, memory.

Although CXL is built upon the PCI layers, passing a CXL type-2 device can
be different than PCI devices according to CXL specification. Thus,
addtional changes on are required.

vfio-cxl is introduced to support the CXL type-2 device passthrough.
This is the QEMU VFIOStub draft changes to support it.

More details (patches, repos, kernel config) all what you need to test
and hack around, plus a demo video shows the kernel/QEMU command line
can be found at:
https://lore.kernel.org/kvm/[e-mail]/T/

Zhi Wang (1):
  vfio: support CXL device in VFIO stub

 hw/vfio/common.c              |   3 +
 hw/vfio/pci.c                 | 134 ++++++++++++++++++++++++++++++++++
 hw/vfio/pci.h                 |  10 +++
 include/hw/pci/pci.h          |   2 +
 include/hw/vfio/vfio-common.h |   1 +
 linux-headers/linux/vfio.h    |  14 ++++
 6 files changed, 164 insertions(+)

Comments

Cédric Le Goater Sept. 26, 2024, 4:52 p.m. UTC | #1

Hello Zhi,

On 9/21/24 09:14, Zhi Wang wrote:
> Compute Express Link (CXL) is an open standard interconnect built upon
> industrial PCI layers to enhance the performance and efficiency of data
> centers by enabling high-speed, low-latency communication between CPUs
> and various types of devices such as accelerators, memory.
> 
> Although CXL is built upon the PCI layers, passing a CXL type-2 device can
> be different than PCI devices according to CXL specification. Thus,
> addtional changes on are required.
> 
> vfio-cxl is introduced to support the CXL type-2 device passthrough.
> This is the QEMU VFIOStub draft changes to support it.
> 
> More details (patches, repos, kernel config) all what you need to test
> and hack around, plus a demo video shows the kernel/QEMU command line
> can be found at:
> https://lore.kernel.org/kvm/[e-mail]/T/


I have started looking at the software stack and the QEMU trees
are quite old. Could you please rebase the branches on the latest ?

Also, I think having a single branch per project would be easier.

For linux :
   [v2] cxl: add Type2 device support
   [RFC] vfio: introduce vfio-cxl to support CXL type-2
   [RFC] samples: introduce QEMU CXL accel driver

Same for QEMU.

Thanks,

C.



> 
> Zhi Wang (1):
>    vfio: support CXL device in VFIO stub
> 
>   hw/vfio/common.c              |   3 +
>   hw/vfio/pci.c                 | 134 ++++++++++++++++++++++++++++++++++
>   hw/vfio/pci.h                 |  10 +++
>   include/hw/pci/pci.h          |   2 +
>   include/hw/vfio/vfio-common.h |   1 +
>   linux-headers/linux/vfio.h    |  14 ++++
>   6 files changed, 164 insertions(+)
>