On 6/16/25 9:06 PM, wangyuquan wrote: > v2 -> v3: > - Update the commit message > - Fix some alignment and space problems > - Add a SPDX header for the new file > - Remove unnecessary comments > - Add CXL_HOST_BRIDGE config > v1 -> v2: > - Move the code of new bridge to hw/pci-host/cxl.c > - Fix and simplify some logic on handling the different bridge types Hi Yuquan, can you please add qemu to your patch subject prefix in the future? i.e. [QEMU PATCH v4 0/2]. It would help the maintainers on linux-cxl to know they are not kernel patches. Thank you! > > Background > ========== > Currently the base CXL support for arm platforms is only on Jonathan's > patches[1]. Some platform like SBSA-REF can be more like a real machine, > thus the support of CXL could be meaningful. However, the pxb-cxl-host > realization on this platform seems not satisfying their requirements[2]. > > New CXL HOST design > =================== > Defines a new CXL host bridge type (TYPE_CXL_HOST). This is an > independent CXL host bridge which combined GPEX features (ECAM, MMIO > windows and irq) and CXL Host Bridge Component Registers (CHBCR). > > The root bus path of CXL_HOST is "0001:00", that would not affect the > original pcie host topology. In the previous, the pxb-cxl-host with > any CXL root ports and CXL endpoint devices would occupy the BDF > number of the original pcie domain. This new type provide a solution > to resolve the problem. > > Remaining problems > ================== > I tried to use 'object_resolve_path' but it could not work in > 'cxl_fmws_link_targets', so I used 'TYPE_DEVICE' to match that. > > Link: > [1]: > https://lore.kernel.org/linux-cxl/20220616141950.23374-1-jonathan.came...@huawei.com/ > [2]: https://lists.nongnu.org/archive/html/qemu-arm/2024-11/msg00522.html > > Yuquan Wang (2): > pci-host/cxl: Support creation of a new CXL Host Bridge > hw/pxb-cxl: Rename the pxb cxl host bridge > > hw/cxl/cxl-host-stubs.c | 3 + > hw/cxl/cxl-host.c | 64 ++++++++--- > hw/pci-bridge/pci_expander_bridge.c | 8 +- > hw/pci-host/Kconfig | 4 + > hw/pci-host/cxl.c | 152 ++++++++++++++++++++++++++ > hw/pci-host/meson.build | 1 + > include/hw/cxl/cxl.h | 7 +- > include/hw/cxl/cxl_host.h | 3 + > include/hw/pci-host/cxl_host_bridge.h | 23 ++++ > 9 files changed, 244 insertions(+), 21 deletions(-) > create mode 100644 hw/pci-host/cxl.c > create mode 100644 include/hw/pci-host/cxl_host_bridge.h >
