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
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 -- 2.34.1
