RFC because - Many contents are ported from Jonathan' patch on qemu virt design
- Bring plenty of PCDs values and modifying the original PCIE values
- Less experience and not particularly confident in ACPI area so this might be stupidly broken in a way I've not considered.
Currently the base CXL support for arm platforms is only on Jonathan's patches[1] which have not yet merged into upstream. SBSA-REF can be more like a real machine, thus the support of cxl could be meaningful.
Regard to the burden of edk2 firmware, I try to build a static CEDT table and add acpi0016, acpi0017 objects on DSDT at the initial development phase[2][3]. Hence it doesn't need to communicate cxl contents via DT to edk2.
This series leverages Jonathan's patches[1] to design [SBSA_CXL_HOST] and [SBSA_CXL_FIXED_WINDOW] spaces for sbsa-ref layout.
For [SBSA_CXL_HOST], new memory layout places 1M space for 16 host bridge register regions in the sbsa-ref memmap. In addition, this only creates a default pxb-cxl (bus_nr=0xfe) bridge with one cxl-rp on sbsa-ref, so only one cxl device could be added by user on this cxl Bus. With the 'create_pxb_cxl', users don't need to input '-device pxb-cxl' and '-device cxl-rp' parameters.
For [SBSA_CXL_FIXED_WINDOW], this extends 1TB space from the hole above RAM Memory [SBSA_MEM] for CXL Fixed Memory Window. 0xA0000000000 is chosen as the base address of this space because of 3 reasons:
1) It is more suitable to choose a static address instead of that implementation in virt, since a dynamic address space layout of sbsa-ref is not appropriate for its original purpose as a reference platform.
2) The Hotplug Memory address range should in the range of maximum addressable range of sbsa-ref platform(0x10000000000-0x80ffffffffff). It is satisfied the requirements of memory hotplug in linux kernel.
3) The start pfn of CFMW should exceed the reserved_pfn_range for onlined numa node.
Based on 'cxl_fmws_link_targets', this adds a new function 'sbsa_cxl_fmws_link_targets' for binding cfmws.target with the default pxb-cxl-bus on sbsa-ref.
In addition, this also adds 'create_cxl_fixed_window_region' which based on 'machine_set_cfmw' to support creating a static cfmw region on sbsa-ref, so users don't need to input '-M cxl-fmw' parameter.
Thus, to run sbsa-ref with a cxl device could use: qemu-system-aarch64 \ -machine sbsa-ref \ -cpu cortex-a57 \ -smp 4 \ -m 4G \ -object memory-backend-ram,size=2G,id=mem0 \ -numa node,nodeid=0,cpus=0-1,memdev=mem0 \ -object memory-backend-ram,size=2G,id=mem1 \ -numa node,nodeid=1,cpus=2-3,memdev=mem1 \ -object memory-backend-file,id=mem2,mem-path=/tmp/mem2,size=256M,share=true \ -device cxl-type3,bus=cxl.0,volatile-memdev=mem2,id=cxl-mem1 \ -hda ubuntu.ext4 \ -pflash SBSA_FLASH0.fd \ -pflash SBSA_FLASH1.fd \
This series patches are here to hopefully some comments to guide me!
Link: [1]: https://lore.kernel.org/linux-cxl/20220616141950.23374-1-Jonathan.Cameron@hu... [2]: https://edk2.groups.io/g/devel/topic/rfc_patch_0_1/108173029 [3]: https://edk2.groups.io/g/devel/topic/rfc_patch_edk2_platforms/108173682
Yuquan Wang (2): hw/arm/sbsa-ref: Enable CXL Host Bridge by pxb-cxl hw/arm/sbsa-ref: Support CXL Fixed Memory Window
hw/arm/sbsa-ref.c | 127 +++++++++++++++++++++++++++- hw/cxl/cxl-host-stubs.c | 1 + hw/cxl/cxl-host.c | 2 +- hw/pci-bridge/pci_expander_bridge.c | 1 - include/hw/cxl/cxl_host.h | 1 + include/hw/pci/pci_bridge.h | 1 + 6 files changed, 128 insertions(+), 5 deletions(-)