On Tue, Oct 25, 2022 at 08:47:33PM -0400, Gregory Price wrote: > Submitted as an extention to the multi-feature branch maintained > by Jonathan Cameron at: > https://urldefense.com/v3/__https://gitlab.com/jic23/qemu/-/tree/cxl-2022-10-24__;!!EwVzqGoTKBqv-0DWAJBm!RyiGL5B1XmQnVFwgxikKJeosPMKtoO1cTr61gIq8fwqfju8l4cbGZGwAEkKXIJB-Dbkfi_LNN2rGCbzMISz65cTxpAxI9pQ$ > > > > Summary of Changes: > 1) E820 CFMW Bug fix. > 2) Add CXL_CAPACITY_MULTIPLIER definition to replace magic numbers > 3) Multi-Region and Volatile Memory support for CXL Type-3 Devices > 4) CXL Type-3 SRAT Generation when NUMA node is attached to memdev > > > Regarding the E820 fix > * This bugfix is required for memory regions to work on x86 > * input from Dan Williams and others suggest that E820 entry for > the CFMW should not exist, as it is expected to be dynamically > assigned at runtime. If this entry exists, it instead blocks > region creation by nature of the memory region being marked as > reserved.
For CXL 2.0 it is my understanding that volatile capacity present at boot will be advertised by the firmware. In the absence of EFI I would assume this would be provided in the e820 map. Is the region driver meant to cover volatile capacity present at boot? I was under the impression that it would be used for hot added volatile memory. It would be good to cover all of these assumptions for the e820 fix. Lastly it is my understanding that the region driver does not have support for volatile memory. It would be great to add that functionality if we make this change in QEMU. > > Regarding Multi-Region and Volatile Memory > * Developed with input from Jonathan Cameron and Davidlohr Bueso. > > Regarding SRAT Generation for Type-3 Devices > * Co-Developed by Davidlohr Bueso. Built from his base patch and > extended to work with both volatile and persistent regions. > * This can be used to demonstrate static type-3 device mapping and > testing numa-access to type-3 device memory regions. > > > This series brings 3 features to CXL Type-3 Devices: > 1) Volatile Memory Region support > 2) Multi-Region support (1 Volatile, 1 Persistent) > 3) (optional) SRAT Entry generation for type-3 device regions > > In this series we implement multi-region and volatile region support > through 7 major changes to CXL devices > 1) The HostMemoryBackend [hostmem] has been replaced by two > [hostvmem] and [hostpmem] to store volatile and persistent > memory respectively > 2) The single AddressSpace has been replaced by two AddressSpaces > [hostvmem_as] and [hostpmem_as] to map respective memdevs. > 3) Each memory region size and total region are stored separately > 4) The CDAT and DVSEC memory map entries have been updated: > a) if vmem is present, vmem is mapped at DPA(0) > b) if pmem is present > i) and vmem is present, pmem is mapped at DPA(vmem->size) > ii) else, pmem is mapped at DPA(0) > c) partitioning of pmem is not supported in this patch set but > has been discussed and this design should suffice. > 5) Read/Write functions have been updated to access AddressSpaces > according to the mapping described in #4 > 6) cxl-mailbox has been updated to report the respective size of > volatile and persistent memory regions > 7) SRAT entries may optionally be generated by manually assigning > memdevs to a cpuless numa node > > To support the Device Physical Address (DPA) Mapping decisions, see > CXL Spec (3.0) Section 8.2.9.8.2.0 - Get Partition Info: > Active Volatile Memory > The device shall provide this volatile capacity starting at DPA 0 > Active Persistent Memory > The device shall provide this persistent capacity starting at the > DPA immediately following the volatile capacity > > Partitioning of Persistent Memory regions may be supported on > following patch sets. > > > Gregory Price (4): > hw/i386/pc.c: CXL Fixed Memory Window should not reserve e820 in bios > hw/cxl: Add CXL_CAPACITY_MULTIPLIER definition > hw/cxl: Multi-Region CXL Type-3 Devices (Volatile and Persistent) > hw/acpi/cxl.c: Fill in SRAT for vmem/pmem if NUMA node is assigned > > docs/system/devices/cxl.rst | 74 ++++++++-- > hw/acpi/cxl.c | 67 +++++++++ > hw/cxl/cxl-mailbox-utils.c | 23 +-- > hw/i386/acpi-build.c | 4 + > hw/i386/pc.c | 2 - > hw/mem/cxl_type3.c | 274 +++++++++++++++++++++++++++--------- > include/hw/acpi/cxl.h | 1 + > include/hw/cxl/cxl_device.h | 11 +- > tests/qtest/cxl-test.c | 111 +++++++++++---- > 9 files changed, 443 insertions(+), 124 deletions(-) > > -- > 2.37.3 >
