On 21-08-09 15:27:47, Dan Williams wrote: > As mentioned in patch 20 in this series the response of upstream QEMU > community to CXL device emulation has been underwhelming to date. Even > if that picked up it still results in a situation where new driver > features and new test capabilities for those features are split across > multiple repositories. > > The "nfit_test" approach of mocking up platform resources via an > external test module continues to yield positive results catching > regressions early and often. Repeat that success with a "cxl_test" > module to inject custom crafted topologies and command responses into > the CXL subsystem's sysfs and ioctl UAPIs. > > The first target for cxl_test to verify is the integration of CXL with > LIBNVDIMM and the new support for the CXL namespace label + region-label > format. The first 11 patches introduce support for the new label format. > > The next 9 patches rework the CXL PCI driver and to move more common > infrastructure into the core for the unit test environment to reuse. The > largest change here is disconnecting the mailbox command processing > infrastructure from the PCI specific transport. The unit test > environment replaces the PCI transport with a custom backend with mocked > responses to command requests. > > Patch 20 introduces just enough mocked functionality for the cxl_acpi > driver to load against cxl_test resources. Patch 21 fixes the first bug > discovered by this framework, namely that HDM decoder target list maps > were not being filled out. > > Finally patches 22 and 23 introduce a cxl_test representation of memory > expander devices. In this initial implementation these memory expander > targets implement just enough command support to pass the basic driver > init sequence and enable label command passthrough to LIBNVDIMM. > > The topology of cxl_test includes: > - (4) platform fixed memory windows. One each of a x1-volatile, > x4-volatile, x1-persistent, and x4-persistent. > - (4) Host bridges each with (2) root ports > - (8) CXL memory expanders, one for each root port > - Each memory expander device supports the GET_SUPPORTED_LOGS, GET_LOG, > IDENTIFY, GET_LSA, and SET_LSA commands. > > Going forward the expectation is that where possible new UAPI visible > subsystem functionality comes with cxl_test emulation of the same. > > The build process for cxl_test is: > > make M=tools/testing/cxl > make M=tools/testing/cxl modules_install > > The implementation methodology of the test module is the same as > nfit_test where the bulk of the emulation comes from replacing symbols > that cxl_acpi and the cxl_core import with mocked implementation of > those symbols. See the "--wrap=" lines in tools/testing/cxl/Kbuild. Some > symbols need to be replaced, but are local to the modules like > match_add_root_ports(). In those cases the local symbol is marked __weak > with a strong implementation coming from tools/testing/cxl/. The goal > being to be minimally invasive to production code paths.
I went through everything except the very last patch, which I'll try to get to tomorrow when my brain is working a bit better. It looks fine to me overall. I'd like if we could remove code duplication in the mock driver, but perhaps that's the nature of the beast here. > > --- > > Dan Williams (23): > libnvdimm/labels: Introduce getters for namespace label fields > libnvdimm/labels: Add isetcookie validation helper > libnvdimm/labels: Introduce label setter helpers > libnvdimm/labels: Add a checksum calculation helper > libnvdimm/labels: Add blk isetcookie set / validation helpers > libnvdimm/labels: Add blk special cases for nlabel and position helpers > libnvdimm/labels: Add type-guid helpers > libnvdimm/labels: Add claim class helpers > libnvdimm/labels: Add address-abstraction uuid definitions > libnvdimm/labels: Add uuid helpers > libnvdimm/labels: Introduce CXL labels > cxl/pci: Make 'struct cxl_mem' device type generic > cxl/mbox: Introduce the mbox_send operation > cxl/mbox: Move mailbox and other non-PCI specific infrastructure to the > core > cxl/pci: Use module_pci_driver > cxl/mbox: Convert 'enabled_cmds' to DECLARE_BITMAP > cxl/mbox: Add exclusive kernel command support > cxl/pmem: Translate NVDIMM label commands to CXL label commands > cxl/pmem: Add support for multiple nvdimm-bridge objects > tools/testing/cxl: Introduce a mocked-up CXL port hierarchy > cxl/bus: Populate the target list at decoder create > cxl/mbox: Move command definitions to common location > tools/testing/cxl: Introduce a mock memory device + driver > > > Documentation/driver-api/cxl/memory-devices.rst | 3 > drivers/cxl/acpi.c | 65 + > drivers/cxl/core/Makefile | 1 > drivers/cxl/core/bus.c | 69 +- > drivers/cxl/core/core.h | 8 > drivers/cxl/core/mbox.c | 796 +++++++++++++++++ > drivers/cxl/core/memdev.c | 84 ++ > drivers/cxl/core/pmem.c | 32 + > drivers/cxl/cxl.h | 35 - > drivers/cxl/cxlmem.h | 186 ++++ > drivers/cxl/pci.c | 1053 > +---------------------- > drivers/cxl/pmem.c | 162 +++- > drivers/nvdimm/btt.c | 11 > drivers/nvdimm/btt.h | 4 > drivers/nvdimm/btt_devs.c | 12 > drivers/nvdimm/core.c | 40 - > drivers/nvdimm/label.c | 354 +++++--- > drivers/nvdimm/label.h | 96 +- > drivers/nvdimm/namespace_devs.c | 194 ++-- > drivers/nvdimm/nd-core.h | 5 > drivers/nvdimm/nd.h | 263 ++++++ > drivers/nvdimm/pfn_devs.c | 2 > include/linux/nd.h | 4 > tools/testing/cxl/Kbuild | 29 + > tools/testing/cxl/mock_acpi.c | 105 ++ > tools/testing/cxl/mock_pmem.c | 24 + > tools/testing/cxl/test/Kbuild | 10 > tools/testing/cxl/test/cxl.c | 587 +++++++++++++ > tools/testing/cxl/test/mem.c | 255 ++++++ > tools/testing/cxl/test/mock.c | 155 +++ > tools/testing/cxl/test/mock.h | 27 + > 31 files changed, 3234 insertions(+), 1437 deletions(-) > create mode 100644 drivers/cxl/core/mbox.c > create mode 100644 tools/testing/cxl/Kbuild > create mode 100644 tools/testing/cxl/mock_acpi.c > create mode 100644 tools/testing/cxl/mock_pmem.c > create mode 100644 tools/testing/cxl/test/Kbuild > create mode 100644 tools/testing/cxl/test/cxl.c > create mode 100644 tools/testing/cxl/test/mem.c > create mode 100644 tools/testing/cxl/test/mock.c > create mode 100644 tools/testing/cxl/test/mock.h > > base-commit: 427832674f6e2413c21ca2271ec945a720608ff2 > > (cxl.git#pending as of August 9th, 2021)
