mbox series

[00/23] cxl_test: Enable CXL Topology and UAPI regression tests

Message ID 162854806653.1980150.3354618413963083778.stgit@dwillia2-desk3.amr.corp.intel.com (mailing list archive)
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Series cxl_test: Enable CXL Topology and UAPI regression tests | expand

Message

Dan Williams Aug. 9, 2021, 10:27 p.m. UTC
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.

---

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)

Comments

Ben Widawsky Aug. 10, 2021, 10:10 p.m. UTC | #1
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)
Dan Williams Aug. 10, 2021, 10:58 p.m. UTC | #2
On Tue, Aug 10, 2021 at 3:10 PM Ben Widawsky <ben.widawsky@intel.com> wrote:
>
> 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.

Well, maybe not. I.e. I don't think it would be out of the question to
wrap this common sequence into a helper that both cxl_pci and
cxl_mock_mem share:

        rc = cxl_mem_enumerate_cmds(cxlm);
        if (rc)
                return rc;

        rc = cxl_mem_identify(cxlm);
        if (rc)
                return rc;

        rc = cxl_mem_create_range_info(cxlm);
        if (rc)
                return rc;

        cxlmd = devm_cxl_add_memdev(dev, cxlm);
        if (IS_ERR(cxlmd))
                return PTR_ERR(cxlmd);

        if (range_len(&cxlm->pmem_range) && IS_ENABLED(CONFIG_CXL_PMEM))
                rc = devm_cxl_add_nvdimm(dev, cxlmd);

...or are you thinking of a different place where there's duplication?