Re: [PATCH v6 0/3] PCI/ACPI: add support for CXL _OSC

["Rafael J. Wysocki" <rafael.j.wysocki@intel.com>]

On 4/23/2022 12:24 AM, Verma, Vishal L wrote:
> On Wed, 2022-04-13 at 01:36 -0600, Vishal Verma wrote:
>> Changes since v5[1]:
>> - Collect an reviewed-by tags from Rafael, Adam, and David
>> - Fix a couple of missed s/CXL/extended/ in acpi_bus.h (Rafael)
> Rafael, or Bjorn,
>
> Dan has offered to take this through cxl.git. Any objections to that -
> would you prefer it to go through either the PCI or ACPI trees instead?

This would be fine with me, but I can take the series too.


>> Add support for using the CXL definition of _OSC where applicable, and
>> negotiating CXL specific support and control bits.
>>
>> Patch 1 is a preliminary cleanup that replaces open-coded pointer
>> arithmetic to retrieve the Control DWORD with an inline helper.
>>
>> Patch 2 adds the new CXL _OSC UUID, and uses it instead of the PCI UUID
>> when a root port is CXL enabled. It provides a fallback method for
>> CXL-1.1 platforms that may not implement the CXL-2.0 _OSC.
>>
>> Patch 3 performs negotiation for the CXL specific _OSC support and
>> control bits.
>>
>> I've tested these against a custom qemu[2], which adds the CXL _OSC (in
>> addition to other CXL support). Specifically, _OSC support is added
>> here[3].
>>
>> [1]: https://lore.kernel.org/linux-cxl/20220406023746.2807328-1-vishal.l.verma@intel.com
>> [2]: https://gitlab.com/jic23/qemu/-/tree/cxl-v8-draft
>> [3]: https://gitlab.com/jic23/qemu/-/commit/1d67df6b6e3716c27462873f3451956f5c0673a3
>>
>> Dan Williams (1):
>>    PCI/ACPI: Prefer CXL _OSC instead of PCIe _OSC for CXL host bridges
>>
>> Vishal Verma (2):
>>    PCI/ACPI: add a helper for retrieving _OSC Control DWORDs
>>    PCI/ACPI: negotiate CXL _OSC
>>
>>   include/linux/acpi.h    |  42 ++++++-
>>   include/acpi/acpi_bus.h |  12 +-
>>   drivers/acpi/bus.c      |   2 +-
>>   drivers/acpi/pci_root.c | 240 +++++++++++++++++++++++++++++++++++-----
>>   4 files changed, 262 insertions(+), 34 deletions(-)
>>
>>
>> base-commit: 05e815539f3f161585c13a9ab023341bade2c52f