[PATCH v9 8/8] ABI: sysfs-bus-pci: add documentation for p2pmem allocate

Logan Gunthorpe
2022-08-25T15:25:32Z

Add documentation for the p2pmem/allocate binary file which allows
for allocating p2pmem buffers in userspace for passing to drivers
that support them. (Currently only O_DIRECT to NVMe devices.)

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
Documentation/ABI/testing/sysfs-bus-pci | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 6fc2c2efe8ab..dca5e032b4fa 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -171,7 +171,7 @@ Description:
binary file containing the Vital Product Data for the
device. It should follow the VPD format defined in
PCI Specification 2.1 or 2.2, but users should consider
- that some devices may have incorrectly formatted data.
+ that some devices may have incorrectly formatted data.
If the underlying VPD has a writable section then the
corresponding section of this file will be writable.

@@ -407,6 +407,16 @@ Description:
file contains a '1' if the memory has been published for
use outside the driver that owns the device.

+What: /sys/bus/pci/devices/.../p2pmem/allocate
+Date: August 2022
+Contact: Logan Gunthorpe <logang@deltatee.com>
+Description:
+ Thes attribute allows mapping p2pmem into userspace. For
+ each mmap() call on this file, the kernel will allocate
+ a chunk of Peer-to-Peer memory for use in Peer-to-Peer
+ transactions. This memory can be used in O_DIRECT calls
+ to NVMe backed files for Peer-to-Peer copies.
+
What: /sys/bus/pci/devices/.../link/clkpm
/sys/bus/pci/devices/.../link/l0s_aspm
/sys/bus/pci/devices/.../link/l1_aspm
--
2.30.2