mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-27 12:57:53 +00:00
5a08146d9b
The PTP hypercall documentation doesn't produce the best-looking table when formatting in HTML as all of the return value definitions end up on the same line. Reformat the PTP hypercall documentation to follow the formatting used by hypercalls.rst. Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Fuad Tabba <tabba@google.com> Acked-by: Oliver Upton <oliver.upton@linux.dev> Link: https://lore.kernel.org/r/20240423150538.2103045-26-tabba@google.com Signed-off-by: Marc Zyngier <maz@kernel.org>
35 lines
2 KiB
ReStructuredText
35 lines
2 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
PTP_KVM support for arm/arm64
|
|
=============================
|
|
|
|
PTP_KVM is used for high precision time sync between host and guests.
|
|
It relies on transferring the wall clock and counter value from the
|
|
host to the guest using a KVM-specific hypercall.
|
|
|
|
``ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID``
|
|
----------------------------------------
|
|
|
|
Retrieve current time information for the specific counter. There are no
|
|
endianness restrictions.
|
|
|
|
+---------------------+-------------------------------------------------------+
|
|
| Presence: | Optional |
|
|
+---------------------+-------------------------------------------------------+
|
|
| Calling convention: | HVC32 |
|
|
+---------------------+----------+--------------------------------------------+
|
|
| Function ID: | (uint32) | 0x86000001 |
|
|
+---------------------+----------+----+---------------------------------------+
|
|
| Arguments: | (uint32) | R1 | ``KVM_PTP_VIRT_COUNTER (0)`` |
|
|
| | | +---------------------------------------+
|
|
| | | | ``KVM_PTP_PHYS_COUNTER (1)`` |
|
|
+---------------------+----------+----+---------------------------------------+
|
|
| Return Values: | (int32) | R0 | ``NOT_SUPPORTED (-1)`` on error, else |
|
|
| | | | upper 32 bits of wall clock time |
|
|
| +----------+----+---------------------------------------+
|
|
| | (uint32) | R1 | Lower 32 bits of wall clock time |
|
|
| +----------+----+---------------------------------------+
|
|
| | (uint32) | R2 | Upper 32 bits of counter |
|
|
| +----------+----+---------------------------------------+
|
|
| | (uint32) | R3 | Lower 32 bits of counter |
|
|
+---------------------+----------+----+---------------------------------------+
|