9795ec6a60
Change a few uses of ARM_SMCCC_VENDOR_HYP_KVM_FOO_FUNC_ID to ARM_SMCCC_KVM_FUNC_FOO. Signed-off-by: Keir Fraser <keirf@google.com> Bug: 265943840 Change-Id: Id1642243ca4105a23e808cf28d13bfb81d9a5ac2
36 lines
2.0 KiB
ReStructuredText
36 lines
2.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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PTP_KVM support for arm/arm64
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=============================
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PTP_KVM is used for high precision time sync between host and guests.
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It relies on transferring the wall clock and counter value from the
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host to the guest using a KVM-specific hypercall.
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``ARM_SMCCC_KVM_FUNC_PTP``
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----------------------------------------
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Retrieve current time information for the specific counter. There are no
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endianness restrictions.
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+---------------------+-------------------------------------------------------+
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| Presence: | Optional |
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+---------------------+-------------------------------------------------------+
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| Calling convention: | HVC32 |
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+---------------------+----------+--------------------------------------------+
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| Function ID: | (uint32) | 0x86000001 |
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+---------------------+----------+----+---------------------------------------+
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| Arguments: | (uint32) | R1 | ``KVM_PTP_VIRT_COUNTER (0)`` |
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| | | +---------------------------------------+
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| | | | ``KVM_PTP_PHYS_COUNTER (1)`` |
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+---------------------+----------+----+---------------------------------------+
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| Return Values: | (int32) | R0 | ``NOT_SUPPORTED (-1)`` on error, else |
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| | | | upper 32 bits of wall clock time |
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| +----------+----+---------------------------------------+
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| | (uint32) | R1 | Lower 32 bits of wall clock time |
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| +----------+----+---------------------------------------+
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| | (uint32) | R2 | Upper 32 bits of counter |
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| +----------+----+---------------------------------------+
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| | (uint32) | R3 | Lower 32 bits of counter |
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+---------------------+----------+----+---------------------------------------+
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