26 lines
1.1 KiB
ReStructuredText
26 lines
1.1 KiB
ReStructuredText
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.. 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_VENDOR_HYP_KVM_PTP_FUNC_ID: 0x86000001
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This hypercall uses the SMC32/HVC32 calling convention:
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ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID
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============== ======== =====================================
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Function ID: (uint32) 0x86000001
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Arguments: (uint32) KVM_PTP_VIRT_COUNTER(0)
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KVM_PTP_PHYS_COUNTER(1)
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Return Values: (int32) NOT_SUPPORTED(-1) on error, or
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(uint32) Upper 32 bits of wall clock time (r0)
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(uint32) Lower 32 bits of wall clock time (r1)
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(uint32) Upper 32 bits of counter (r2)
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(uint32) Lower 32 bits of counter (r3)
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Endianness: No Restrictions.
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============== ======== =====================================
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