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OpenCloudOS-Kernel/Documentation/virt/kvm/arm/ptp_kvm.rst

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KVM: arm64: Add support for the KVM PTP service Implement the hypervisor side of the KVM PTP interface. The service offers wall time and cycle count from host to guest. The caller must specify whether they want the host's view of either the virtual or physical counter. Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com
2020-12-09 14:09:29 +08:00
.. 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.
KVM: arm64: Fix Function ID typo for PTP_KVM service Per include/linux/arm-smccc.h, the Function ID of PTP_KVM service is defined as ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID. Fix the typo in documentation to keep the git grep consistent. Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210417113804.1992-1-yuzenghui@huawei.com
2021-04-17 19:38:04 +08:00
* ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID: 0x86000001
KVM: arm64: Add support for the KVM PTP service Implement the hypervisor side of the KVM PTP interface. The service offers wall time and cycle count from host to guest. The caller must specify whether they want the host's view of either the virtual or physical counter. Signed-off-by: Jianyong Wu <jianyong.wu@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20201209060932.212364-7-jianyong.wu@arm.com
2020-12-09 14:09:29 +08:00
This hypercall uses the SMC32/HVC32 calling convention:
KVM: arm64: Fix Function ID typo for PTP_KVM service Per include/linux/arm-smccc.h, the Function ID of PTP_KVM service is defined as ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID. Fix the typo in documentation to keep the git grep consistent. Signed-off-by: Zenghui Yu <yuzenghui@huawei.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210417113804.1992-1-yuzenghui@huawei.com
2021-04-17 19:38:04 +08:00
ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID
KVM: arm64: Fix table format for PTP documentation The documentation build legitimately screams about the PTP documentation table being misformated. Fix it by adjusting the table width guides. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Marc Zyngier <maz@kernel.org>
2021-04-08 21:31:24 +08:00
============== ======== =====================================
Function ID: (uint32) 0x86000001
Arguments: (uint32) KVM_PTP_VIRT_COUNTER(0)
KVM_PTP_PHYS_COUNTER(1)
Return Values: (int32) NOT_SUPPORTED(-1) on error, or
(uint32) Upper 32 bits of wall clock time (r0)
(uint32) Lower 32 bits of wall clock time (r1)
(uint32) Upper 32 bits of counter (r2)
(uint32) Lower 32 bits of counter (r3)
Endianness: No Restrictions.
============== ======== =====================================