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