Re: [PATCH v19 6/7] KVM: arm64: Add support for the KVM PTP service

Zenghui Yu
2021-04-17T08:59:56Z

On 2021/3/30 22:54, Marc Zyngier wrote:
> +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_HYP_KVM_PTP_FUNC_ID: 0x86000001

Per include/linux/arm-smccc.h, this should be
ARM_SMCCC_VENDOR_HYP_KVM_PTP_FUNC_ID.

> +
> +This hypercall uses the SMC32/HVC32 calling convention:
> +
> +ARM_SMCCC_HYP_KVM_PTP_FUNC_ID

ditto

> + ============= ========== ==========
> + Function ID: (uint32) 0x86000001
> + Arguments: (uint32) KVM_PTP_VIRT_COUNTER(0)
> + KVM_PTP_PHYS_COUNTER(1)