Re: [PATCH v4 09/18] KVM: arm64: selftests: Add guest support to get the vcpuid

From: Reiji Watanabe
Date: Sun Sep 12 2021 - 03:05:50 EST

Hi Raghu and all,

On Wed, Sep 8, 2021 at 6:38 PM Raghavendra Rao Ananta
<rananta@xxxxxxxxxx> wrote:
> At times, such as when in the interrupt handler, the guest wants
> to get the vcpuid that it's running on. As a result, introduce
> get_vcpuid() that returns the vcpuid of the calling vcpu. At its
> backend, the VMM prepares a map of vcpuid and mpidr during VM
> initialization and exports the map to the guest for it to read.

How about using TPIDR_EL1 to hold the vcpuid ?
i.e. have aarch64_vcpu_setup() set the register to vcpuid and
guest_get_vcpuid() simply return a value of the register.
This would be a simpler solution to implement.