linux-kernel - Re: [PATCH v5 09/14] KVM: arm64: selftests: Add guest support to get the vcpuid

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Date:   Mon, 13 Sep 2021 14:21:49 -0700
From:   Ricardo Koller <ricarkol@...gle.com>
To:     Raghavendra Rao Ananta <rananta@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Marc Zyngier <maz@...nel.org>,
        Andrew Jones <drjones@...hat.com>,
        James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Peter Shier <pshier@...gle.com>,
        Oliver Upton <oupton@...gle.com>,
        Reiji Watanabe <reijiw@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH v5 09/14] KVM: arm64: selftests: Add guest support to get
 the vcpuid

On Mon, Sep 13, 2021 at 08:49:25PM +0000, Raghavendra Rao Ananta wrote:
> At times, such as when in the interrupt handler, the guest wants
> to get the vcpuid that it's running on to pull the per-cpu private
> data. As a result, introduce guest_get_vcpuid() that returns the
> vcpuid of the calling vcpu. The interface is architecture
> independent, but defined only for arm64 as of now.
> 
> Suggested-by: Reiji Watanabe <reijiw@...gle.com>
> Signed-off-by: Raghavendra Rao Ananta <rananta@...gle.com>
> ---
>  tools/testing/selftests/kvm/include/kvm_util.h      | 2 ++
>  tools/testing/selftests/kvm/lib/aarch64/processor.c | 6 ++++++
>  2 files changed, 8 insertions(+)
> 
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index 010b59b13917..5770751a5735 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -400,4 +400,6 @@ uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc);
>  int vm_get_stats_fd(struct kvm_vm *vm);
>  int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
>  
> +int guest_get_vcpuid(void);
> +
>  #endif /* SELFTEST_KVM_UTIL_H */
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> index db64ee206064..f1255f44dad0 100644
> --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> @@ -277,6 +277,7 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, int vcpuid, struct kvm_vcpu_init *ini
>  	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TCR_EL1), tcr_el1);
>  	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_MAIR_EL1), DEFAULT_MAIR_EL1);
>  	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TTBR0_EL1), vm->pgd);
> +	set_reg(vm, vcpuid, KVM_ARM64_SYS_REG(SYS_TPIDR_EL1), vcpuid);
>  }
>  
>  void vcpu_dump(FILE *stream, struct kvm_vm *vm, uint32_t vcpuid, uint8_t indent)
> @@ -426,3 +427,8 @@ void vm_install_exception_handler(struct kvm_vm *vm, int vector,
>  	assert(vector < VECTOR_NUM);
>  	handlers->exception_handlers[vector][0] = handler;
>  }
> +
> +int guest_get_vcpuid(void)
> +{
> +	return read_sysreg(tpidr_el1);
> +}
> -- 
> 2.33.0.309.g3052b89438-goog
>

Very nice!

Reviewed-by: Ricardo Koller <ricarkol@...gle.com>