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Date:   Wed, 21 Sep 2022 13:50:56 -0700
From:   David Matlack <dmatlack@google.com>
To:     Vishal Annapurve <vannapurve@google.com>
Cc:     x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, pbonzini@redhat.com,
        shuah@kernel.org, bgardon@google.com, seanjc@google.com,
        oupton@google.com, peterx@redhat.com, vkuznets@redhat.com
Subject: Re: [V2 PATCH 2/8] KVM: selftests: Add arch specific initialization
Message-ID: <Yyt5MHc1bwPfvBq/@google.com>
References: <20220915000448.1674802-1-vannapurve@google.com>
 <20220915000448.1674802-3-vannapurve@google.com>
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On Thu, Sep 15, 2022 at 12:04:42AM +0000, Vishal Annapurve wrote:
> Introduce arch specific API: kvm_selftest_arch_init to allow each arch to
> handle initialization before running any selftest logic.
> 
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Vishal Annapurve <vannapurve@google.com>
> ---
>  .../selftests/kvm/include/kvm_util_base.h      |  5 +++++
>  .../selftests/kvm/lib/aarch64/processor.c      | 18 +++++++++---------
>  tools/testing/selftests/kvm/lib/kvm_util.c     |  2 ++
>  .../selftests/kvm/lib/riscv/processor.c        |  4 ++++
>  .../selftests/kvm/lib/s390x/processor.c        |  4 ++++
>  .../selftests/kvm/lib/x86_64/processor.c       |  4 ++++
>  6 files changed, 28 insertions(+), 9 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index 24fde97f6121..98edbbda9f97 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -834,4 +834,9 @@ static inline int __vm_disable_nx_huge_pages(struct kvm_vm *vm)
>  	return __vm_enable_cap(vm, KVM_CAP_VM_DISABLE_NX_HUGE_PAGES, 0);
>  }
>  
> +/*
> + * API to execute architecture specific setup before executing selftest logic.

nit: s/before executing selftest logic/before main()/

("selftest logic" is vague)

> + */
> +void kvm_selftest_arch_init(void);
> +
>  #endif /* SELFTEST_KVM_UTIL_BASE_H */
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/processor.c b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> index 6f5551368944..2281d6c5d02f 100644
> --- a/tools/testing/selftests/kvm/lib/aarch64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/aarch64/processor.c
> @@ -495,15 +495,6 @@ void aarch64_get_supported_page_sizes(uint32_t ipa,
>  	close(kvm_fd);
>  }
>  
> -/*
> - * arm64 doesn't have a true default mode, so start by computing the
> - * available IPA space and page sizes early.
> - */
> -void __attribute__((constructor)) init_guest_modes(void)
> -{
> -       guest_modes_append_default();
> -}
> -
>  void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
>  	       uint64_t arg2, uint64_t arg3, uint64_t arg4, uint64_t arg5,
>  	       uint64_t arg6, struct arm_smccc_res *res)
> @@ -528,3 +519,12 @@ void smccc_hvc(uint32_t function_id, uint64_t arg0, uint64_t arg1,
>  		       [arg4] "r"(arg4), [arg5] "r"(arg5), [arg6] "r"(arg6)
>  		     : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7");
>  }
> +
> +/*
> + * arm64 doesn't have a true default mode, so start by computing the
> + * available IPA space and page sizes early.
> + */
> +void kvm_selftest_arch_init(void)
> +{
> +	guest_modes_append_default();
> +}
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 3c83838999f5..dafe4471a6c7 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -1984,4 +1984,6 @@ void __attribute((constructor)) kvm_selftest_init(void)
>  {
>  	/* Tell stdout not to buffer its content. */
>  	setbuf(stdout, NULL);
> +
> +	kvm_selftest_arch_init();
>  }

Suggest defining a default no-op implementation of
kvm_selftest_arch_init() using __weak since most architectures do not
actually need an implementation.

> diff --git a/tools/testing/selftests/kvm/lib/riscv/processor.c b/tools/testing/selftests/kvm/lib/riscv/processor.c
> index 604478151212..26660dd2ba78 100644
> --- a/tools/testing/selftests/kvm/lib/riscv/processor.c
> +++ b/tools/testing/selftests/kvm/lib/riscv/processor.c
> @@ -362,3 +362,7 @@ void vcpu_args_set(struct kvm_vcpu *vcpu, unsigned int num, ...)
>  void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
>  {
>  }
> +
> +void kvm_selftest_arch_init(void)
> +{
> +}
> diff --git a/tools/testing/selftests/kvm/lib/s390x/processor.c b/tools/testing/selftests/kvm/lib/s390x/processor.c
> index 89d7340d9cbd..8654ec74009a 100644
> --- a/tools/testing/selftests/kvm/lib/s390x/processor.c
> +++ b/tools/testing/selftests/kvm/lib/s390x/processor.c
> @@ -218,3 +218,7 @@ void vcpu_arch_dump(FILE *stream, struct kvm_vcpu *vcpu, uint8_t indent)
>  void assert_on_unhandled_exception(struct kvm_vcpu *vcpu)
>  {
>  }
> +
> +void kvm_selftest_arch_init(void)
> +{
> +}
> diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> index 2e6e61bbe81b..20bf125f9363 100644
> --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
> +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
> @@ -1311,3 +1311,7 @@ bool vm_is_unrestricted_guest(struct kvm_vm *vm)
>  
>  	return val == 'Y';
>  }
> +
> +void kvm_selftest_arch_init(void)
> +{
> +}
> -- 
> 2.37.2.789.g6183377224-goog
>