linux-kernel - Re: [PATCH 5/6] KVM: selftests: Move hypercall() to hyper.h

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Message-ID: <Y2lO1HQtaMBCGpcZ@google.com>
Date:   Mon, 7 Nov 2022 10:30:44 -0800
From:   David Matlack <dmatlack@...gle.com>
To:     Vipin Sharma <vipinsh@...gle.com>
Cc:     seanjc@...gle.com, pbonzini@...hat.com, vkuznets@...hat.com,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/6] KVM: selftests: Move hypercall() to hyper.h

On Fri, Nov 04, 2022 at 09:57:03PM -0700, Vipin Sharma wrote:
> hypercall() can be used by other hyperv tests, move it to hyperv.h.
> 
> Signed-off-by: Vipin Sharma <vipinsh@...gle.com>
> ---
>  .../selftests/kvm/include/x86_64/hyperv.h       | 17 +++++++++++++++++
>  .../selftests/kvm/x86_64/hyperv_features.c      | 17 -----------------
>  2 files changed, 17 insertions(+), 17 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/include/x86_64/hyperv.h b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> index 9d8c325af1d9..87d8d9e444f7 100644
> --- a/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> +++ b/tools/testing/selftests/kvm/include/x86_64/hyperv.h
> @@ -199,4 +199,21 @@ static inline uint64_t hv_linux_guest_id(void)
>  	       ((uint64_t)LINUX_VERSION_CODE << 16);
>  }
>  
> +static inline uint8_t hypercall(u64 control, vm_vaddr_t input_address,
> +				vm_vaddr_t output_address, uint64_t *hv_status)
> +{
> +	uint8_t vector;
> +
> +	/* Note both the hypercall and the "asm safe" clobber r9-r11. */
> +	asm volatile("mov %[output_address], %%r8\n\t"
> +		     KVM_ASM_SAFE("vmcall")
> +		     : "=a" (*hv_status),
> +		       "+c" (control), "+d" (input_address),
> +		       KVM_ASM_SAFE_OUTPUTS(vector)
> +		     : [output_address] "r"(output_address),
> +		       "a" (-EFAULT)
> +		     : "cc", "memory", "r8", KVM_ASM_SAFE_CLOBBERS);
> +	return vector;
> +}

Since this function is Hyper-V specific it probably makes sense to
rename it to hyperv_hypercall() as part of moving it to library, e.g. to
differentiate it from kvm_hypercall().

> +
>  #endif /* !SELFTEST_KVM_HYPERV_H */
> diff --git a/tools/testing/selftests/kvm/x86_64/hyperv_features.c b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> index b5a42cf1ad9d..31b22ee07dfb 100644
> --- a/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> +++ b/tools/testing/selftests/kvm/x86_64/hyperv_features.c
> @@ -13,23 +13,6 @@
>  #include "processor.h"
>  #include "hyperv.h"
>  
> -static inline uint8_t hypercall(u64 control, vm_vaddr_t input_address,
> -				vm_vaddr_t output_address, uint64_t *hv_status)
> -{
> -	uint8_t vector;
> -
> -	/* Note both the hypercall and the "asm safe" clobber r9-r11. */
> -	asm volatile("mov %[output_address], %%r8\n\t"
> -		     KVM_ASM_SAFE("vmcall")
> -		     : "=a" (*hv_status),
> -		       "+c" (control), "+d" (input_address),
> -		       KVM_ASM_SAFE_OUTPUTS(vector)
> -		     : [output_address] "r"(output_address),
> -		       "a" (-EFAULT)
> -		     : "cc", "memory", "r8", KVM_ASM_SAFE_CLOBBERS);
> -	return vector;
> -}
> -
>  struct msr_data {
>  	uint32_t idx;
>  	bool available;
> -- 
> 2.38.1.273.g43a17bfeac-goog
>