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Message-ID: <61759137-0182-8eed-6413-80a8fc82c6e8@redhat.com>
Date:   Wed, 6 Oct 2021 15:36:15 +0200
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Subject: Re: [PATCH MANUALSEL 5.14 1/9] selftests: KVM: Align SMCCC call with
 the spec in steal_time
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To:     Sasha Levin <sashal@kernel.org>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Cc:     Oliver Upton <oupton@google.com>,
        Andrew Jones <drjones@redhat.com>, shuah@kernel.org,
        kvm@vger.kernel.org, linux-kselftest@vger.kernel.org
References: <20211006133021.271905-1-sashal@kernel.org>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <20211006133021.271905-1-sashal@kernel.org>
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On 06/10/21 15:30, Sasha Levin wrote:
> From: Oliver Upton <oupton@google.com>
> 
> [ Upstream commit 01f91acb55be7aac3950b89c458bcea9ef6e4f49 ]
> 
> The SMC64 calling convention passes a function identifier in w0 and its
> parameters in x1-x17. Given this, there are two deviations in the
> SMC64 call performed by the steal_time test: the function identifier is
> assigned to a 64 bit register and the parameter is only 32 bits wide.
> 
> Align the call with the SMCCC by using a 32 bit register to handle the
> function identifier and increasing the parameter width to 64 bits.
> 
> Suggested-by: Andrew Jones <drjones@redhat.com>
> Signed-off-by: Oliver Upton <oupton@google.com>
> Reviewed-by: Andrew Jones <drjones@redhat.com>
> Message-Id: <20210921171121.2148982-3-oupton@google.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>   tools/testing/selftests/kvm/steal_time.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
> index ecec30865a74..aafaa8e38b7c 100644
> --- a/tools/testing/selftests/kvm/steal_time.c
> +++ b/tools/testing/selftests/kvm/steal_time.c
> @@ -118,12 +118,12 @@ struct st_time {
>   	uint64_t st_time;
>   };
>   
> -static int64_t smccc(uint32_t func, uint32_t arg)
> +static int64_t smccc(uint32_t func, uint64_t arg)
>   {
>   	unsigned long ret;
>   
>   	asm volatile(
> -		"mov	x0, %1\n"
> +		"mov	w0, %w1\n"
>   		"mov	x1, %2\n"
>   		"hvc	#0\n"
>   		"mov	%0, x0\n"
> 

Acked-by: Paolo Bonzini <pbonzini@redhat.com>