Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <b151d65b-7b67-002c-49f2-b7334c201130@zytor.com>
Date:   Mon, 7 Nov 2022 09:30:38 -0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.1
Subject: Re: [PATCH linux-next] KVM: x86: Replace IS_ERR() with IS_ERR_VALUE()
Content-Language: en-US
To:     yexingchen116@gmail.com, seanjc@google.com
Cc:     pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
        bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        ye xingchen <ye.xingchen@zte.com.cn>
References: <20221020113943.400103-1-ye.xingchen@zte.com.cn>
From:   "H. Peter Anvin" <hpa@zytor.com>
In-Reply-To: <20221020113943.400103-1-ye.xingchen@zte.com.cn>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10/20/22 04:39, yexingchen116@gmail.com wrote:
> From: ye xingchen <ye.xingchen@zte.com.cn>
> 
> Avoid type casts that are needed for IS_ERR() and use
> IS_ERR_VALUE() instead.
> 
> Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
> ---
>   arch/x86/kvm/x86.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 4bd5f8a751de..1c260f716c3b 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12414,7 +12414,7 @@ void __user * __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
>   		 */
>   		hva = vm_mmap(NULL, 0, size, PROT_READ | PROT_WRITE,
>   			      MAP_SHARED | MAP_ANONYMOUS, 0);
> -		if (IS_ERR((void *)hva))
> +		if (IS_ERR_VALUE(hva))
>   			return (void __user *)hva;
>   	} else {
>   		if (!slot || !slot->npages)

This seems to imply IS_ERR() is misdesigned.

It would be nice to have IS_ERR() contain the appropriate casts. If we 
want to enforce that the argument is a pointer, add IS_ERR_PTR()?

	-hpa