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Date: Fri, 4 Sep 2020 12:39:39 +0200
From: Heiko Carstens <hca@linux.ibm.com>
Subject: Re: [PATCH 1/2] s390x: uv: Add destroy page call
Message-ID: <20200904103939.GE6075@osiris>
References: <20200903131435.2535-1-frankja@linux.ibm.com>
 <20200903131435.2535-2-frankja@linux.ibm.com>
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To: Janosch Frank <frankja@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, borntraeger@de.ibm.com, gor@linux.ibm.com, imbrenda@linux.ibm.com, kvm@vger.kernel.org, david@redhat.com

On Thu, Sep 03, 2020 at 09:14:34AM -0400, Janosch Frank wrote:
> +int uv_destroy_page(unsigned long paddr)
> +{
> +	struct uv_cb_cfs uvcb = {
> +		.header.cmd = UVC_CMD_DESTR_SEC_STOR,
> +		.header.len = sizeof(uvcb),
> +		.paddr = paddr
> +	};
> +
> +	if (uv_call(0, (u64)&uvcb))
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +
>  /*
>   * Requests the Ultravisor to encrypt a guest page and make it
>   * accessible to the host for paging (export).
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 373542ca1113..cfb0017f33a7 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -2679,7 +2679,7 @@ static int __s390_reset_acc(pte_t *ptep, unsigned long addr,
>  	pte_t pte = READ_ONCE(*ptep);
>  
>  	if (pte_present(pte))
> -		WARN_ON_ONCE(uv_convert_from_secure(pte_val(pte) & PAGE_MASK));
> +		WARN_ON_ONCE(uv_destroy_page(pte_val(pte) & PAGE_MASK));

Why not put the WARN_ON_ONCE() into uv_destroy_page() and make that
function return void?