From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH v4 5/7] xen/arm: introduce
	GNTTABOP_cache_flush
Date: Fri, 10 Oct 2014 13:04:42 +0100
Message-ID: <5437CB5A.3090608@linaro.org>
References: <alpine.DEB.2.02.1410101237420.17038@kaball.uk.xensource.com>
	<1412941440-5646-5-git-send-email-stefano.stabellini@eu.citrix.com>
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To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, xen-devel@lists.xensource.com
Cc: julien.grall@citrix.com, Ian.Campbell@citrix.com
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Hi Stefano,

On 10/10/2014 12:43, Stefano Stabellini wrote:
> +static int __gnttab_cache_flush(gnttab_cache_flush_t *cflush)
> +{
> +    struct domain *d, *owner;
> +    struct page_info *page;
> +    uint64_t mfn;
> +    void *v;
> +
> +    if ( (cflush->offset >= PAGE_SIZE) ||
> +         (cflush->length > PAGE_SIZE) ||
> +         (cflush->offset + cflush->length > PAGE_SIZE) )
> +        return -EINVAL;
> +
> +    if ( cflush->length == 0 || cflush->op == 0 )
> +        return 0;
> +
> +    /* currently unimplemented */
> +    if ( cflush->op & GNTTAB_CACHE_SOURCE_GREF )
> +        return -EOPNOTSUPP;

I may have miss a part of the discussion. What is the purpose of 
introducing a flag that is not supported? Do we expect to implement on 
Xen 4.6?

-- 
Julien Grall