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;
Date:   Wed, 15 Jun 2022 04:28:39 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Juergen Gross <jgross@suse.com>
Cc:     Christoph Hellwig <hch@infradead.org>,
        xen-devel@lists.xenproject.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Subject: Re: [PATCH] xen: don't require virtio with grants for non-PV guests
Message-ID: <YqnCZ+EKZeZ5AEnr@infradead.org>
References: <20220615084835.27113-1-jgross@suse.com>
 <YqnBZhiLOHnoalbC@infradead.org>
 <9b9785f5-085b-0882-177f-d8418c366beb@suse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <9b9785f5-085b-0882-177f-d8418c366beb@suse.com>
Precedence: bulk

On Wed, Jun 15, 2022 at 01:26:27PM +0200, Juergen Gross wrote:
> On 15.06.22 13:24, Christoph Hellwig wrote:
> > I don't think this command line mess is a good idea.  Instead the
> > brand new grant devices need to be properly advertised in the device
> > tree, and any device that isn't a grant device doesn't need
> > VIRTIO_F_ACCESS_PLATFORM.  No need for a command line or user
> > intervention.
> 
> And on x86?

ACPI tables or whatever mechanism you otherwise use to advertise grant
based DMA.  But that is irrelevant for now, as the code in mainline
only supports DT on arm/arm64 anyay.