Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Wed, 24 Jul 2019 12:53:10 +0300
From:   Ilias Apalodimas <ilias.apalodimas@linaro.org>
To:     Jose Abreu <Jose.Abreu@synopsys.com>
Cc:     David Miller <davem@davemloft.net>,
        "jonathanh@nvidia.com" <jonathanh@nvidia.com>,
        "robin.murphy@arm.com" <robin.murphy@arm.com>,
        "lists@bofh.nu" <lists@bofh.nu>,
        "Joao.Pinto@synopsys.com" <Joao.Pinto@synopsys.com>,
        "alexandre.torgue@st.com" <alexandre.torgue@st.com>,
        "maxime.ripard@bootlin.com" <maxime.ripard@bootlin.com>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-stm32@st-md-mailman.stormreply.com" 
        <linux-stm32@st-md-mailman.stormreply.com>,
        "wens@csie.org" <wens@csie.org>,
        "mcoquelin.stm32@gmail.com" <mcoquelin.stm32@gmail.com>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        "peppe.cavallaro@st.com" <peppe.cavallaro@st.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH net-next 3/3] net: stmmac: Introducing support for Page
 Pool
Message-ID: <20190724095310.GA12991@apalos>
References: <BYAPR12MB32692AF2BA127C5DA5B74804D3C70@BYAPR12MB3269.namprd12.prod.outlook.com>
 <6c769226-bdd9-6fe0-b96b-5a0d800fed24@arm.com>
 <8756d681-e167-fe4a-c6f0-47ae2dcbb100@nvidia.com>
 <20190723.115112.1824255524103179323.davem@davemloft.net>
 <20190724085427.GA10736@apalos>
 <BYAPR12MB3269AA9955844E317B62A239D3C60@BYAPR12MB3269.namprd12.prod.outlook.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <BYAPR12MB3269AA9955844E317B62A239D3C60@BYAPR12MB3269.namprd12.prod.outlook.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Jose, 
> From: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> Date: Jul/24/2019, 09:54:27 (UTC+00:00)
> 
> > Hi David, 
> > 
> > > From: Jon Hunter <jonathanh@nvidia.com>
> > > Date: Tue, 23 Jul 2019 13:09:00 +0100
> > > 
> > > > Setting "iommu.passthrough=1" works for me. However, I am not sure where
> > > > to go from here, so any ideas you have would be great.
> > > 
> > > Then definitely we are accessing outside of a valid IOMMU mapping due
> > > to the page pool support changes.
> > 
> > Yes. On the netsec driver i did test with and without SMMU to make sure i am not
> > breaking anything.
> > Since we map the whole page on the API i think some offset on the driver causes
> > that. In any case i'll have another look on page_pool to make sure we are not
> > missing anything. 
> 
> Ilias, can it be due to this:
> 
> stmmac_main.c:
> 	pp_params.order = DIV_ROUND_UP(priv->dma_buf_sz, PAGE_SIZE);
> 
> page_pool.c:
> 	dma = dma_map_page_attrs(pool->p.dev, page, 0,
> 				 (PAGE_SIZE << pool->p.order),
> 				 pool->p.dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
> 
> "order", will be at least 1 and then mapping the page can cause overlap 
> ?

well the API is calling the map with the correct page, page offset (0) and size
right? I don't see any overlapping here. Aren't we mapping what we allocate?

Why do you need higher order pages? Jumbo frames? Can we do a quick test with
the order being 0?

Thanks,
/Ilias