Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Message-ID: <1069466fa3a373e92d9db18957674b1d9c6e9cf2.camel@gmail.com>
Subject: Re: [PATCH v2 6/6] powerpc/pseries/iommu: Avoid errors when DDW
 starts at 0x00
From:   Leonardo Bras <leobras.c@gmail.com>
To:     Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Thiago Jung Bauermann <bauerman@linux.ibm.com>,
        Ram Pai <linuxram@us.ibm.com>
Cc:     linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Date:   Fri, 26 Jun 2020 14:46:46 -0300
In-Reply-To: <20200624062411.367796-7-leobras.c@gmail.com>
References: <20200624062411.367796-1-leobras.c@gmail.com>
         <20200624062411.367796-7-leobras.c@gmail.com>
Organization: IBM
Content-Type: text/plain; charset="UTF-8"
User-Agent: Evolution 3.34.4 (3.34.4-1.fc31) 
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, 2020-06-24 at 03:24 -0300, Leonardo Bras wrote:
> As of today, enable_ddw() will return a non-null DMA address if the
> created DDW maps the whole partition. If the address is valid,
> iommu_bypass_supported_pSeriesLP() will consider iommu bypass enabled.
> 
> This can cause some trouble if the DDW happens to start at 0x00.
> 
> Instead if checking if the address is non-null, check directly if
> the DDW maps the whole partition, so it can bypass iommu.
> 
> Signed-off-by: Leonardo Bras <leobras.c@gmail.com>

This patch has a bug in it. I will rework it soon.
Please keep reviewing patches 1-5.

Best regards,
Leonardo