Message-ID: <59a61553a81282fed88c03af096b2a0830b94302.camel@linux.ibm.com>
Subject: Re: [PATCH v6 4/6] s390/pci: Use dma-iommu layer
From:   Niklas Schnelle <schnelle@linux.ibm.com>
To:     Matthew Rosato <mjrosato@linux.ibm.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Wenjia Zhang <wenjia@linux.ibm.com>
Cc:     Gerd Bayer <gbayer@linux.ibm.com>,
        Pierre Morel <pmorel@linux.ibm.com>, iommu@lists.linux.dev,
        linux-s390@vger.kernel.org, borntraeger@linux.ibm.com,
        hca@linux.ibm.com, gor@linux.ibm.com,
        gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
        svens@linux.ibm.com, linux-kernel@vger.kernel.org,
        Julian Ruess <julianr@linux.ibm.com>
Date:   Fri, 17 Feb 2023 09:51:50 +0100
In-Reply-To: <4ad0d2b9-2465-b42d-c0f9-b48caadfd72c@linux.ibm.com>
References: <20230215120327.947336-1-schnelle@linux.ibm.com>
         <20230215120327.947336-5-schnelle@linux.ibm.com>
         <4ad0d2b9-2465-b42d-c0f9-b48caadfd72c@linux.ibm.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
User-Agent: Evolution 3.46.3 (3.46.3-1.fc37) 
MIME-Version: 1.0
Precedence: bulk

On Wed, 2023-02-15 at 13:00 -0500, Matthew Rosato wrote:
> On 2/15/23 7:03 AM, Niklas Schnelle wrote:
> > While s390 already has a standard IOMMU driver and previous changes hav=
e
> > added I/O TLB flushing operations this driver is currently only used fo=
r
> > user-space PCI access such as vfio-pci. For the DMA API s390 instead
> > utilizes its own implementation in arch/s390/pci/pci_dma.c which drives
> > the same hardware and shares some code but requires a complex and
> > fragile hand over between DMA API and IOMMU API use of a device and
> > despite code sharing still leads to significant duplication and
> > maintenance effort. Let's utilize the common code DMAP API
> > implementation from drivers/iommu/dma-iommu.c instead allowing us to
> > get rid of arch/s390/pci/pci_dma.c.
> >=20
> > Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
> > ---
>=20
> FYI, this patch doesn't fit on top of iommu-next, I'd guess at least due =
to baolu's 'Retire detach_dev callback' series, which removed .detach_dev a=
nd added .set_platform_dma_ops for s390-iommu.  That's relevant here, becau=
se now that this patch enables dma-iommu for s390 and removes the platform =
DMA ops it must now remove .set_platform_dma_ops/s390_iommu_set_platform_dm=
a for s390-iommu.
>=20
> Matt


Ok, yes this series is currently against v6.2-rc8. Should I rebase
against iommu-next and send a v7 before further review or after?

Thanks,
Niklas