From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [RFC PATCH 0/4] Stop losing firmware-set DMA masks Date: Tue, 10 Jul 2018 20:02:32 +0200 Message-ID: <20180710180232.GA26285@lst.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Robin Murphy Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Palmer Dabbelt , sudeep.holla-5wv7dgnIgG8@public.gmane.org, linux-riscv-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org > These patches attempt to deal with this in the simplest way possible by > generalising the specific quirk for 32-bit bridges into an arbitrary > mask which can then also be plumbed into the firmware code. In the > interest of being minimally invasive, I've only included a point fix > for the IOMMU issue as seen on arm64 - there may be further tweaks > needed in DMA ops to catch all possible incarnations of this problem, > but this initial RFC is mostly about the impact beyond the dma-mapping > subsystem itself. Thanks, this looks very nice to me. In fact it probably solves the RISC-V/Xiling problem as well if we can just add the dma-ranges property to the device tree for the affected systems. Palmer, do you know how easily the DT could be updated for that case? > > Robin. > > > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-May/580804.html > [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/474443.html > > Robin Murphy (4): > dma-mapping: Generalise dma_32bit_limit flag > ACPI/IORT: Set bus DMA mask as appropriate > of/device: Set bus DMA mask as appropriate > iommu/dma: Respect bus DMA limit for IOVAs > > arch/x86/kernel/pci-dma.c | 2 +- > drivers/acpi/arm64/iort.c | 1 + > drivers/iommu/dma-iommu.c | 3 +++ > drivers/of/device.c | 1 + > include/linux/device.h | 6 +++--- > kernel/dma/direct.c | 2 +- > 6 files changed, 10 insertions(+), 5 deletions(-) > > -- > 2.17.1.dirty ---end quoted text---