From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 2 Oct 2017 11:21:29 -0600 From: Keith Busch To: Christoph Hellwig Cc: Abhishek Shah , Jens Axboe , Sagi Grimberg , linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, stable@vger.kernel.org Subject: Re: [PATCH v2] nvme-pci: Use PCI bus address for data/queues in CMB Message-ID: <20171002172128.GV8463@localhost.localdomain> References: <1506763722-10687-1-git-send-email-abhishek.shah@broadcom.com> <20171001074203.GA11115@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171001074203.GA11115@lst.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Sun, Oct 01, 2017 at 09:42:03AM +0200, Christoph Hellwig wrote: > This looks very convoluted, mostly because the existing code is > doing weird things. For one thing what is sq_dma_addr currently > is not a DMA adddress - we either need the resource address > for the ioremap, but we don't need to stash that away, and second > the one programmed into the controller should be a pci_bus_addr_t. > > Second we already have a nice PCI-layer helper called pci_bus_address > to get the bus address for us and we should use it. > > Something like the patch below should solve the issue: Yah, calling this a DMA address was a misnomer and confusing. > --- > From b78f4164881125c4fecfdb87878d0120b2177c53 Mon Sep 17 00:00:00 2001 > From: Christoph Hellwig > Date: Sun, 1 Oct 2017 09:37:35 +0200 > Subject: nvme-pci: Use PCI bus address for data/queues in CMB > > Currently, NVMe PCI host driver is programming CMB dma address as > I/O SQs addresses. This results in failures on systems where 1:1 > outbound mapping is not used (example Broadcom iProc SOCs) because > CMB BAR will be progammed with PCI bus address but NVMe PCI EP will > try to access CMB using dma address. > > To have CMB working on systems without 1:1 outbound mapping, we > program PCI bus address for I/O SQs instead of dma address. This > approach will work on systems with/without 1:1 outbound mapping. > > Based on a report and previous patch from Abhishek Shah. > > Fixes: 8ffaadf7 ("NVMe: Use CMB for the IO SQes if available") > Cc: stable@vger.kernel.org > Reported-by: Abhishek Shah > Signed-off-by: Christoph Hellwig This looks good. Reviewed-by: Keith Busch