From mboxrd@z Thu Jan 1 00:00:00 1970 From: okaya@codeaurora.org (Sinan Kaya) Date: Fri, 2 Mar 2018 09:12:29 -0500 Subject: RFC on Kdump and PCIe on ARM64 In-Reply-To: <20180302103032.GB19323@arm.com> References: <20180301190552.GK13722@bhelgaas-glaptop.roam.corp.google.com> <2b2de17c-8527-e49b-2ef2-2a3d1801e4f9@codeaurora.org> <20180302000303.GD74737@bhelgaas-glaptop.roam.corp.google.com> <20180302103032.GB19323@arm.com> Message-ID: <84121a8d-5294-0567-6c6b-f57e85dc4961@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Will, On 3/2/2018 5:30 AM, Will Deacon wrote: >> Do you really have to reset the IOMMU? Can you just give it new page >> tables that start out with all IOVAs from all devices being invalid, >> then add valid mappings as drivers need them (presumably after the >> driver has done whatever it needs to so the device stops using the old >> DMA addresses)? > We already have the option to do that via the command line using the > disable_bypass option, so it just sounds like we need to take this into > account when resetting the SMMU to take care that GBPA is configured so > that transactions are terminated when SMMUEN=0. How about the points that Baoquan highlighted in his email regarding the solution from AMD and X86? I have not read the entire thread but, is this just a matter of following what Bjorn recommended or there is more to it? Sinan -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.