Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753013AbcLKCGJ (ORCPT ); Sat, 10 Dec 2016 21:06:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52126 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751674AbcLKCF7 (ORCPT ); Sat, 10 Dec 2016 21:05:59 -0500 Subject: Re: [RFC v3 00/10] KVM PCIe/MSI passthrough on ARM/ARM64 and IOVA reserved regions To: Auger Eric , eric.auger.pro@gmail.com, christoffer.dall@linaro.org, marc.zyngier@arm.com, robin.murphy@arm.com, alex.williamson@redhat.com, will.deacon@arm.com, joro@8bytes.org, tglx@linutronix.de, jason@lakedaemon.net, linux-arm-kernel@lists.infradead.org References: <1479215363-2898-1-git-send-email-eric.auger@redhat.com> Cc: kvm@vger.kernel.org, drjones@redhat.com, linux-kernel@vger.kernel.org, pranav.sawargaonkar@gmail.com, iommu@lists.linux-foundation.org, punit.agrawal@arm.com, diana.craciun@nxp.com From: Don Dutile Message-ID: <584CB481.3040902@redhat.com> Date: Sat, 10 Dec 2016 21:05:53 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Sun, 11 Dec 2016 02:05:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4099 Lines: 106 On 12/08/2016 04:36 AM, Auger Eric wrote: > Hi, > > On 15/11/2016 14:09, Eric Auger wrote: >> Following LPC discussions, we now report reserved regions through >> iommu-group sysfs reserved_regions attribute file. > > > While I am respinning this series into v4, here is a tentative summary > of technical topics for which no consensus was reached at this point. > > 1) Shall we report the usable IOVA range instead of reserved IOVA > ranges. Not discussed at/after LPC. > x I currently report reserved regions. Alex expressed the need to > report the full usable IOVA range instead (x86 min-max range > minus MSI APIC window). I think this is meaningful for ARM > too where arm-smmu might not support the full 64b range. > x Any objection we report the usable IOVA regions instead? > > 2) Shall the kernel check collision with MSI window* when userspace > calls VFIO_IOMMU_MAP_DMA? > Joerg/Will No; Alex yes > *for IOVA regions consumed downstream to the IOMMU: everyone says NO > > 3) RMRR reporting in the iommu group sysfs? Joerg: yes; Don: no Um, I'm missing context, but the only thing I recall saying no to wrt RMRR is that _any_ device that has an RMRR cannot be assigned to a guest. Or, are you saying, RMRR's should be exposed in the guest os? if so, then you have my 'no' there. > My current series does not expose them in iommu group sysfs. > I understand we can expose the RMRR regions in the iomm group sysfs > without necessarily supporting RMRR requiring device assignment. This sentence doesn't make sense to me. Can you try re-wording it? I can't tell what RMRR has to do w/device assignment, other than what I said above. Exposing RMRR's in sysfs is not an issue in general. > We can also add this support later. > > Thanks > > Eric > > >> >> Reserved regions are populated through the IOMMU get_resv_region callback >> (former get_dm_regions), now implemented by amd-iommu, intel-iommu and >> arm-smmu. >> >> The intel-iommu reports the [FEE0_0000h - FEF0_000h] MSI window as an >> IOMMU_RESV_NOMAP reserved region. >> >> arm-smmu reports the MSI window (arbitrarily located at 0x8000000 and >> 1MB large) and the PCI host bridge windows. >> >> The series integrates a not officially posted patch from Robin: >> "iommu/dma: Allow MSI-only cookies". >> >> This series currently does not address IRQ safety assessment. >> >> Best Regards >> >> Eric >> >> Git: complete series available at >> https://github.com/eauger/linux/tree/v4.9-rc5-reserved-rfc-v3 >> >> History: >> RFC v2 -> v3: >> - switch to an iommu-group sysfs API >> - use new dummy allocator provided by Robin >> - dummy allocator initialized by vfio-iommu-type1 after enumerating >> the reserved regions >> - at the moment ARM MSI base address/size is left unchanged compared >> to v2 >> - we currently report reserved regions and not usable IOVA regions as >> requested by Alex >> >> RFC v1 -> v2: >> - fix intel_add_reserved_regions >> - add mutex lock/unlock in vfio_iommu_type1 >> >> >> Eric Auger (10): >> iommu/dma: Allow MSI-only cookies >> iommu: Rename iommu_dm_regions into iommu_resv_regions >> iommu: Add new reserved IOMMU attributes >> iommu: iommu_alloc_resv_region >> iommu: Do not map reserved regions >> iommu: iommu_get_group_resv_regions >> iommu: Implement reserved_regions iommu-group sysfs file >> iommu/vt-d: Implement reserved region get/put callbacks >> iommu/arm-smmu: Implement reserved region get/put callbacks >> vfio/type1: Get MSI cookie >> >> drivers/iommu/amd_iommu.c | 20 +++--- >> drivers/iommu/arm-smmu.c | 52 +++++++++++++++ >> drivers/iommu/dma-iommu.c | 116 ++++++++++++++++++++++++++------- >> drivers/iommu/intel-iommu.c | 50 ++++++++++---- >> drivers/iommu/iommu.c | 141 ++++++++++++++++++++++++++++++++++++---- >> drivers/vfio/vfio_iommu_type1.c | 26 ++++++++ >> include/linux/dma-iommu.h | 7 ++ >> include/linux/iommu.h | 49 ++++++++++---- >> 8 files changed, 391 insertions(+), 70 deletions(-) >>