> -----Original Message----- > From: Eric Auger [mailto:eric.auger@xxxxxxxxxx] > Sent: 07 December 2021 11:06 > To: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>; eric.auger.pro@xxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx; kvmarm@xxxxxxxxxxxxxxxxxxxxx; joro@xxxxxxxxxx; > will@xxxxxxxxxx; robin.murphy@xxxxxxx; jean-philippe@xxxxxxxxxx; > zhukeqian <zhukeqian1@xxxxxxxxxx> > Cc: alex.williamson@xxxxxxxxxx; jacob.jun.pan@xxxxxxxxxxxxxxx; > yi.l.liu@xxxxxxxxx; kevin.tian@xxxxxxxxx; ashok.raj@xxxxxxxxx; > maz@xxxxxxxxxx; peter.maydell@xxxxxxxxxx; vivek.gautam@xxxxxxx; > Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; > wangxingang <wangxingang5@xxxxxxxxxx>; jiangkunkun > <jiangkunkun@xxxxxxxxxx>; yuzenghui <yuzenghui@xxxxxxxxxx>; > nicoleotsuka@xxxxxxxxx; chenxiang (M) <chenxiang66@xxxxxxxxxxxxx>; > sumitg@xxxxxxxxxx; nicolinc@xxxxxxxxxx; vdumpa@xxxxxxxxxx; > zhangfei.gao@xxxxxxxxx; lushenming@xxxxxxxxxx; vsethi@xxxxxxxxxx > Subject: Re: [RFC v16 0/9] SMMUv3 Nested Stage Setup (IOMMU part) > > Hi Zhangfei, > > On 12/7/21 11:35 AM, Zhangfei Gao wrote: > > > > > > On 2021/12/7 下午6:27, Eric Auger wrote: > >> Hi Zhangfei, > >> > >> On 12/3/21 1:27 PM, Zhangfei Gao wrote: > >>> Hi, Eric > >>> > >>> On 2021/10/27 下午6:44, Eric Auger wrote: > >>>> This series brings the IOMMU part of HW nested paging support > >>>> in the SMMUv3. > >>>> > >>>> The SMMUv3 driver is adapted to support 2 nested stages. > >>>> > >>>> The IOMMU API is extended to convey the guest stage 1 > >>>> configuration and the hook is implemented in the SMMUv3 driver. > >>>> > >>>> This allows the guest to own the stage 1 tables and context > >>>> descriptors (so-called PASID table) while the host owns the > >>>> stage 2 tables and main configuration structures (STE). > >>>> > >>>> This work mainly is provided for test purpose as the upper > >>>> layer integration is under rework and bound to be based on > >>>> /dev/iommu instead of VFIO tunneling. In this version we also get > >>>> rid of the MSI BINDING ioctl, assuming the guest enforces > >>>> flat mapping of host IOVAs used to bind physical MSI doorbells. > >>>> In the current QEMU integration this is achieved by exposing > >>>> RMRs to the guest, using Shameer's series [1]. This approach > >>>> is RFC as the IORT spec is not really meant to do that > >>>> (single mapping flag limitation). > >>>> > >>>> Best Regards > >>>> > >>>> Eric > >>>> > >>>> This series (Host) can be found at: > >>>> https://github.com/eauger/linux/tree/v5.15-rc7-nested-v16 > >>>> This includes a rebased VFIO integration (although not meant > >>>> to be upstreamed) > >>>> > >>>> Guest kernel branch can be found at: > >>>> https://github.com/eauger/linux/tree/shameer_rmrr_v7 > >>>> featuring [1] > >>>> > >>>> QEMU integration (still based on VFIO and exposing RMRs) > >>>> can be found at: > >>>> > https://github.com/eauger/qemu/tree/v6.1.0-rmr-v2-nested_smmuv3_v10 > >>>> (use iommu=nested-smmuv3 ARM virt option) > >>>> > >>>> Guest dependency: > >>>> [1] [PATCH v7 0/9] ACPI/IORT: Support for IORT RMR node > >>> Thanks a lot for upgrading these patches. > >>> > >>> I have basically verified these patches on HiSilicon Kunpeng920. > >>> And integrated them to these branches. > >>> https://github.com/Linaro/linux-kernel-uadk/tree/uacce-devel-5.16 > >>> https://github.com/Linaro/qemu/tree/v6.1.0-rmr-v2-nested_smmuv3_v10 > >>> > >>> Though they are provided for test purpose, > >>> > >>> Tested-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx> > >> Thank you very much. As you mentioned, until we do not have the > >> /dev/iommu integration this is maintained for testing purpose. The SMMU > >> changes shouldn't be much impacted though. > >> The added value of this respin was to propose an MSI binding solution > >> based on RMRRs which simplify things at kernel level. > > > > Current RMRR solution requires uefi enabled, > > and QEMU_EFI.fd has to be provided to start qemu. > > > > Any plan to support dtb as well, which will be simpler since no need > > QEMU_EFI.fd anymore. > Yes the solution is based on ACPI IORT nodes. No clue if some DT > integration is under work. Shameer? There was some attempt in the past to create identity mappings using DT. This is the latest I can find on it, https://lore.kernel.org/linux-iommu/YTelDHx2REIIvV%2FN@xxxxxxxxxxxxxxx/T/ Thanks, Shameer
