Hi Hi, Zhangfei, On 5/10/22 05:17, Yi Liu wrote: > Hi Zhangfei, > > On 2022/5/9 22:24, Zhangfei Gao wrote: >> Hi, Alex >> >> On 2022/4/27 上午12:35, Alex Williamson wrote: >>> On Tue, 26 Apr 2022 12:43:35 +0000 >>> Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx> wrote: >>> >>>>> -----Original Message----- >>>>> From: Eric Auger [mailto:eric.auger@xxxxxxxxxx] >>>>> Sent: 26 April 2022 12:45 >>>>> To: Shameerali Kolothum Thodi >>>>> <shameerali.kolothum.thodi@xxxxxxxxxx>; Yi >>>>> Liu <yi.l.liu@xxxxxxxxx>; alex.williamson@xxxxxxxxxx; >>>>> cohuck@xxxxxxxxxx; >>>>> qemu-devel@xxxxxxxxxx >>>>> Cc: david@xxxxxxxxxxxxxxxxxxxxx; thuth@xxxxxxxxxx; >>>>> farman@xxxxxxxxxxxxx; >>>>> mjrosato@xxxxxxxxxxxxx; akrowiak@xxxxxxxxxxxxx; pasic@xxxxxxxxxxxxx; >>>>> jjherne@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; >>>>> jgg@xxxxxxxxxx; nicolinc@xxxxxxxxxx; eric.auger.pro@xxxxxxxxx; >>>>> kevin.tian@xxxxxxxxx; chao.p.peng@xxxxxxxxx; yi.y.sun@xxxxxxxxx; >>>>> peterx@xxxxxxxxxx; Zhangfei Gao <zhangfei.gao@xxxxxxxxxx> >>>>> Subject: Re: [RFC 00/18] vfio: Adopt iommufd >>>> [...] >>>>> https://lore.kernel.org/kvm/0-v1-e79cd8d168e8+6-iommufd_jgg@xxxxxxxxxx >>>>> >>>>>>> / >>>>>>> [2] https://github.com/luxis1999/iommufd/tree/iommufd-v5.17-rc6 >>>>>>> [3] >>>>>>> https://github.com/luxis1999/qemu/tree/qemu-for-5.17-rc6-vm-rfcv1 >>>>>> Hi, >>>>>> >>>>>> I had a go with the above branches on our ARM64 platform trying to >>>>> pass-through >>>>>> a VF dev, but Qemu reports an error as below, >>>>>> >>>>>> [ 0.444728] hisi_sec2 0000:00:01.0: enabling device (0000 -> >>>>>> 0002) >>>>>> qemu-system-aarch64-iommufd: IOMMU_IOAS_MAP failed: Bad address >>>>>> qemu-system-aarch64-iommufd: vfio_container_dma_map(0xaaaafeb40ce0, >>>>> 0x8000000000, 0x10000, 0xffffb40ef000) = -14 (Bad address) >>>>>> I think this happens for the dev BAR addr range. I haven't >>>>>> debugged the >>>>> kernel >>>>>> yet to see where it actually reports that. >>>>> Does it prevent your assigned device from working? I have such errors >>>>> too but this is a known issue. This is due to the fact P2P DMA is not >>>>> supported yet. >>>> Yes, the basic tests all good so far. I am still not very clear how >>>> it works if >>>> the map() fails though. It looks like it fails in, >>>> >>>> iommufd_ioas_map() >>>> iopt_map_user_pages() >>>> iopt_map_pages() >>>> .. >>>> pfn_reader_pin_pages() >>>> >>>> So does it mean it just works because the page is resident()? >>> No, it just means that you're not triggering any accesses that require >>> peer-to-peer DMA support. Any sort of test where the device is only >>> performing DMA to guest RAM, which is by far the standard use case, >>> will work fine. This also doesn't affect vCPU access to BAR space. >>> It's only a failure of the mappings of the BAR space into the IOAS, >>> which is only used when a device tries to directly target another >>> device's BAR space via DMA. Thanks, >> >> I also get this issue when trying adding prereg listenner >> >> + container->prereg_listener = vfio_memory_prereg_listener; >> + memory_listener_register(&container->prereg_listener, >> + &address_space_memory); >> >> host kernel log: >> iommufd_ioas_map 1 iova=8000000000, iova1=8000000000, >> cmd->iova=8000000000, cmd->user_va=9c495000, cmd->length=10000 >> iopt_alloc_area input area=859a2d00 iova=8000000000 >> iopt_alloc_area area=859a2d00 iova=8000000000 >> pin_user_pages_remote rc=-14 >> >> qemu log: >> vfio_prereg_listener_region_add >> iommufd_map iova=0x8000000000 >> qemu-system-aarch64: IOMMU_IOAS_MAP failed: Bad address >> qemu-system-aarch64: vfio_dma_map(0xaaaafb96a930, 0x8000000000, >> 0x10000, 0xffff9c495000) = -14 (Bad address) >> qemu-system-aarch64: (null) >> double free or corruption (fasttop) >> Aborted (core dumped) >> >> With hack of ignoring address 0x8000000000 in map and unmap, kernel >> can boot. > > do you know if the iova 0x8000000000 guest RAM or MMIO? Currently, > iommufd kernel part doesn't support mapping device BAR MMIO. This is a > known gap. In qemu arm virt machine this indeed matches the PCI MMIO region. Thanks Eric
