Hi Eric, >-----Original Message----- >From: Eric Auger <eric.auger@redhat.com> >Sent: Friday, June 24, 2022 12:52 AM >To: Duan, Zhenzhong <zhenzhong.duan@intel.com> >Cc: qemu-devel@nongnu.org; mst@redhat.com; jean-philippe@linaro.org; >pbonzini@redhat.com; Zhang, Yu C <yu.c.zhang@intel.com>; Dong, >Chuanxiao <chuanxiao.dong@intel.com>; Zhang, Tina ><tina.zhang@intel.com> >Subject: Re: [PATCH 0/3] Add bypass mode support to assigned device > >Hi Duan, > >On 6/13/22 08:10, Zhenzhong Duan wrote: >> Currently virtio-iommu's logic to support bypass mode works only for >> emulated device. For assigned device, no GPA -> HPA mapping is setup >> in IOMMU page table. >> >> Host report below error: >> [3713481.750944] dmar_fault: 191 callbacks suppressed [3713481.750953] >> DMAR: DRHD: handling fault status reg 302 [3713481.750962] DMAR: [DMA >> Read NO_PASID] Request device [2f:00.1] fault addr 0x7ebb0000 [fault >> reason 0x06] PTE Read access is not set [3713481.751003] DMAR: DRHD: >> handling fault status reg 402 [3713481.751007] DMAR: [DMA Read >> NO_PASID] Request device [2f:00.1] fault addr 0x7ebb0000 [fault reason >> 0x06] PTE Read access is not set [3713481.751023] DMAR: DRHD: handling >> fault status reg 502 [3713481.751026] DMAR: [DMA Write NO_PASID] >> Request device [2f:00.1] fault addr 0x7ebb0000 [fault reason 0x05] PTE >> Write access is not set [3713481.751072] DMAR: DRHD: handling fault >> status reg 602 >> >> Guest kernel report below error: >> [ 3.461716] i40e: Intel(R) Ethernet Connection XL710 Network Driver >> [ 3.462605] i40e: Copyright (c) 2013 - 2019 Intel Corporation. >> [ 3.464630] i40e 0000:00:04.0: Adding to iommu group 5 >> [ 3.482093] i40e 0000:00:04.0: fw 0.0.00000 api 0.0 nvm 0.00 0x176953ce >28.50.1 [8086:37d3] [8086:35d0] >> [ 3.484295] i40e 0000:00:04.0: eeprom check failed (-62), Tx/Rx traffic >disabled >> [ 3.487268] i40e 0000:00:04.0: configure_lan_hmc failed: -49 >> [ 3.489066] i40e: probe of 0000:00:04.0 failed with error -2 >> >> Fix it by adding switch beween bypass and iommu address space just >> like the virtual VT-d implementation, so that in bypass mode, vfio >> mapping is setup. >> >> Tested with four combination of qemu's >> virtio-iommu.boot-bypass=true/false >> with guest kernel's iommu=pt/nopt on x86_64 platform. > >I know this has already landed uptream (I was off last week) but I have few >comments/questions related to the series. Sure😊 >> >> Zhenzhong Duan (3): >> virtio-iommu: Add bypass mode support to assigned device >> virtio-iommu: Use recursive lock to avoid deadlock >This patch may have been squashed into the previous one, as >"virtio-iommu: Add bypass mode support to assigned device" deadlocks. Yes, that may be better. My initial thought is to make 1st patch slim a bit, which may be more clear for maintainers to review. Thanks Zhenzhong
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