> -----Original Message----- > From: Jean-Philippe Brucker [mailto:jean-philippe.brucker@xxxxxxx] > Sent: Friday, November 03, 2017 9:37 AM > To: xieyisheng (A) <xieyisheng1@xxxxxxxxxx>; Shameerali Kolothum Thodi > <shameerali.kolothum.thodi@xxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux- > acpi@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; iommu@lists.linux- > foundation.org; Mark Rutland <Mark.Rutland@xxxxxxx>; Gabriele Paoloni > <gabriele.paoloni@xxxxxxxxxx>; Catalin Marinas > <Catalin.Marinas@xxxxxxx>; Will Deacon <Will.Deacon@xxxxxxx>; > okaya@xxxxxxxxxxxxxx; yi.l.liu@xxxxxxxxx; Lorenzo Pieralisi > <Lorenzo.Pieralisi@xxxxxxx>; ashok.raj@xxxxxxxxx; tn@xxxxxxxxxxxx; > joro@xxxxxxxxxx; rfranz@xxxxxxxxxx; lenb@xxxxxxxxxx; > jacob.jun.pan@xxxxxxxxxxxxxxx; alex.williamson@xxxxxxxxxx; > robh+dt@xxxxxxxxxx; Leizhen (ThunderTown) <thunder.leizhen@xxxxxxxxxx>; > bhelgaas@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx; liubo (CU) > <liubo95@xxxxxxxxxx>; rjw@xxxxxxxxxxxxx; robdclark@xxxxxxxxx; > hanjun.guo@xxxxxxxxxx; Sudeep Holla <Sudeep.Holla@xxxxxxx>; Robin > Murphy <Robin.Murphy@xxxxxxx>; nwatters@xxxxxxxxxxxxxx; Linuxarm > <linuxarm@xxxxxxxxxx> > Subject: Re: [RFCv2 PATCH 14/36] iommu/arm-smmu-v3: Add support for > Substream IDs > > On 03/11/17 05:45, Yisheng Xie wrote: > > Hi Jean, > > > > On 2017/11/3 1:02, Shameerali Kolothum Thodi wrote: > >> > >> > >>> -----Original Message----- > >>> From: Jean-Philippe Brucker [mailto:Jean-Philippe.Brucker@xxxxxxx] > >>> Sent: Thursday, November 02, 2017 3:52 PM > >>> To: Shameerali Kolothum Thodi > <shameerali.kolothum.thodi@xxxxxxxxxx> > >>> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux- > >>> acpi@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; iommu@lists.linux- > >>> foundation.org; Mark Rutland <Mark.Rutland@xxxxxxx>; xieyisheng (A) > >>> <xieyisheng1@xxxxxxxxxx>; Gabriele Paoloni > >>> <gabriele.paoloni@xxxxxxxxxx>; Catalin Marinas > >>> <Catalin.Marinas@xxxxxxx>; Will Deacon <Will.Deacon@xxxxxxx>; > >>> okaya@xxxxxxxxxxxxxx; yi.l.liu@xxxxxxxxx; Lorenzo Pieralisi > >>> <Lorenzo.Pieralisi@xxxxxxx>; ashok.raj@xxxxxxxxx; tn@xxxxxxxxxxxx; > >>> joro@xxxxxxxxxx; rfranz@xxxxxxxxxx; lenb@xxxxxxxxxx; > >>> jacob.jun.pan@xxxxxxxxxxxxxxx; alex.williamson@xxxxxxxxxx; > >>> robh+dt@xxxxxxxxxx; Leizhen (ThunderTown) > <thunder.leizhen@xxxxxxxxxx>; > >>> bhelgaas@xxxxxxxxxx; dwmw2@xxxxxxxxxxxxx; liubo (CU) > >>> <liubo95@xxxxxxxxxx>; rjw@xxxxxxxxxxxxx; robdclark@xxxxxxxxx; > >>> hanjun.guo@xxxxxxxxxx; Sudeep Holla <Sudeep.Holla@xxxxxxx>; Robin > >>> Murphy <Robin.Murphy@xxxxxxx>; nwatters@xxxxxxxxxxxxxx; Linuxarm > >>> <linuxarm@xxxxxxxxxx> > >>> Subject: Re: [RFCv2 PATCH 14/36] iommu/arm-smmu-v3: Add support for > >>> Substream IDs > >>> > >>> Hi Shameer, > >>> > >>> On Thu, Nov 02, 2017 at 12:49:32PM +0000, Shameerali Kolothum Thodi > wrote: > >>>> We had a go with this series on HiSIlicon D05 platform which doesn't have > >>>> support for ssids/ATS/PRI, to make sure it generally works. > >>>> > >>>> But observed the below crash on boot, > >>>> > >>>> [ 16.009084] WARNING: CPU: 59 PID: 391 at mm/page_alloc.c:3883 > >>> __alloc_pages_nodemask+0x19c/0xc48 > >>>> [ 16.026797] Modules linked in: > >>>> [ 16.032944] CPU: 59 PID: 391 Comm: kworker/59:1 Not tainted 4.14.0- > rc1- > >>> 159539-ge42aca3 #236 > >>>> [...] > >>>> [ 16.068206] Workqueue: events deferred_probe_work_func > >>>> [ 16.078557] task: ffff8017d38a0000 task.stack: ffff00000b198000 > >>>> [ 16.090486] PC is at __alloc_pages_nodemask+0x19c/0xc48 > >>>> [ 16.101013] LR is at __alloc_pages_nodemask+0xe0/0xc48 > >>>> [ 16.469220] [<ffff000008186b94>] > __alloc_pages_nodemask+0x19c/0xc48 > >>>> [ 16.481854] [<ffff0000081d65b0>] alloc_pages_current+0x80/0xcc > >>>> [ 16.493607] [<ffff000008182be8>] __get_free_pages+0xc/0x38 > >>>> [ 16.504661] [<ffff0000083c4d58>] swiotlb_alloc_coherent+0x64/0x190 > >>>> [ 16.517117] [<ffff00000809824c>] __dma_alloc+0x110/0x204 > >>>> [ 16.527820] [<ffff00000858e850>] dmam_alloc_coherent+0x88/0xf0 > >>>> [ 16.539575] [<ffff000008568884>] > >>> arm_smmu_domain_finalise_s1+0x60/0x248 > >>>> [ 16.552909] [<ffff00000856c104>] > arm_smmu_attach_dev+0x264/0x300 > >>>> [ 16.565013] [<ffff00000855d40c>] __iommu_attach_device+0x48/0x5c > >>>> [ 16.577117] [<ffff00000855e698>] > iommu_group_add_device+0x144/0x3a4 > >>>> [ 16.589746] [<ffff00000855ed18>] > iommu_group_get_for_dev+0x70/0xf8 > >>>> [ 16.602201] [<ffff00000856a314>] > arm_smmu_add_device+0x1a4/0x418 > >>>> [ 16.614308] [<ffff00000849dfcc>] iort_iommu_configure+0xf0/0x16c > >>>> [ 16.626416] [<ffff000008468c50>] acpi_dma_configure+0x30/0x70 > >>>> [ 16.637994] [<ffff00000858f00c>] dma_configure+0xa8/0xd4 > >>>> [ 16.648695] [<ffff00000857706c>] driver_probe_device+0x1a4/0x2dc > >>>> [ 16.673081] [<ffff0000085752c8>] bus_for_each_drv+0x54/0x94 > >>>> [ 16.684307] [<ffff000008576db0>] __device_attach+0xc4/0x12c > >>>> [ 16.695533] [<ffff000008577350>] device_initial_probe+0x10/0x18 > >>>> [ 16.707462] [<ffff0000085762b4>] bus_probe_device+0x90/0x98 > >>>> > >>>> After a bit of debug it looks like on platforms where ssid is not supported, > >>>> s1_cfg.num_contexts is set to zero and it eventually results in this crash > >>>> in, > >>>> arm_smmu_domain_finalise_s1() -->arm_smmu_alloc_cd_tables()--> > >>>> arm_smmu_alloc_cd_leaf_table() as num_leaf_entries is zero. > >>>> > >>>> With the below fix, it works on D05 now, > >>>> > >>>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu- > v3.c > >>>> index 8ad90e2..51f5821 100644 > >>>> --- a/drivers/iommu/arm-smmu-v3.c > >>>> +++ b/drivers/iommu/arm-smmu-v3.c > >>>> @@ -2433,7 +2433,10 @@ static int arm_smmu_domain_finalise(struct > >>> iommu_domain *domain, > >>>> domain->min_pasid = 1; > >>>> domain->max_pasid = master->num_ssids - 1; > >>>> smmu_domain->s1_cfg.num_contexts = master- > >num_ssids; > >>>> + } else { > >>>> + smmu_domain->s1_cfg.num_contexts = 1; > >>>> } > >>>> + > >>>> smmu_domain->s1_cfg.can_stall = master->ste.can_stall; > >>>> break; > >>>> case ARM_SMMU_DOMAIN_NESTED: > >>>> > >>>> > >>>> I am not sure this is right place do this. Please take a look. > >>> > >>> Thanks for testing the series and reporting the bug. I added the > >>> following patch to branch svm/current, does it work for you? > >> > >> Yes, it does. > >> > >> Thanks, > >> Shameer > >> > >>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu- > v3.c > >>> index 42c8378624ed..edda466adc81 100644 > >>> --- a/drivers/iommu/arm-smmu-v3.c > >>> +++ b/drivers/iommu/arm-smmu-v3.c > >>> @@ -3169,9 +3169,7 @@ static int arm_smmu_add_device(struct device > *dev) > >>> } > >>> } > >>> > >>> - if (smmu->ssid_bits) > >>> - master->num_ssids = 1 << min(smmu->ssid_bits, > >>> - fwspec->num_pasid_bits); > >>> + master->num_ssids = 1 << min(smmu->ssid_bits, fwspec- > >>>> num_pasid_bits); > > > > If fwspec->num_pasid_bits = 0, then master have _one_ num_ssids ? > > Yes, the context table allocator always needs to allocate at least one > entry, even if the master or SMMU doesn't support SSID. I think an earlier > version called this field "num_contexts", maybe we should got back to that > name for clarity? +1 for that. As ssid can be zero as per the spec, num_ssids=1 will be slightly misleading. Thanks, Shameer
