On 2017/11/3 17:37, Jean-Philippe Brucker wrote: > 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? > Yes, it will be more clear. Thanks Yisheng > Thanks, > Jean > > . >
