+Jani
On Tue, 2024-04-09 at 12:36 +0300, Vinod Govindapillai wrote:
> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>
> Commit 1a75cc710b95 ("iommu/vt-d: Use rbtree to track iommu probed
> devices") adds all devices probed by the iommu driver in a rbtree
> indexed by the source ID of each device. It assumes that each device
> has a unique source ID. This assumption is incorrect and the VT-d
> spec doesn't state this requirement either.
>
> The reason for using a rbtree to track devices is to look up the device
> with PCI bus and devfunc in the paths of handling ATS invalidation time
> out error and the PRI I/O page faults. Both are PCI ATS feature related.
>
> Only track the devices that have PCI ATS capabilities in the rbtree to
> avoid unnecessary WARN_ON in the iommu probe path. Otherwise, on some
> platforms below kernel splat will be displayed and the iommu probe results
> in failure.
>
> WARNING: CPU: 3 PID: 166 at drivers/iommu/intel/iommu.c:158 intel_iommu_probe_device+0x319/0xd90
> Call Trace:
> <TASK>
> ? __warn+0x7e/0x180
> ? intel_iommu_probe_device+0x319/0xd90
> ? report_bug+0x1f8/0x200
> ? handle_bug+0x3c/0x70
> ? exc_invalid_op+0x18/0x70
> ? asm_exc_invalid_op+0x1a/0x20
> ? intel_iommu_probe_device+0x319/0xd90
> ? debug_mutex_init+0x37/0x50
> __iommu_probe_device+0xf2/0x4f0
> iommu_probe_device+0x22/0x70
> iommu_bus_notifier+0x1e/0x40
> notifier_call_chain+0x46/0x150
> blocking_notifier_call_chain+0x42/0x60
> bus_notify+0x2f/0x50
> device_add+0x5ed/0x7e0
> platform_device_add+0xf5/0x240
> mfd_add_devices+0x3f9/0x500
> ? preempt_count_add+0x4c/0xa0
> ? up_write+0xa2/0x1b0
> ? __debugfs_create_file+0xe3/0x150
> intel_lpss_probe+0x49f/0x5b0
> ? pci_conf1_write+0xa3/0xf0
> intel_lpss_pci_probe+0xcf/0x110 [intel_lpss_pci]
> pci_device_probe+0x95/0x120
> really_probe+0xd9/0x370
> ? __pfx___driver_attach+0x10/0x10
> __driver_probe_device+0x73/0x150
> driver_probe_device+0x19/0xa0
> __driver_attach+0xb6/0x180
> ? __pfx___driver_attach+0x10/0x10
> bus_for_each_dev+0x77/0xd0
> bus_add_driver+0x114/0x210
> driver_register+0x5b/0x110
> ? __pfx_intel_lpss_pci_driver_init+0x10/0x10 [intel_lpss_pci]
> do_one_initcall+0x57/0x2b0
> ? kmalloc_trace+0x21e/0x280
> ? do_init_module+0x1e/0x210
> do_init_module+0x5f/0x210
> load_module+0x1d37/0x1fc0
> ? init_module_from_file+0x86/0xd0
> init_module_from_file+0x86/0xd0
> idempotent_init_module+0x17c/0x230
> __x64_sys_finit_module+0x56/0xb0
> do_syscall_64+0x6e/0x140
> entry_SYSCALL_64_after_hwframe+0x71/0x79
>
> Fixes: 1a75cc710b95 ("iommu/vt-d: Use rbtree to track iommu probed devices")
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai@xxxxxxxxx>
> ---
> drivers/iommu/intel/iommu.c | 11 +++++++----
> 1 file changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index 50eb9aed47cc..a7ecd90303dc 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -4299,9 +4299,11 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
> }
>
> dev_iommu_priv_set(dev, info);
> - ret = device_rbtree_insert(iommu, info);
> - if (ret)
> - goto free;
> + if (pdev && pci_ats_supported(pdev)) {
> + ret = device_rbtree_insert(iommu, info);
> + if (ret)
> + goto free;
> + }
>
> if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
> ret = intel_pasid_alloc_table(dev);
> @@ -4336,7 +4338,8 @@ static void intel_iommu_release_device(struct device *dev)
> struct intel_iommu *iommu = info->iommu;
>
> mutex_lock(&iommu->iopf_lock);
> - device_rbtree_remove(info);
> + if (dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev)))
> + device_rbtree_remove(info);
> mutex_unlock(&iommu->iopf_lock);
>
> if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev) &&
