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Message-ID: <a275032f-cb1d-4ccc-9418-9567aba6b343@linux.intel.com>
Date: Tue, 19 Dec 2023 14:49:39 +0800
From: Ethan Zhao <haifeng.zhao@...ux.intel.com>
To: Baolu Lu <baolu.lu@...ux.intel.com>, bhelgaas@...gle.com,
dwmw2@...radead.org, will@...nel.org, robin.murphy@....com, lukas@...ner.de
Cc: linux-pci@...r.kernel.org, iommu@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] iommu/vt-d: don's issue devTLB flush request when
device is disconnected
On 12/19/2023 2:09 PM, Baolu Lu wrote:
> On 2023/12/17 19:49, Ethan Zhao wrote:
>> For those endpoint devices connect to system via hotplug capable ports,
>> users could request a warm reset to the device by flapping device's link
>> through setting the slot's link control register, as pciehpt_ist() DLLSC
>> interrupt sequence response, pciehp will unload the device driver and
>> then power it off. thus cause an IOMMU devTLB flush request for
>> device to
>> be sent and a long time completion/timeout waiting in interrupt context.
>>
>> That would cause following continuous hard lockup warning and system
>> hang
>>
>> [ 4211.433662] pcieport 0000:17:01.0: pciehp: Slot(108): Link Down
>> [ 4211.433664] pcieport 0000:17:01.0: pciehp: Slot(108): Card not
>> present
>> [ 4223.822591] NMI watchdog: Watchdog detected hard LOCKUP on cpu 144
>> [ 4223.822622] CPU: 144 PID: 1422 Comm: irq/57-pciehp Kdump: loaded
>> Tainted: G S
>> OE kernel version xxxx
>> [ 4223.822623] Hardware name: vendorname xxxx 666-106,
>> BIOS 01.01.02.03.01 05/15/2023
>> [ 4223.822623] RIP: 0010:qi_submit_sync+0x2c0/0x490
>> [ 4223.822624] Code: 48 be 00 00 00 00 00 08 00 00 49 85 74 24 20 0f
>> 95 c1 48 8b
>> 57 10 83 c1 04 83 3c 1a 03 0f 84 a2 01 00 00 49 8b 04 24 8b 70 34
>> <40> f6 c6 1
>> 0 74 17 49 8b 04 24 8b 80 80 00 00 00 89 c2 d3 fa 41 39
>> [ 4223.822624] RSP: 0018:ffffc4f074f0bbb8 EFLAGS: 00000093
>> [ 4223.822625] RAX: ffffc4f040059000 RBX: 0000000000000014 RCX:
>> 0000000000000005
>> [ 4223.822625] RDX: ffff9f3841315800 RSI: 0000000000000000 RDI:
>> ffff9f38401a8340
>> [ 4223.822625] RBP: ffff9f38401a8340 R08: ffffc4f074f0bc00 R09:
>> 0000000000000000
>> [ 4223.822626] R10: 0000000000000010 R11: 0000000000000018 R12:
>> ffff9f384005e200
>> [ 4223.822626] R13: 0000000000000004 R14: 0000000000000046 R15:
>> 0000000000000004
>> [ 4223.822626] FS: 0000000000000000(0000) GS:ffffa237ae400000(0000)
>> knlGS:0000000000000000
>> [ 4223.822627] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 4223.822627] CR2: 00007ffe86515d80 CR3: 000002fd3000a001 CR4:
>> 0000000000770ee0
>> [ 4223.822627] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
>> 0000000000000000
>> [ 4223.822628] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7:
>> 0000000000000400
>> [ 4223.822628] PKRU: 55555554
>> [ 4223.822628] Call Trace:
>> [ 4223.822628] qi_flush_dev_iotlb+0xb1/0xd0
>> [ 4223.822628] __dmar_remove_one_dev_info+0x224/0x250
>> [ 4223.822629] dmar_remove_one_dev_info+0x3e/0x50
>> [ 4223.822629] intel_iommu_release_device+0x1f/0x30
>> [ 4223.822629] iommu_release_device+0x33/0x60
>> [ 4223.822629] iommu_bus_notifier+0x7f/0x90
>> [ 4223.822630] blocking_notifier_call_chain+0x60/0x90
>> [ 4223.822630] device_del+0x2e5/0x420
>> [ 4223.822630] pci_remove_bus_device+0x70/0x110
>> [ 4223.822630] pciehp_unconfigure_device+0x7c/0x130
>> [ 4223.822631] pciehp_disable_slot+0x6b/0x100
>> [ 4223.822631] pciehp_handle_presence_or_link_change+0xd8/0x320
>> [ 4223.822631] pciehp_ist+0x176/0x180
>> [ 4223.822631] ? irq_finalize_oneshot.part.50+0x110/0x110
>> [ 4223.822632] irq_thread_fn+0x19/0x50
>> [ 4223.822632] irq_thread+0x104/0x190
>> [ 4223.822632] ? irq_forced_thread_fn+0x90/0x90
>> [ 4223.822632] ? irq_thread_check_affinity+0xe0/0xe0
>> [ 4223.822633] kthread+0x114/0x130
>> [ 4223.822633] ? __kthread_cancel_work+0x40/0x40
>> [ 4223.822633] ret_from_fork+0x1f/0x30
>> [ 4223.822633] Kernel panic - not syncing: Hard LOCKUP
>> [ 4223.822634] CPU: 144 PID: 1422 Comm: irq/57-pciehp Kdump: loaded
>> Tainted: G S
>> OE kernel version xxxx
>> [ 4223.822634] Hardware name: vendorname xxxx 666-106,
>> BIOS 01.01.02.03.01 05/15/2023
>> [ 4223.822634] Call Trace:
>> [ 4223.822634] <NMI>
>> [ 4223.822635] dump_stack+0x6d/0x88
>> [ 4223.822635] panic+0x101/0x2d0
>> [ 4223.822635] ? ret_from_fork+0x11/0x30
>> [ 4223.822635] nmi_panic.cold.14+0xc/0xc
>> [ 4223.822636] watchdog_overflow_callback.cold.8+0x6d/0x81
>> [ 4223.822636] __perf_event_overflow+0x4f/0xf0
>> [ 4223.822636] handle_pmi_common+0x1ef/0x290
>> [ 4223.822636] ? __set_pte_vaddr+0x28/0x40
>> [ 4223.822637] ? flush_tlb_one_kernel+0xa/0x20
>> [ 4223.822637] ? __native_set_fixmap+0x24/0x30
>> [ 4223.822637] ? ghes_copy_tofrom_phys+0x70/0x100
>> [ 4223.822637] ? __ghes_peek_estatus.isra.16+0x49/0xa0
>> [ 4223.822637] intel_pmu_handle_irq+0xba/0x2b0
>> [ 4223.822638] perf_event_nmi_handler+0x24/0x40
>> [ 4223.822638] nmi_handle+0x4d/0xf0
>> [ 4223.822638] default_do_nmi+0x49/0x100
>> [ 4223.822638] exc_nmi+0x134/0x180
>> [ 4223.822639] end_repeat_nmi+0x16/0x67
>> [ 4223.822639] RIP: 0010:qi_submit_sync+0x2c0/0x490
>> [ 4223.822639] Code: 48 be 00 00 00 00 00 08 00 00 49 85 74 24 20 0f
>> 95 c1 48 8b
>> 57 10 83 c1 04 83 3c 1a 03 0f 84 a2 01 00 00 49 8b 04 24 8b 70 34
>> <40> f6 c6 10
>> 74 17 49 8b 04 24 8b 80 80 00 00 00 89 c2 d3 fa 41 39
>> [ 4223.822640] RSP: 0018:ffffc4f074f0bbb8 EFLAGS: 00000093
>> [ 4223.822640] RAX: ffffc4f040059000 RBX: 0000000000000014 RCX:
>> 0000000000000005
>> [ 4223.822640] RDX: ffff9f3841315800 RSI: 0000000000000000 RDI:
>> ffff9f38401a8340
>> [ 4223.822641] RBP: ffff9f38401a8340 R08: ffffc4f074f0bc00 R09:
>> 0000000000000000
>> [ 4223.822641] R10: 0000000000000010 R11: 0000000000000018 R12:
>> ffff9f384005e200
>> [ 4223.822641] R13: 0000000000000004 R14: 0000000000000046 R15:
>> 0000000000000004
>> [ 4223.822641] ? qi_submit_sync+0x2c0/0x490
>> [ 4223.822642] ? qi_submit_sync+0x2c0/0x490
>> [ 4223.822642] </NMI>
>> [ 4223.822642] qi_flush_dev_iotlb+0xb1/0xd0
>> [ 4223.822642] __dmar_remove_one_dev_info+0x224/0x250
>> [ 4223.822643] dmar_remove_one_dev_info+0x3e/0x50
>> [ 4223.822643] intel_iommu_release_device+0x1f/0x30
>> [ 4223.822643] iommu_release_device+0x33/0x60
>> [ 4223.822643] iommu_bus_notifier+0x7f/0x90
>> [ 4223.822644] blocking_notifier_call_chain+0x60/0x90
>> [ 4223.822644] device_del+0x2e5/0x420
>> [ 4223.822644] pci_remove_bus_device+0x70/0x110
>> [ 4223.822644] pciehp_unconfigure_device+0x7c/0x130
>> [ 4223.822644] pciehp_disable_slot+0x6b/0x100
>> [ 4223.822645] pciehp_handle_presence_or_link_change+0xd8/0x320
>> [ 4223.822645] pciehp_ist+0x176/0x180
>> [ 4223.822645] ? irq_finalize_oneshot.part.50+0x110/0x110
>> [ 4223.822645] irq_thread_fn+0x19/0x50
>> [ 4223.822646] irq_thread+0x104/0x190
>> [ 4223.822646] ? irq_forced_thread_fn+0x90/0x90
>> [ 4223.822646] ? irq_thread_check_affinity+0xe0/0xe0
>> [ 4223.822646] kthread+0x114/0x130
>> [ 4223.822647] ? __kthread_cancel_work+0x40/0x40
>> [ 4223.822647] ret_from_fork+0x1f/0x30
>> [ 4223.822647] Kernel Offset: 0x6400000 from 0xffffffff81000000
>> (relocation
>> range: 0xffffffff80000000-0xffffffffbfffffff)
>>
>> Fix it by checking the device's error_state in
>> devtlb_invalidation_with_pasid() to avoid sending meaningless devTLB
>> flush
>> request to link down device that is set to
>> pci_channel_io_perm_failure and
>> then powered off in
>>
>> pciehp_ist()
>> pciehp_handle_presence_or_link_change()
>> pciehp_disable_slot()
>> remove_board()
>> pciehp_unconfigure_device()
>>
>> For SAFE_REMOVAL unplug, link is alive when iommu releases device and
>> issues devTLB invalidate request, wouldn't trigger such issue.
>>
>> This patch works for all kinds of SURPPRISE_REMOVAL unplug operation.
>>
>> Tested-by: Haorong Ye <yehaorong@...edance.com>
>> Signed-off-by: Ethan Zhao <haifeng.zhao@...ux.intel.com>
>> ---
>> drivers/iommu/intel/pasid.c | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
>> index 74e8e4c17e81..182eb5df244d 100644
>> --- a/drivers/iommu/intel/pasid.c
>> +++ b/drivers/iommu/intel/pasid.c
>> @@ -476,6 +476,23 @@ devtlb_invalidation_with_pasid(struct
>> intel_iommu *iommu,
>> {
>> struct device_domain_info *info;
>> u16 sid, qdep, pfsid;
>> + struct pci_dev *pdev;
>> +
>> + pdev = to_pci_dev(dev);
>> + if (!pdev)
>> + return;
>> +
>> + /*
>> + * If endpoint device's link was brough down by user's pci
>> configuration
>> + * access to it's hotplug capable slot link control register, as
>> sequence
>> + * response for DLLSC, pciehp_ist() will set the device
>> error_state to
>> + * pci_channel_io_perm_failure. Checking device's state here to
>> avoid
>> + * issuing meaningless devTLB flush request to it, that might
>> cause lockup
>> + * warning or deadlock because too long time waiting in
>> interrupt context.
>> + */
>> +
>> + if (pci_dev_is_disconnected(pdev))
>> + return;
>> info = dev_iommu_priv_get(dev);
>> if (!info || !info->ats_enabled)
>
> It's likely better to check the device status after verifying
> ats_enabled. How about below change?
>
> diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
> index 74e8e4c17e81..fa19c6cdfd8b 100644
> --- a/drivers/iommu/intel/pasid.c
> +++ b/drivers/iommu/intel/pasid.c
> @@ -481,6 +481,9 @@ devtlb_invalidation_with_pasid(struct intel_iommu
> *iommu,
> if (!info || !info->ats_enabled)
> return;
>
> + if (pci_dev_is_disconnected(to_pci_dev(dev)))
I like this kind of simplicity, but rationalist always brings me back to
the no-error(ugly)
style. :)
Thanks,
Ethan
> + return
> +
> sid = info->bus << 8 | info->devfn;
> qdep = info->ats_qdep;
> pfsid = info->pfsid;
>
> Best regards,
> baolu
>
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