[PATCH 2/2] iommu/vt-d: don's issue devTLB flush request when device is disconnected

Ethan Zhao
2023-12-13T03:47:47Z

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
as following

[ 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()

Tested-by: Haorong Ye <yehaorong@bytedance.com>
Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
drivers/iommu/intel/pasid.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 74e8e4c17e81..8557b6dee22f 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's 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)
@@ -495,6 +512,8 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 - VTD_PAGE_SHIFT);
else
qi_flush_dev_iotlb_pasid(iommu, sid, pfsid, pasid, qdep, 0, 64 - VTD_PAGE_SHIFT);
+
+ return;
}

void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device *dev,
--
2.31.1