* [RFC PATCH v7 1/4] iommu/vt-d: add flush_target_dev member to struct intel_iommu and pass device info to all ATS invalidation functions
2023-12-25 8:25 [RFC PATCH v7 0/4] fix vt-d hard lockup when hotplug ATS capable device Ethan Zhao
@ 2023-12-25 8:25 ` Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 2/4] iommu/vt-d: break out device-TLB invalidation if target device is gone Ethan Zhao
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ethan Zhao @ 2023-12-25 8:25 UTC (permalink / raw)
To: bhelgaas, baolu.lu, dwmw2, will, robin.murphy, lukas
Cc: linux-pci, iommu, linux-kernel
As iommu is a pointer member of device_domain_info, so can't play
trick like container_of() to get the info and device instance for
qi_submit_sync() low level function to check device status, add a
flush_target_dev member to struct inte_iommu and pass dev info to
all device-TLB invalidation (a.k.a ATS invalidation) functions.
Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 1 +
drivers/iommu/intel/iommu.h | 2 ++
drivers/iommu/intel/pasid.c | 1 +
drivers/iommu/intel/svm.c | 1 +
4 files changed, 5 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 897159dba47d..c3724f1d86dc 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1461,6 +1461,7 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
sid = info->bus << 8 | info->devfn;
qdep = info->ats_qdep;
+ info->iommu->flush_target_dev = info->dev;
qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
qdep, addr, mask);
quirk_extra_dev_tlb_flush(info, addr, mask, IOMMU_NO_PASID, qdep);
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index ce030c5b5772..e892c5c7560a 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -731,6 +731,8 @@ struct intel_iommu {
void *perf_statistic;
struct iommu_pmu *pmu;
+
+ struct device *flush_target_dev; /* the target device TLB to be invalidated. */
};
/* PCI domain-device relationship */
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 74e8e4c17e81..1c87fb1b1039 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -485,6 +485,7 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu,
qdep = info->ats_qdep;
pfsid = info->pfsid;
+ info->iommu->flush_target_dev = info->dev;
/*
* When PASID 0 is used, it indicates RID2PASID(DMA request w/o PASID),
* devTLB flush w/o PASID should be used. For non-zero PASID under
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index ac12f76c1212..d42a99801cdf 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -181,6 +181,7 @@ static void __flush_svm_range_dev(struct intel_svm *svm,
qi_flush_piotlb(sdev->iommu, sdev->did, svm->pasid, address, pages, ih);
if (info->ats_enabled) {
+ info->iommu->flush_target_dev = info->dev;
qi_flush_dev_iotlb_pasid(sdev->iommu, sdev->sid, info->pfsid,
svm->pasid, sdev->qdep, address,
order_base_2(pages));
--
2.31.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [RFC PATCH v7 2/4] iommu/vt-d: break out device-TLB invalidation if target device is gone
2023-12-25 8:25 [RFC PATCH v7 0/4] fix vt-d hard lockup when hotplug ATS capable device Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 1/4] iommu/vt-d: add flush_target_dev member to struct intel_iommu and pass device info to all ATS invalidation functions Ethan Zhao
@ 2023-12-25 8:25 ` Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 3/4] PCI: make pci_dev_is_disconnected() helper public for other drivers Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 4/4] iommu/vt-d: don't issue device-TLB invalidate request when device is disconnected Ethan Zhao
3 siblings, 0 replies; 5+ messages in thread
From: Ethan Zhao @ 2023-12-25 8:25 UTC (permalink / raw)
To: bhelgaas, baolu.lu, dwmw2, will, robin.murphy, lukas
Cc: linux-pci, iommu, linux-kernel
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 pciehp_ist() DLLSC
interrupt sequence response, pciehp will unload the device driver and
then power it off. thus cause an IOMMU device-TLB invalidation (Intel
vt-d spec, or ATS invalidation in PCIe spec r6.1) 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)
Furthermore even an in-process safe removal unplugged device could be
surprise removed anytime, thus need to check the ATS invalidation target
device state to see if it is gone, and don't wait for the completion/
timeout blindly, thus avoid the up to 1min+50% (see Implementation Note
in PCIe spec r6.1 sec 10.3.1) waiting and cause hard lockup or system
hang.
Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
drivers/iommu/intel/dmar.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 23cb80d62a9a..76903a8bf963 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1347,6 +1347,7 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
unsigned int count, unsigned long options)
{
struct q_inval *qi = iommu->qi;
+ struct pci_dev *pdev = NULL;
s64 devtlb_start_ktime = 0;
s64 iotlb_start_ktime = 0;
s64 iec_start_ktime = 0;
@@ -1360,6 +1361,9 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
if (!qi)
return 0;
+ if (iommu->flush_target_dev && dev_is_pci(iommu->flush_target_dev))
+ pdev = to_pci_dev(iommu->flush_target_dev);
+
type = desc->qw0 & GENMASK_ULL(3, 0);
if ((type == QI_IOTLB_TYPE || type == QI_EIOTLB_TYPE) &&
@@ -1423,6 +1427,14 @@ int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
writel(qi->free_head << shift, iommu->reg + DMAR_IQT_REG);
while (qi->desc_status[wait_index] != QI_DONE) {
+ /*
+ * if the device-TLB invalidation target device is gone, don't
+ * wait anymore, it might take up to 1min+50%, causes system
+ * hang. (see Implementation Note in PCIe spec r6.1 sec 10.3.1)
+ */
+ if ((type == QI_DIOTLB_TYPE || type == QI_DEIOTLB_TYPE) && pdev)
+ if (!pci_device_is_present(pdev))
+ break;
/*
* We will leave the interrupts disabled, to prevent interrupt
* context to queue another cmd while a cmd is already submitted
--
2.31.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [RFC PATCH v7 3/4] PCI: make pci_dev_is_disconnected() helper public for other drivers
2023-12-25 8:25 [RFC PATCH v7 0/4] fix vt-d hard lockup when hotplug ATS capable device Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 1/4] iommu/vt-d: add flush_target_dev member to struct intel_iommu and pass device info to all ATS invalidation functions Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 2/4] iommu/vt-d: break out device-TLB invalidation if target device is gone Ethan Zhao
@ 2023-12-25 8:25 ` Ethan Zhao
2023-12-25 8:25 ` [RFC PATCH v7 4/4] iommu/vt-d: don't issue device-TLB invalidate request when device is disconnected Ethan Zhao
3 siblings, 0 replies; 5+ messages in thread
From: Ethan Zhao @ 2023-12-25 8:25 UTC (permalink / raw)
To: bhelgaas, baolu.lu, dwmw2, will, robin.murphy, lukas
Cc: linux-pci, iommu, linux-kernel
Make pci_dev_is_disconnected() public so that it can be called from
Intel vt-d driver to quickly fix/workaround the surprise removal
unplug hang issue for those ATS capable devices on PCIe switch downstream
hotplug capable ports.
Beside pci_device_is_present() function, this one has no config space
space access, so is light enough to optimize the normal pure surprise
removal and safe removal flow.
Tested-by: Haorong Ye <yehaorong@bytedance.com>
Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
drivers/pci/pci.h | 5 -----
include/linux/pci.h | 5 +++++
2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 5ecbcf041179..75fa2084492f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -366,11 +366,6 @@ static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused)
return 0;
}
-static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
-{
- return dev->error_state == pci_channel_io_perm_failure;
-}
-
/* pci_dev priv_flags */
#define PCI_DEV_ADDED 0
#define PCI_DPC_RECOVERED 1
diff --git a/include/linux/pci.h b/include/linux/pci.h
index dea043bc1e38..4779eec8b267 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -2506,6 +2506,11 @@ static inline struct pci_dev *pcie_find_root_port(struct pci_dev *dev)
return NULL;
}
+static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
+{
+ return dev->error_state == pci_channel_io_perm_failure;
+}
+
void pci_request_acs(void);
bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags);
bool pci_acs_path_enabled(struct pci_dev *start,
--
2.31.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [RFC PATCH v7 4/4] iommu/vt-d: don't issue device-TLB invalidate request when device is disconnected
2023-12-25 8:25 [RFC PATCH v7 0/4] fix vt-d hard lockup when hotplug ATS capable device Ethan Zhao
` (2 preceding siblings ...)
2023-12-25 8:25 ` [RFC PATCH v7 3/4] PCI: make pci_dev_is_disconnected() helper public for other drivers Ethan Zhao
@ 2023-12-25 8:25 ` Ethan Zhao
3 siblings, 0 replies; 5+ messages in thread
From: Ethan Zhao @ 2023-12-25 8:25 UTC (permalink / raw)
To: bhelgaas, baolu.lu, dwmw2, will, robin.murphy, lukas
Cc: linux-pci, iommu, linux-kernel
Except those aggressive hotplug cases - surpise remove a hotplug device
while its safe removal is requested and handled in process by:
1. pull it out directly.
2. turn off its power.
3. bring the link down.
4. just died there that moment.
etc, in a word, 'gone' or 'disconnected'.
Mostly are regular normal safe removal and surprise removal unplug.
these hot unplug handling process could be optimized for fix the ATS
invalidation hang issue by calling pci_dev_is_disconnected() in function
devtlb_invalidation_with_pasid() to check target device state to avoid
sending meaningless ATS invalidation request to iommu when device is gone.
(see IMPLEMENTATION NOTE in PCIe spec r6.1 section 10.3.1)
For safe removal, device wouldn't be removed until the whole software
handling process is done, it wouldn't trigger the hard lock up issue
caused by too long ATS invalidation timeout wait. in safe removal path,
device state isn't set to pci_channel_io_perm_failure in
pciehp_unconfigure_device() by checking 'presence' parameter, calling
pci_dev_is_disconnected() in devtlb_invalidation_with_pasid() will return
false there, wouldn't break the function.
For surprise removal, device state is set to pci_channel_io_perm_failure in
pciehp_unconfigure_device(), means device is already gone (disconnected)
call pci_dev_is_disconnected() in devtlb_invalidation_with_pasid() will
return true to break the function not to send ATS invalidation request to
the disconnected device blindly, thus avoid the further long time waiting
triggers the hard lockup.
safe removal & surprise removal
pciehp_ist()
pciehp_handle_presence_or_link_change()
pciehp_disable_slot()
remove_board()
pciehp_unconfigure_device(presence)
Tested-by: Haorong Ye <yehaorong@bytedance.com>
Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com>
---
drivers/iommu/intel/pasid.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 1c87fb1b1039..a08bdbec90eb 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)))
+ return;
+
sid = info->bus << 8 | info->devfn;
qdep = info->ats_qdep;
pfsid = info->pfsid;
--
2.31.1
^ permalink raw reply related [flat|nested] 5+ messages in thread