Messages in this thread | | | Date | Wed, 10 Jan 2024 16:40:02 +0800 | Subject | Re: [RFC PATCH v10 5/5] iommu/vt-d: don't loop for timeout ATS Invalidation request forever | From | Ethan Zhao <> |
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On 1/10/2024 1:28 PM, Baolu Lu wrote: > On 12/29/23 1:05 AM, Ethan Zhao wrote: >> When the ATS Invalidation request timeout happens, the qi_submit_sync() >> will restart and loop for the invalidation request forever till it is >> done, it will block another Invalidation thread such as the fq_timer >> to issue invalidation request, cause the system lockup as following >> >> [exception RIP: native_queued_spin_lock_slowpath+92] >> >> RIP: ffffffffa9d1025c RSP: ffffb202f268cdc8 RFLAGS: 00000002 >> >> RAX: 0000000000000101 RBX: ffffffffab36c2a0 RCX: 0000000000000000 >> >> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffab36c2a0 >> >> RBP: ffffffffab36c2a0 R8: 0000000000000001 R9: 0000000000000000 >> >> R10: 0000000000000010 R11: 0000000000000018 R12: 0000000000000000 >> >> R13: 0000000000000004 R14: ffff9e10d71b1c88 R15: ffff9e10d71b1980 >> >> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 >> >> (the left part of exception see the hotplug case of ATS capable device) >> >> If one endpoint device just no response to the ATS Invalidation request, >> but is not gone, it will bring down the whole system, to avoid such >> case, don't try the timeout ATS Invalidation request forever. >> >> Signed-off-by: Ethan Zhao <haifeng.zhao@linux.intel.com> >> --- >> drivers/iommu/intel/dmar.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c >> index 0a8d628a42ee..9edb4b44afca 100644 >> --- a/drivers/iommu/intel/dmar.c >> +++ b/drivers/iommu/intel/dmar.c >> @@ -1453,7 +1453,7 @@ int qi_submit_sync(struct intel_iommu *iommu, >> struct qi_desc *desc, >> reclaim_free_desc(qi); >> raw_spin_unlock_irqrestore(&qi->q_lock, flags); >> - if (rc == -EAGAIN) >> + if (rc == -EAGAIN && type !=QI_DIOTLB_TYPE && type != >> QI_DEIOTLB_TYPE) >> goto restart; >> if (iotlb_start_ktime) > > Above is also unnecessary if qi_check_fault() returns -ETIMEDOUT, > instead of -EAGAIN. Or did I miss anything?
It is pro if we fold it into qi_check_fault(), the con is we have to add
more parameter to qi_check_fault(), no need check invalidation type
of QI_DIOTLB_TYPE&QI_DEIOTLB_TYPE in qi_check_fault() ?
Thanks,
Ethan
> > Best regards, > baolu
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