On Fri, Feb 23, 2024 at 10:29:28AM +0800, Ethan Zhao wrote:
Reading this comment again, the part about zero ite_sid values isReally confusing ? this is typo there, resnet-> "present"@@ -1326,6 +1336,21 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index)This comment is kind of confusing.
head = (head - 2 + QI_LENGTH) % QI_LENGTH;
} while (head != tail);
+ /*
+ * If got ITE, we need to check if the sid of ITE is one of the
+ * current valid ATS invalidation target devices, if no, or the
+ * target device isn't presnet, don't try this request anymore.
+ * 0 value of ite_sid means old VT-d device, no ite_sid value.
+ */
actually useful, but what does "old" mean in "old VT-d device". How old
is it? One year old?
I don't really care about the return value and if you say it should be/*-ETIMEDOUT means prior ATS invalidation request hit timeout fault, and the
* If we have an ITE, then we need to check whether the sid of the ITE
* is in the rbtree (meaning it is probed and not released), and that
* the PCI device is present.
*/
My comment is slightly shorter but I think it has the necessary
information.
+ if (ite_sid) {-ETIMEDOUT is weird. The callers don't care which error code we return.
+ dev = device_rbtree_find(iommu, ite_sid);
+ if (!dev || !dev_is_pci(dev))
+ return -ETIMEDOUT;
Change this to -ENODEV or something
caller really cares about the returned value.
-ETIMEDOUT, then you're the expert. However, I don't see anything in
linux-next which cares about the return values except -EAGAIN.
This function is only called from qi_submit_sync() which checks for
-EAGAIN. Then I did a git grep.
$ git grep qi_submit_sync
drivers/iommu/intel/dmar.c:int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/dmar.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/iommu.h:int qi_submit_sync(struct intel_iommu *iommu, struct qi_desc *desc,
drivers/iommu/intel/iommu.h: * Options used in qi_submit_sync:
drivers/iommu/intel/irq_remapping.c: return qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/pasid.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/svm.c: qi_submit_sync(iommu, desc, 3, QI_OPT_WAIT_DRAIN);
drivers/iommu/intel/svm.c: qi_submit_sync(iommu, &desc, 1, 0);
drivers/iommu/intel/svm.c: qi_submit_sync(iommu, &desc, 1, 0);
Only qi_flush_iec() in irq_remapping.c cares about the return. Then I
traced those callers back and nothing cares about -ETIMEOUT.
Are you refering to patches that haven't ben merged yet?
Basically for that to ever be != it would need some kind of memoryHere is the fault handling, just double confirm nothing else goes wrong --+ pdev = to_pci_dev(dev);The && confused me, but then I realized that probably "ite_sid ==
+ if (!pci_device_is_present(pdev) &&
+ ite_sid == pci_dev_id(pci_physfn(pdev)))
pci_dev_id(pci_physfn(pdev))" is always true. Can we delete that part?
beyond the assumption.
corruption? I feel like in that situation, the more conservative thing
is to give up. If the PCI device is not present then just give up.
regards,
dan carpenter