On 2022-01-30 07:43, Joerg Roedel wrote:
Hi Jacob, Baolu,
On Fri, Jan 28, 2022 at 11:10:01AM +0800, Lu Baolu wrote:
During PCI bus rescan, adding new devices involve two notifiers.
1. dmar_pci_bus_notifier()
2. iommu_bus_notifier()
The current code sets #1 as low priority (INT_MIN) which resulted in #2
being invoked first. The result is that struct device pointer cannot be
found in DRHD search for the new device's DMAR/IOMMU. Subsequently, the
device is put under the "catch-all" IOMMU instead of the correct one.
There are actually iommu_ops pointers invoked from iommu_bus_notifier()
into IOMMU driver code. Can those be used to enforce the ordering in a
more reliable way?
Indeed I very nearly asked whether we couldn't just call these from
intel_iommu_{probe,release}_device() directly, but it looks like they
also interact with the interrupt remapping stuff which can be built
independently of the IOMMU API :(
Robin.
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