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Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > Hi Suravee, > >> A translate device ID (TransDevID) is a host device-table index used >> by hardware vIOMMU. VFCTRL guest-misc names the slot; that DTE holds >> the nest-parent v1 table for GPA->SPA walks of guest IOMMU traffic. > >> Reserve PCI requestor IDs in a per-segment pool so they are not >> used as vIOMMU translation DTEs. The device table is per-segment, >> so the pool is too. >> >> Add trans_devid.c with pci_seg init/fini and >> amd_iommu_trans_devid_reserve() from probe_device(). Keep >> reservations for the pci_seg lifetime, including after >> amd_iommu_release_device(). > > Reservation only happens on the probe path, but some DTE-slot holders > never probe, so their devids stay unreserved while > trans_devid_find_free_locked() [patch 22] treats any xa_load()==NULL > slot as free. > > One such holder is the IOMMU's own function: init.c deliberately does > rlookup_table[iommu->devid] = NULL , so it never reaches probe_device() > -- yet patch 13 programs the self DTE at exactly iommu->devid. > > Thanks, > fuwenxin Good catch. I'll update v6 to also reserve PCI BDF of the IOMMUs (i.e. iommu->devid) Thanks, Suravee