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This allows RDMA and other subsystems to import > > dma-buf FDs and build them into memory regions for PCI P2P operations. > > > > The implementation provides a revocable attachment mechanism using > > dma-buf move operations. MMIO regions are normally pinned as BARs > > don't change physical addresses, but access is revoked when the VFIO > > device is closed or a PCI reset is issued. This ensures kernel > > self-defense against potentially hostile userspace. > > This still completely fails to explain why you think that it actually > is safe without the proper pgmap handling. Leon, this keeps coming up, please clean up and copy the text from my prior email into the commit message & cover letter explaining in detail how lifetime magement works by using revocation/invalidation driven by dmabuf move_notify callbacks. Jason