Hi, Generally speaking, PCI devices use IOMMU (for x86) or SMMU (for ARM) for virtual to physical address translation. In the current version of gem5, I noticed that there is indeed an SMMU for the ARM architecture, but I couldn't find a similar component for x86. I have examined the DMA process for typical PCI devices such as copy_engine and ide under x86, but I don't understand how they perform the virtual to physical address translation. I would like to ask for your help in understanding how PCI devices under x86 perform virtual to physical address translation. Or, can I use the SMMU in an x86 system? I am mainly focusing on full system simulations. Thank you! Best Regards, Wang