3 ms·
I wonder if the chipset can't do a sort of DMA emulation, or DMA with conditions versus the sort of free-for-all stuff you'd see with things like FireWire.
by astrodust 10y ago
I wonder if the chipset can't do a sort of DMA emulation, or DMA with conditions versus the sort of free-for-all stuff you'd see with things like FireWire.
- dom0 10y agoThat's what an IOMMU does. Without an IOMMU devices on extension buses directly address physical memory. With an MMU the host CPU creates a virtual address space for devices and can thus limit access to the main memory (conveniently also allows passing devices to VM guests), much like virtual memory for processes/VMs.