3 ms·
This interests me, too. I can only assume, since disabling DMA would imply a huge performance hit (and quite likely many broken devices?), that the update enabl
by dom0 10y ago
This interests me, too. I can only assume, since disabling DMA would imply a huge performance hit (and quite likely many broken devices?), that the update enables the IOMMU right from the system start, probably directly in the firmware, and has nothing/only a whitelist mapped, with further mappings only explicitly enabled by drivers?
- astrodust 10y agoI 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.
- deleted 10y ago[deleted]