AC82G41SLGQ3 Datasheet, PDF (544/604 Pages) Intel Corporation – Intel® 4 Series Chipset Family

Functional Description
13.6.2.1
Intel Virtualization Technology for I/O Devices Enables
• Multiple containers (silos) or domains run on a single hardware platform, fully
isolated from each other. Dedicated hardware can be assigned to each container.
Address space remap prevents hardware from accessing space outside its memory
allocation.
• Flexible memory management by VMM.
• Un-modified device drivers to run in both partitions.
• Contain DMA errors across partitions.
• Allows enforcement of independent security policies for each partition.
13.6.2.2
13.6.2.3
Hardware Versus Software Virtualization
• Though software-only approach for I/O device management provides a few
advantages like easier VM mobility across physical machines, this approach has
some serious limitations.
Hardware Virtualization Advantages
• Hardware or device virtualization doesn’t cause any changes to guest OS.
• No hardware functionality lost in virtual driver interface.
• VMM can be small since minimal drivers needed, thereby avoiding significant
processor utilization overhead, and hence increases system performance.
• Hardware approach provides more robust memory protection as described earlier.
13.6.3
Concept of DMA Address Remapping
This section describes the hardware architecture concepts of DMA remapping.
The DMA-remapping architecture facilitates flexible assignment of I/O devices to an
arbitrary number of domains. Each domain has a view of physical address space that
may be different than the host physical address space. DMA-remapping treats the
address specified in DMA requests as DMA virtual addresses (DVA). Depending on the
software usage model, the DMA virtual address space may be the same as the guest-
physical address (GPA) space of the domain to which the I/O device is assigned, or a
purely virtual address space defined by software. In either case, DMA-remapping
provides the transformation of address in a DMA request issued by an I/O device to its
corresponding host-physical address (HPA).
For simplicity, the rest of the document describes the input address to the DMA-
remapping hardware as GPA. Figure 16 illustrates the I/O physical address translation.
I/O devices 1 and 2 are assigned to domains 1 and 2 respectively. The software
responsible for creating and managing the domains allocates system physical memory
for both domains and sets up the DMA address translation function. GPA in DMA
requests initiated by devices 1 and 2 are translated to appropriate HPAs by the DMA
remapping hardware.
544
Datasheet