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Caz Yokoyama8d497512013-09-05 16:42:39 -07001An Intel MIC X100 device is a PCIe form factor add-in coprocessor
2card based on the Intel Many Integrated Core (MIC) architecture
3that runs a Linux OS. It is a PCIe endpoint in a platform and therefore
4implements the three required standard address spaces i.e. configuration,
5memory and I/O. The host OS loads a device driver as is typical for
6PCIe devices. The card itself runs a bootstrap after reset that
Dasaratharaman Chandramouliaf190492013-10-03 18:06:23 -07007transfers control to the card OS downloaded from the host driver. The
8host driver supports OSPM suspend and resume operations. It shuts down
9the card during suspend and reboots the card OS during resume.
Caz Yokoyama8d497512013-09-05 16:42:39 -070010The card OS as shipped by Intel is a Linux kernel with modifications
11for the X100 devices.
12
13Since it is a PCIe card, it does not have the ability to host hardware
14devices for networking, storage and console. We provide these devices
15on X100 coprocessors thus enabling a self-bootable equivalent environment
16for applications. A key benefit of our solution is that it leverages
17the standard virtio framework for network, disk and console devices,
18though in our case the virtio framework is used across a PCIe bus.
19
20Here is a block diagram of the various components described above. The
21virtio backends are situated on the host rather than the card given better
22single threaded performance for the host compared to MIC, the ability of
23the host to initiate DMA's to/from the card using the MIC DMA engine and
24the fact that the virtio block storage backend can only be on the host.
25
26 |
27 +----------+ | +----------+
28 | Card OS | | | Host OS |
29 +----------+ | +----------+
30 |
31+-------+ +--------+ +------+ | +---------+ +--------+ +--------+
32| Virtio| |Virtio | |Virtio| | |Virtio | |Virtio | |Virtio |
33| Net | |Console | |Block | | |Net | |Console | |Block |
34| Driver| |Driver | |Driver| | |backend | |backend | |backend |
35+-------+ +--------+ +------+ | +---------+ +--------+ +--------+
36 | | | | | | |
37 | | | |User | | |
38 | | | |------|------------|---------|-------
39 +-------------------+ |Kernel +--------------------------+
40 | | | Virtio over PCIe IOCTLs |
41 | | +--------------------------+
42 +--------------+ | |
43 |Intel MIC | | +---------------+
44 |Card Driver | | |Intel MIC |
45 +--------------+ | |Host Driver |
46 | | +---------------+
47 | | |
48 +-------------------------------------------------------------+
49 | |
50 | PCIe Bus |
51 +-------------------------------------------------------------+