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Diffstat (limited to 'Documentation/mic/mic_overview.txt')
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diff --git a/Documentation/mic/mic_overview.txt b/Documentation/mic/mic_overview.txt deleted file mode 100644 index 074adbdf83a4..000000000000 --- a/Documentation/mic/mic_overview.txt +++ /dev/null @@ -1,81 +0,0 @@ -An Intel MIC X100 device is a PCIe form factor add-in coprocessor -card based on the Intel Many Integrated Core (MIC) architecture -that runs a Linux OS. It is a PCIe endpoint in a platform and therefore -implements the three required standard address spaces i.e. configuration, -memory and I/O. The host OS loads a device driver as is typical for -PCIe devices. The card itself runs a bootstrap after reset that -transfers control to the card OS downloaded from the host driver. The -host driver supports OSPM suspend and resume operations. It shuts down -the card during suspend and reboots the card OS during resume. -The card OS as shipped by Intel is a Linux kernel with modifications -for the X100 devices. - -Since it is a PCIe card, it does not have the ability to host hardware -devices for networking, storage and console. We provide these devices -on X100 coprocessors thus enabling a self-bootable equivalent -environment for applications. A key benefit of our solution is that it -leverages the standard virtio framework for network, disk and console -devices, though in our case the virtio framework is used across a PCIe -bus. A Virtio Over PCIe (VOP) driver allows creating user space -backends or devices on the host which are used to probe virtio drivers -for these devices on the MIC card. The existing VRINGH infrastructure -in the kernel is used to access virtio rings from the host. The card -VOP driver allows card virtio drivers to communicate with their user -space backends on the host via a device page. Ring 3 apps on the host -can add, remove and configure virtio devices. A thin MIC specific -virtio_config_ops is implemented which is borrowed heavily from -previous similar implementations in lguest and s390. - -MIC PCIe card has a dma controller with 8 channels. These channels are -shared between the host s/w and the card s/w. 0 to 3 are used by host -and 4 to 7 by card. As the dma device doesn't show up as PCIe device, -a virtual bus called mic bus is created and virtual dma devices are -created on it by the host/card drivers. On host the channels are private -and used only by the host driver to transfer data for the virtio devices. - -The Symmetric Communication Interface (SCIF (pronounced as skiff)) is a -low level communications API across PCIe currently implemented for MIC. -More details are available at scif_overview.txt. - -The Coprocessor State Management (COSM) driver on the host allows for -boot, shutdown and reset of Intel MIC devices. It communicates with a COSM -"client" driver on the MIC cards over SCIF to perform these functions. - -Here is a block diagram of the various components described above. The -virtio backends are situated on the host rather than the card given better -single threaded performance for the host compared to MIC, the ability of -the host to initiate DMA's to/from the card using the MIC DMA engine and -the fact that the virtio block storage backend can only be on the host. - - +----------+ | +----------+ - | Card OS | | | Host OS | - +----------+ | +----------+ - | - +-------+ +--------+ +------+ | +---------+ +--------+ +--------+ - | Virtio| |Virtio | |Virtio| | |Virtio | |Virtio | |Virtio | - | Net | |Console | |Block | | |Net | |Console | |Block | - | Driver| |Driver | |Driver| | |backend | |backend | |backend | - +---+---+ +---+----+ +--+---+ | +---------+ +----+---+ +--------+ - | | | | | | | - | | | |User | | | - | | | |------|------------|--+------|------- - +---------+---------+ |Kernel | - | | | - +---------+ +---+----+ +------+ | +------+ +------+ +--+---+ +-------+ - |MIC DMA | | VOP | | SCIF | | | SCIF | | COSM | | VOP | |MIC DMA| - +---+-----+ +---+----+ +--+---+ | +--+---+ +--+---+ +------+ +----+--+ - | | | | | | | - +---+-----+ +---+----+ +--+---+ | +--+---+ +--+---+ +------+ +----+--+ - |MIC | | VOP | |SCIF | | |SCIF | | COSM | | VOP | | MIC | - |HW Bus | | HW Bus| |HW Bus| | |HW Bus| | Bus | |HW Bus| |HW Bus | - +---------+ +--------+ +--+---+ | +--+---+ +------+ +------+ +-------+ - | | | | | | | - | +-----------+--+ | | | +---------------+ | - | |Intel MIC | | | | |Intel MIC | | - | |Card Driver | | | | |Host Driver | | - +---+--------------+------+ | +----+---------------+-----+ - | | | - +-------------------------------------------------------------+ - | | - | PCIe Bus | - +-------------------------------------------------------------+ |