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Diffstat (limited to 'Documentation/fpga/dfl.rst')
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diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst index 2f125abd777f..6fa483fc823e 100644 --- a/Documentation/fpga/dfl.rst +++ b/Documentation/fpga/dfl.rst @@ -87,6 +87,8 @@ The following functions are exposed through ioctls: - Get driver API version (DFL_FPGA_GET_API_VERSION) - Check for extensions (DFL_FPGA_CHECK_EXTENSION) - Program bitstream (DFL_FPGA_FME_PORT_PR) +- Assign port to PF (DFL_FPGA_FME_PORT_ASSIGN) +- Release port from PF (DFL_FPGA_FME_PORT_RELEASE) More functions are exposed through sysfs (/sys/class/fpga_region/regionX/dfl-fme.n/): @@ -102,6 +104,10 @@ More functions are exposed through sysfs one FPGA device may have more than one port, this sysfs interface indicates how many ports the FPGA device has. + Global error reporting management (errors/) + error reporting sysfs interfaces allow user to read errors detected by the + hardware, and clear the logged errors. + FIU - PORT ========== @@ -143,6 +149,10 @@ More functions are exposed through sysfs: Read Accelerator GUID (afu_id) afu_id indicates which PR bitstream is programmed to this AFU. + Error reporting (errors/) + error reporting sysfs interfaces allow user to read port/afu errors + detected by the hardware, and clear the logged errors. + DFL Framework Overview ====================== @@ -218,6 +228,101 @@ the compat_id exposed by the target FPGA region. This check is usually done by userspace before calling the reconfiguration IOCTL. +FPGA virtualization - PCIe SRIOV +================================ +This section describes the virtualization support on DFL based FPGA device to +enable accessing an accelerator from applications running in a virtual machine +(VM). This section only describes the PCIe based FPGA device with SRIOV support. + +Features supported by the particular FPGA device are exposed through Device +Feature Lists, as illustrated below: + +:: + + +-------------------------------+ +-------------+ + | PF | | VF | + +-------------------------------+ +-------------+ + ^ ^ ^ ^ + | | | | + +-----|------------|---------|--------------|-------+ + | | | | | | + | +-----+ +-------+ +-------+ +-------+ | + | | FME | | Port0 | | Port1 | | Port2 | | + | +-----+ +-------+ +-------+ +-------+ | + | ^ ^ ^ | + | | | | | + | +-------+ +------+ +-------+ | + | | AFU | | AFU | | AFU | | + | +-------+ +------+ +-------+ | + | | + | DFL based FPGA PCIe Device | + +---------------------------------------------------+ + +FME is always accessed through the physical function (PF). + +Ports (and related AFUs) are accessed via PF by default, but could be exposed +through virtual function (VF) devices via PCIe SRIOV. Each VF only contains +1 Port and 1 AFU for isolation. Users could assign individual VFs (accelerators) +created via PCIe SRIOV interface, to virtual machines. + +The driver organization in virtualization case is illustrated below: +:: + + +-------++------++------+ | + | FME || FME || FME | | + | FPGA || FPGA || FPGA | | + |Manager||Bridge||Region| | + +-------++------++------+ | + +-----------------------+ +--------+ | +--------+ + | FME | | AFU | | | AFU | + | Module | | Module | | | Module | + +-----------------------+ +--------+ | +--------+ + +-----------------------+ | +-----------------------+ + | FPGA Container Device | | | FPGA Container Device | + | (FPGA Base Region) | | | (FPGA Base Region) | + +-----------------------+ | +-----------------------+ + +------------------+ | +------------------+ + | FPGA PCIE Module | | Virtual | FPGA PCIE Module | + +------------------+ Host | Machine +------------------+ + -------------------------------------- | ------------------------------ + +---------------+ | +---------------+ + | PCI PF Device | | | PCI VF Device | + +---------------+ | +---------------+ + +FPGA PCIe device driver is always loaded first once a FPGA PCIe PF or VF device +is detected. It: + +* Finishes enumeration on both FPGA PCIe PF and VF device using common + interfaces from DFL framework. +* Supports SRIOV. + +The FME device driver plays a management role in this driver architecture, it +provides ioctls to release Port from PF and assign Port to PF. After release +a port from PF, then it's safe to expose this port through a VF via PCIe SRIOV +sysfs interface. + +To enable accessing an accelerator from applications running in a VM, the +respective AFU's port needs to be assigned to a VF using the following steps: + +#. The PF owns all AFU ports by default. Any port that needs to be + reassigned to a VF must first be released through the + DFL_FPGA_FME_PORT_RELEASE ioctl on the FME device. + +#. Once N ports are released from PF, then user can use command below + to enable SRIOV and VFs. Each VF owns only one Port with AFU. + + :: + + echo N > $PCI_DEVICE_PATH/sriov_numvfs + +#. Pass through the VFs to VMs + +#. The AFU under VF is accessible from applications in VM (using the + same driver inside the VF). + +Note that an FME can't be assigned to a VF, thus PR and other management +functions are only available via the PF. + Device enumeration ================== This section introduces how applications enumerate the fpga device from |