Hi David, > -----Original Message----- > From: David Marchand <[email protected]> > Sent: Friday, January 15, 2021 3:58 PM > To: Xia, Chenbo <[email protected]> > Cc: dev <[email protected]>; Thomas Monjalon <[email protected]>; Stephen > Hemminger <[email protected]>; Liang, Cunming > <[email protected]>; Lu, Xiuchun <[email protected]>; Li, Miao > <[email protected]>; Wu, Jingjing <[email protected]>; Xing, Beilei > <[email protected]> > Subject: Re: [PATCH v2 0/9] Introduce vfio-user library > > Hello Chenbo, > > On Thu, Jan 14, 2021 at 7:19 AM Chenbo Xia <[email protected]> wrote: > > > > This series enables DPDK to be an alternative I/O device emulation library > of > > building virtualized devices in separate processes outside QEMU. It > introduces > > a new library for device emulation (librte_vfio_user). > > > > *librte_vfio_user* library is an implementation of VFIO-over-socket[1] (also > > known as vfio-user) which is a protocol that allows a device to be > virtualized > > in a separate process outside of QEMU. > > > > Background & Motivation > > ----------------------- > > The disaggregated/multi-process QEMU is using VFIO-over-socket/vfio-user > > as the main transport mechanism to disaggregate IO services from QEMU[2]. > > Vfio-user essentially implements the VFIO device model presented to the > > user process by a set of messages over a unix-domain socket. The main > > difference between application using vfio-user and application using vfio > > kernel module is that device manipulation is based on socket messages for > > vfio-user but system calls for vfio kernel module. The vfio-user devices > > consist of a generic VFIO device type, living in QEMU, which is called the > > client[3], and the core device implementation (emulated device), living > > outside of QEMU, which is called the server. With emulated devices removed > > from QEMU enabled by vfio-user implementation, other places should be > > introduced to accommodate virtualized/emulated device. This series > introduces > > vfio-user support in DPDK to enable DPDK as one of the living places for > > emulated device except QEMU. > > > > This series introduce the server and client implementation of vfio-user > protocol. > > The server plays the role as emulated devices and the client is the device > > consumer. With this implementation, DPDK will be enabled to be both device > > provider and consumer. > > > > Design overview > > --------------- > > > > +--------------+ +--------------+ > > | +----------+ | | +----------+ | > > | | Generic | | | | Emulated | | > > | | vfio-dev | | | | device | | > > | +----------+ | | +----|-----+ | > > | +----------+ | | +----|-----+ | > > | | vfio-user| | | | vfio-user| | > > | | client | |<--->| | server | | > > | +----------+ | | +----------+ | > > | QEMU/DPDK | | DPDK | > > +--------------+ +--------------+ > > > > - Generic vfio-dev. > > It is the generic vfio framework in vfio applications like QEMU or DPDK. > > Applications can keep the most of vfio device management and plug in a > > vfio-user device type. Note that in current implementation, we have not > > yet integrated client vfio-user into kernel vfio in DPDK but it is viable > > and good to do so. > > > > - vfio-user client. > > For DPDK, it is part of librte_vfio_user implementation to provide ways to > > manipulate a vfio-user based emulated devices. This manipulation is very > > similar with kernel vfio (i.e., syscalls like ioctl, mmap and > pread/pwrite). > > It is a base for vfio-user device consumer. > > > > - vfio-user server. > > It is server part of librte_vfio_user. It provides ways to emulate your > own > > device. A device provider could only care about device layout that VFIO > > defines but does not need to know how it communicates with vfio-user > client. > > > > - Emulated device. > > It is emulated device of any type (e.g., network, crypto and etc.). > > > > References > > ---------- > > [1]: https://patchew.org/QEMU/20201130161229.23164-1- > [email protected]/ > > [2]: https://wiki.qemu.org/Features/MultiProcessQEMU > > [3]: https://github.com/oracle/qemu/tree/vfio-user-v0.2 > > > > ---------------------------------- > > v2: > > - Clean up non-static inline function (Stephen) > > - Naturally pack vfio-user message payload and header (Stephen) > > - Make function definiton align with coding style (Beilei) > > - Clean up duplicate code in vfio-user server APIs (Beilei) > > - Fix some typos > > > GHA (called by the robot) caught various issues: > - doc: > https://github.com/ovsrobot/dpdk/runs/1700373705?check_suite_focus=true#step:1 > 4:3407 > - clang: > https://github.com/ovsrobot/dpdk/runs/1700373722?check_suite_focus=true#step:1 > 4:1050 > - i386: > https://github.com/ovsrobot/dpdk/runs/1700373747?check_suite_focus=true#step:1 > 4:2607 > - aarch64: > https://github.com/ovsrobot/dpdk/runs/1700373764?check_suite_focus=true#step:1 > 4:2848 > and > https://github.com/ovsrobot/dpdk/runs/1700373770?check_suite_focus=true#step:1 > 4:2880
Thanks! Will fix in next version. Chenbo > > > -- > David Marchand
