639090d850
Adds documentation explaining the command-line arguments needed to use multi-process. Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com> Signed-off-by: John G Johnson <john.g.johnson@oracle.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 49f757a84e5dd6fae14b22544897d1124c5fdbad.1611938319.git.jag.raman@oracle.com [Move orphan docs/multi-process.rst document into docs/system/ and add it to index.rst to prevent Sphinx "document isn't included in any toctree" error. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
65 lines
2.0 KiB
ReStructuredText
65 lines
2.0 KiB
ReStructuredText
Multi-process QEMU
|
|
==================
|
|
|
|
This document describes how to configure and use multi-process qemu.
|
|
For the design document refer to docs/devel/qemu-multiprocess.
|
|
|
|
1) Configuration
|
|
----------------
|
|
|
|
multi-process is enabled by default for targets that enable KVM
|
|
|
|
|
|
2) Usage
|
|
--------
|
|
|
|
Multi-process QEMU requires an orchestrator to launch.
|
|
|
|
Following is a description of command-line used to launch mpqemu.
|
|
|
|
* Orchestrator:
|
|
|
|
- The Orchestrator creates a unix socketpair
|
|
|
|
- It launches the remote process and passes one of the
|
|
sockets to it via command-line.
|
|
|
|
- It then launches QEMU and specifies the other socket as an option
|
|
to the Proxy device object
|
|
|
|
* Remote Process:
|
|
|
|
- QEMU can enter remote process mode by using the "remote" machine
|
|
option.
|
|
|
|
- The orchestrator creates a "remote-object" with details about
|
|
the device and the file descriptor for the device
|
|
|
|
- The remaining options are no different from how one launches QEMU with
|
|
devices.
|
|
|
|
- Example command-line for the remote process is as follows:
|
|
|
|
/usr/bin/qemu-system-x86_64 \
|
|
-machine x-remote \
|
|
-device lsi53c895a,id=lsi0 \
|
|
-drive id=drive_image2,file=/build/ol7-nvme-test-1.qcow2 \
|
|
-device scsi-hd,id=drive2,drive=drive_image2,bus=lsi0.0,scsi-id=0 \
|
|
-object x-remote-object,id=robj1,devid=lsi1,fd=4,
|
|
|
|
* QEMU:
|
|
|
|
- Since parts of the RAM are shared between QEMU & remote process, a
|
|
memory-backend-memfd is required to facilitate this, as follows:
|
|
|
|
-object memory-backend-memfd,id=mem,size=2G
|
|
|
|
- A "x-pci-proxy-dev" device is created for each of the PCI devices emulated
|
|
in the remote process. A "socket" sub-option specifies the other end of
|
|
unix channel created by orchestrator. The "id" sub-option must be specified
|
|
and should be the same as the "id" specified for the remote PCI device
|
|
|
|
- Example commandline for QEMU is as follows:
|
|
|
|
-device x-pci-proxy-dev,id=lsi0,socket=3
|