#!/bin/bash
#
# Copyright (c) 2019 Wind River Systems, Inc.
#
# SPDX-License-Identifier: Apache-2.0
#
#  This script logs to user.log
#
# The script is called with the following parameters
#   e.g. /etc/libvirt/hooks/qemu <guest_name> <operation>
#

# Save the instance's XML. The guest qemu hook scrips are given the full XML description
# on their stdin.
XML_DATA=$(/bin/cat)

GUEST_NAME=$1

shift
OPERATION=$*

logger -p info -t ${0} "hook qemu file guest ${GUEST_NAME} with operation ${OPERATION}"

# CPU Low latency setup:
#
# A cpu is set to low latency when:
# 1) host is set to subfunction=lowlatency in platform.conf and
# 2) domain has dedicated pinning
#
# example of <cputune> section when domain has dedicated pinning:
# <cputune>
#     <vcpupin vcpu='0' cpuset='5'/>
#     <vcpupin vcpu='1' cpuset='6'/>
#     <vcpupin vcpu='2' cpuset='7'/>
#     <emulatorpin cpuset='5'/>
# </cputune>
#
# example of <cputune> section when domain has shared pinning:
# <cputune>
#     <shares>4096</shares>
#     <vcpupin vcpu='0' cpuset='5-21'/>
#     <vcpupin vcpu='1' cpuset='5-21'/>
#     <vcpupin vcpu='2' cpuset='5-21'/>
#     <vcpupin vcpu='3' cpuset='5-21'/>
#     <emulatorpin cpuset='5-21'/>
# </cputune>

if [ "${OPERATION}" == "prepare begin -" ] || [ "${OPERATION}" == "stopped end -" ]; then
   # verify this host is set as lowlatency
   lowlat=$(cat /etc/platform/platform.conf 2>/dev/null | grep -E 'subfunction.*lowlatency')
   if [ -n "${lowlat}" ]; then
      # grab the <cputune> settings and remove single quotes
      CPUTUNE=$(echo ${XML_DATA} | grep -oP '(?<=<cputune).*?(?=</cputune>)' | sed "s/'//g")

      # grab all cpuset pinned to a unique CPU. Treat them as dedicated
      CPUSET=($(echo ${CPUTUNE} | grep -oP '(?<=cpuset=)[^/]+(?=.+emulator)' | grep -vP '[^0-9]'))
      if [ ${#CPUSET[@]} -ne 0 ]; then
          # convert to a comma separated list
         CPUS=$(IFS=, ; echo "${CPUSET[*]}")
         if [ "${OPERATION}" == "prepare begin -" ]; then
            /usr/bin/set-cpu-wakeup-latency.sh "low" "${CPUS}"
         else
            /usr/bin/set-cpu-wakeup-latency.sh "high" "${CPUS}"
         fi
      fi
   fi
fi

exit 0