#!/bin/bash

PLAT_FUNCS="/usr/local/sbin/nv_scripts/plat_funcs.bash"
GENERAL_FUNCS="/usr/local/sbin/nv_scripts/general_funcs.bash"
CONF_FILE="/etc/default/grub.d/iommu.cfg"
OLD_CONF_FILE="/etc/default/grub.d/iommu-pt.cfg"

. "${GENERAL_FUNCS}"
. "${PLAT_FUNCS}"

UPDATE_GRUB=false

if [ -e  $OLD_CONF_FILE ]; then
    rm $OLD_CONF_FILE
    UPDATE_GRUB=true
fi

if ! skip_platform_detection && plat_needs_iommu_pt; then
    IOMMU_PT=" iommu=pt"
    UPDATE_GRUB=true
else
    IOMMU_PT=""
fi

# Model: 207 is Emerald Rapids (EMR)
# Model: 173 is Granite Rapids (GNR)
#
# 10/30/2024: The current recommendation for better performance
# is that intel_iommu=on should only be enabled on platforms with
# the Emerald Rapids CPU.
# 08/22/2025: Recommendation is to add "intel_iommu=on iommu=pt"
# for Intel CPUs which is EMR and GNR.

EMR_CPUTYPE="207"
GNR_CPUTYPE="173"
CPUTYPE=$(lscpu | grep "Model:" | awk '{print $2}')

# Check if CPU is either EMR or GNR
if [ "$CPUTYPE" == "$EMR_CPUTYPE" ] || [ "$CPUTYPE" == "$GNR_CPUTYPE" ]; then
    # Force both settings for GNR and EMR CPUs
    INTEL_IOMMU=" intel_iommu=on"
    IOMMU_PT=" iommu=pt"  # Override with forced setting for GNR/EMR
    UPDATE_GRUB=true
else
    INTEL_IOMMU=""
fi

if $UPDATE_GRUB; then
    if [[ "$IOMMU_PT" != "" || "$INTEL_IOMMU" != "" ]]; then
        echo "GRUB_CMDLINE_LINUX=\"\$GRUB_CMDLINE_LINUX${IOMMU_PT}${INTEL_IOMMU}\"" > ${CONF_FILE}
    fi
    /usr/sbin/update-grub ||:
fi

exit 0