/etc/default/grub

[ben@centos ~]$ cat /etc/default/grub
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL_OUTPUT="console"
GRUB_CMDLINE_LINUX="rd.lvm.lv=centos_centos/root vconsole.font=latarcyrheb-sun16 crashkernel=auto  vconsole.keymap=us rd.lvm.lv=centos_centos/swap rhgb rd.driver.blacklist=nouveau nouveau.modeset=0 iommu=pt iommu=1 vfio_iommu_type1.allow_unsafe_interrupts=1 rdblacklist=nouveau pci-stub. ids=10de:1200, 10de:0e0c quiet"
GRUB_DISABLE_RECOVERY="true"