#!/usr/bin/env bash
# We simply check if BAR2 is present as that's where PMR or CMB is
# meant to be located under qemu. If found, print some stats then exit.

[[ $(uname -s) == Linux ]] || exit 0
# Use MSR instead?
[[ $(< /sys/class/dmi/id/chassis_vendor) == QEMU ]] || exit 0

get_bar2() {
	echo "0x$(setpci -s "$1" 0x18.L)"
}

get_size() {
	local addr=$1
	local start end type

	while IFS="- " read -r start end type; do
		start=0x$start end=0x$end
		if ((start == addr)) && [[ $type == *"$pci"* ]]; then
			printf '0x%08x:0x%08x:0x%08x\n' \
				"$start" "$end" $((end - start + 1))
			return 0
		fi
	done < /proc/iomem
	echo "unknown"
}

info() {
	local bar=$1

	local pref loc

	pref[0]=non-prefetchable
	pref[1]=prefetchable

	loc[0]=32-bit
	loc[1]="<1MiB"
	loc[2]=64-bit

	echo "${loc[(bar >> 1) & 0x3]}:${pref[bar & 1 << 3 ? 1 : 0]}:$(get_size $((bar & ~0xf)))"
}

for nvme in /sys/class/nvme/nvme*; do
	pci=$(readlink -f "$nvme/device") pci=${pci##*/}
	bar2=$(get_bar2 "$pci") || continue
	((bar2 != 0x0)) || continue
	bar=pmr
	[[ -e $nvme/cmb ]] && bar=cmb
	echo "${nvme##*/}:$pci:$(info "$bar2"):$bar"
done