scripts: Add helper script for looking up PMR info under qemu

Added mainly to verify if the PMR setup on the VM is correct.

Example of an output with PMR device size of 32M configured for
two nvme devices, and one nvme device with 128M CMB.

[root@fedora31-cloud-1614680581-9ba06c102 ~]# /tmp/get-pmr
nvme0:0000:00:04.0:64-bit:prefetchable:0xf0000000:0xf7ffffff:0x08000000:cmb
nvme1:0000:00:05.0:64-bit:prefetchable:0xf8000000:0xf9ffffff:0x02000000:pmr
nvme2:0000:00:06.0:64-bit:prefetchable:0xfa000000:0xfbffffff:0x02000000:pmr

Signed-off-by: Michal Berger <michalx.berger@intel.com>
Change-Id: I522cebd8b5a16f8a37c6e0e01a0288fb310467fb
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7019
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

scripts/get-pmr

@@ -0,0 +1,50 @@
+#!/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