pci: document info qtree to get pci device info

README.adoc

@@ -3909,6 +3909,37 @@ In our case for example, we see:
 
 which we identify as being `edu` and `pci_min` respectively by the magic numbers: `1234:11e?`
 
+Alternatively, we can also do use the QEMU monitor:
+
+....
+echo 'info qtree' | ./qemumonitor
+....
+
+which gives:
+
+....
+      dev: lkmc_pci_min, id ""
+        addr = 07.0
+        romfile = ""
+        rombar = 1 (0x1)
+        multifunction = false
+        command_serr_enable = true
+        x-pcie-lnksta-dllla = true
+        x-pcie-extcap-init = true
+        class Class 00ff, addr 00:07.0, pci id 1234:11e9 (sub 1af4:1100)
+        bar 0: mem at 0xfeb54000 [0xfeb54007]
+      dev: edu, id ""
+        addr = 06.0
+        romfile = ""
+        rombar = 1 (0x1)
+        multifunction = false
+        command_serr_enable = true
+        x-pcie-lnksta-dllla = true
+        x-pcie-extcap-init = true
+        class Class 00ff, addr 00:06.0, pci id 1234:11e8 (sub 1af4:1100)
+        bar 0: mem at 0xfea00000 [0xfeafffff]
+....
+
 Read the configuration registers as binary:
 
 ....