docs: vtd.txt doc change

Added a note on conventional PCI device passthrough.

Signed-off-by: Allen Kay <allen.m.kay@intel.com>

diff --git a/docs/misc/vtd.txt b/docs/misc/vtd.txt
index c33074b84a0da95c7ca613639c66bab6b5c1bf5e..1d4e68ce5a42b88e662512e1fb26d4c15b78f5cb 100644 (file)
--- a/docs/misc/vtd.txt
+++ b/docs/misc/vtd.txt
@@ -2,7 +2,7 @@ Title   : How to do PCI Passthrough with VT-d
 Authors : Allen Kay    <allen.m.kay@intel.com>
           Weidong Han  <weidong.han@intel.com>
 Created : October-24-2007
-Updated : October-24-2007
+Updated : December-11-2007
 
 How to turn on VT-d in Xen
 --------------------------
@@ -22,7 +22,7 @@ How to turn on VT-d in Xen
 title Xen-Fedora Core (2.6.18-xen)
         root (hd0,0)
         kernel /boot/xen.gz com1=115200,8n1 console=com1 vtd=1
-        module /boot/vmlinuz-2.6.18.8-xen root=LABEL=/ ro console=tty0 console=ttyS0,115200,8n1 pciback.hide=(01:00.0)(03:00.0) pciback.verbose_request=1 apic=debug maxcpus=1
+        module /boot/vmlinuz-2.6.18.8-xen root=LABEL=/ ro console=tty0 console=ttyS0,115200,8n1 pciback.hide=(01:00.0)(03:00.0) pciback.verbose_request=1 apic=debug
         module /boot/initrd-2.6.18-xen.img
 
 12) reboot system
@@ -32,6 +32,15 @@ title Xen-Fedora Core (2.6.18-xen)
     "ifconfig" to see if IP address has been assigned to NIC devices.
 
 
+Caveat on Conventional PCI Device Passthrough
+---------------------------------------------
+
+VT-d spec specifies that all conventional PCI devices behind a
+PCIe-to-PCI bridge have to be assigned to the same domain.
+
+PCIe devices do not have this restriction.
+
+
 VT-d Enabled Systems
 --------------------
 
@@ -48,3 +57,4 @@ http://www.dell.com/content/products/category.aspx/optix?c=us&cs=555&l=en&s=biz
 
 - HP Compaq:  DC7800
 http://h10010.www1.hp.com/wwpc/us/en/en/WF04a/12454-12454-64287-321860-3328898.html
+