Bug 534020

Summary: Some questions for SR-IOV in RedHat 5.4
Product: Red Hat Enterprise Linux 5 Reporter: peter.chiu
Component: doc-Virtualization_GuideAssignee: Christopher Curran <ccurran>
Status: CLOSED CURRENTRELEASE QA Contact: Joshua Wulf <jwulf>
Severity: medium Docs Contact:
Priority: low    
Version: 5.4CC: bburns, lcarlon, mhideo
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-04-07 01:41:22 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description peter.chiu 2009-11-10 06:40:14 UTC
Description of problem:
1.      Why host OS do not use resources that BIOS assign in guest OS
2.      In current situation, why host OS enable SR-IOV do not according to the BIOS enable/disable SR_IOV.
3.    When in guest OS, I used lspci command to dump the configuration space of 82576 VF Ethernet Controller that I assigned to guest OS.
I noticed that the guest OS did not use the MMIO resources that BIOS assigned to 82576 VF Ethernet Controller and the sizes even less than it required.
For example, when I wrote 0xFFFFFFFF to VF BAR0 ~ VF BAR5 in physical 82576 Ethernet Controller, it return 0xc000 size that VF BAR0 and VF BAR3 needed,
But when I came into guest OS and saw 82576 VF Ethernet Controller BAR0 and BAR3 it show 0xc4004000 and 0xc4008000, the size was less than VF BAR need

Version-Release number of selected component (if applicable):
RedHat Enterprise5.4 

How reproducible:

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Comment 1 Christopher Curran 2010-03-29 06:30:28 UTC
1. Not sure what you mean here. Disabling SR-IOV VFs so that the VF can be used by the guest is covered in the updated Virtualization Guide.

2. Covered in the Virtualization Guide.

3. The PCI devices names are not necessarily the same. Guests and hows have different naming and assignment methods.