[vbox-dev] VM crash, NS_ERROR_FAILURE

[Vilbig, Ric]

Hi,

I obviously carried on with my investigation after sending the original email, and have figured out what is triggering this abort (not really fair to call it a crash).

When the BIOS starts initializing the PCI Configuration space for my PCIe switch, it reads the secondary bus register (PCI CFG 0x19) before it's been initialized, so the device model is returning 0.  This puts the BIOS into a loop, repeating the following over 5000 times before aborting the VM session.

PCI CFG Root  Rd 0x0a L 2 = 0x0604     // Class
PCI CFG Root  Rd 0x00 L 2 = 0x14ab     // VendID
PCI CFG Root  Rd 0x02 L 2 = 0x1000     // DevID
PCI CFG Root  Wr 0x1c L 1 = 0xd0       // IOBase
PCI CFG Root  Wr 0x20 L 2 = 0xf000     // MemBase
PCI CFG Root  Rd 0x19 L 1 = 0x00       // SecBus

If I intercept the secondary bus register read, and return a 3 instead of reading 0 from RTL, then it carries on with root configuration and my VM boots and runs correctly.  It's not detecting the downstream end point, but that is a separate issue.

Meanwhile, does it make sense for the BIOS to read the secondary bus register before it's been initialized?  It seems like that register should be set up as the BIOS proceeds through the enumeration.  That is what the VM with PIIX3 chipset does.

_____________________________________________

Ric Vilbig
Mentor Graphics, Emulation Division
46871 Bayside Parkway, Fremont CA, 94538
Phone:  510-354-7360
Mobile: 408-529-2365
email:  ric_vilbig at mentor.com<mailto:ric_vilbig at mentor.com>





From: Vilbig, Ric
Sent: Tuesday, March 29, 2016 11:40
To: vbox-dev at virtualbox.org
Cc: Vilbig, Ric
Subject: VM crash, NS_ERROR_FAILURE

Hi experts,

I would like to ask for some help to figure out why a certain VM crashes on start-up.  Although the problem is evidently induced by my PDM plug-in, the crash does not appear to be happening therein.  I need some help to root cause where VBox is aborting the VM session.

>  VBoxManage startvm "U14_ICH9_2"
Waiting for VM "U14_ICH9_2" to power on...
VBoxManage: error: The VM session was aborted
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component SessionMachine, interface ISession

I created this VM from the VirtualBox GUI, v5.0.16, which I built from the tarball at https://www.virtualbox.org/wiki/Downloads and am running on an Ubuntu 14 host.  Then I switched the chipset to ICH9, then I installed Ubuntu 14 as the guest.  The VM runs well, until I plug my virtual device model into PDM (it's a PCIe switch with downstream endpoint).  After plugging in my virtual device, the VM crashes as shown above.

I tracked down everywhere NS_ERROR_FAILURE is mentioned in the sources.  I found that DirectoryServiceProvider::GetFile() returns that error twice, right away, but that is also true in the working case when my device is unplugged.  In no other place is that specific error ever returned or asserted.  However, I found that E_FAIL is #defined to NS_ERROR_FAILURE, and there are hundreds of references to E_FAIL, so I gave up trying to instrument them all.

I need some help to root cause this problem.  Log files show that it is getting as far as BIOS starting to initialize the switch, apparently stuck in a loop doing that, but then lights out with no trail that I can follow.

Log files are attached.  Lines bearing the "RicV" prefix were instrumented by me to investigate this problem.  Lines bearing the "RemDev" prefix are coming from my PDM plug-in.

Thanks,

_____________________________________________

Ric Vilbig
Mentor Graphics, Emulation Division
46871 Bayside Parkway, Fremont CA, 94538
Phone:  510-354-7360
Mobile: 408-529-2365
email:  ric_vilbig at mentor.com<mailto:ric_vilbig at mentor.com>


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