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Hi Ric,<br>
<br>
<div class="moz-cite-prefix">On 30.03.2016 02:02, Vilbig, Ric wrote:<br>
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<div class="WordSection1">
<p class="MsoNormal"><span style="color:#1F497D">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">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).</span></p>
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VBox.log actually is showing that the VM was never fully powered up.
So the crash happens before the CPU started executing instructions.
See below, I know that this doesn't make much sense to you.<br>
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cite="mid:CDEB11797F7D624793A80A777C19829C01A6454DC2@NA-MBX-01.mgc.mentorg.com"
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<p class="MsoNormal"><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Rd 0x0a L 2 = 0x0604 // Class<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Rd 0x00 L 2 = 0x14ab // VendID<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Rd 0x02 L 2 = 0x1000 // DevID<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Wr 0x1c L 1 = 0xd0 // IOBase<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Wr 0x20 L 2 = 0xf000 // MemBase<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span
style="font-size:8.0pt;font-family:"Courier New"">PCI
CFG Root Rd 0x19 L 1 =
<b><span style="color:#C00000">0x00</span></b> //
SecBus<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">Meanwhile, does
it make sense for the BIOS to read the secondary bus
register
</span><span style="color:#1F497D">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.</span></p>
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</blockquote>
It does, but for a non-obvious reason. VirtualBox pre-configures its
PCI devices before it starts the BIOS, especially the bus numbers.
Looks like for some reason this isn't done properly (or not making
it correctly to your PCIe switch). This confuses the code, most
likely causing endless recursion and thus a stack overflow. You
should be able to use a debugger on the VM process to find out the
detail, because this is all normal userland code on the host - which
wouldn't work if it's BIOS code running inside the VM.<br>
<br>
The motivation for moving the PCI bus configuration out of the BIOS
is to some extent historic (in the old days we always fought with
the BIOS size restriction, due to the extremely bad code quality by
the BCC compiler), to some extent an optimization (it's far easier
and more efficient to do the hairy stuff in 32 bit code on the host,
and not in in the actual BIOS, which is annoying 16 bit real mode
code).<br>
<br>
Klaus<br>
<blockquote
cite="mid:CDEB11797F7D624793A80A777C19829C01A6454DC2@NA-MBX-01.mgc.mentorg.com"
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<p class="MsoNormal"><span style="color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">_____________________________________________<o:p></o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:10.0pt;color:#002060"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="color:#002060">Ric Vilbig</span></b><span
style="color:#002060"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Mentor Graphics,
Emulation Division</span><span
style="font-size:10.0pt;color:#002060"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">46871 Bayside
Parkway, Fremont CA, 94538<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Phone: 510-354-7360<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Mobile: 408-529-2365<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">email: <a
moz-do-not-send="true" href="mailto:ric_vilbig@mentor.com">
<a class="moz-txt-link-abbreviated" href="mailto:ric_vilbig@mentor.com">ric_vilbig@mentor.com</a></a><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span
style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
Vilbig, Ric
<br>
<b>Sent:</b> Tuesday, March 29, 2016 11:40<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:vbox-dev@virtualbox.org">vbox-dev@virtualbox.org</a><br>
<b>Cc:</b> Vilbig, Ric<br>
<b>Subject:</b> VM crash, NS_ERROR_FAILURE<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#002060">Hi experts,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span
style="font-size:8.0pt;font-family:"Courier
New"">> VBoxManage startvm "U14_ICH9_2"<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:8.0pt;font-family:"Courier
New"">Waiting for VM "U14_ICH9_2" to power on...<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:8.0pt;font-family:"Courier
New"">VBoxManage: error: The VM session was aborted<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:8.0pt;font-family:"Courier
New"">VBoxManage: error: Details: code
NS_ERROR_FAILURE (0x80004005), component SessionMachine,
interface ISession<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">I created
this VM from the VirtualBox GUI, v5.0.16, which I built
from the tarball at
<a moz-do-not-send="true"
href="https://www.virtualbox.org/wiki/Downloads">https://www.virtualbox.org/wiki/Downloads</a>
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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#002060">_____________________________________________<o:p></o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:10.0pt;color:#002060"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="color:#002060">Ric Vilbig</span></b><span
style="color:#002060"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Mentor Graphics,
Emulation Division<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">46871 Bayside
Parkway, Fremont CA, 94538<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Phone:
510-354-7360<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">Mobile:
408-529-2365<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060">email: <a
moz-do-not-send="true"
href="mailto:ric_vilbig@mentor.com">
<a class="moz-txt-link-abbreviated" href="mailto:ric_vilbig@mentor.com">ric_vilbig@mentor.com</a></a><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;color:#002060"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<br>
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