[vbox-dev] VM crash, NS_ERROR_FAILURE
Klaus Espenlaub
klaus.espenlaub at oracle.com
Fri Apr 8 14:37:36 GMT 2016
Hi Ric,
On 08.04.2016 01:53, Vilbig, Ric wrote:
>
> OK, well, that gives me a lot to think about. If I were to decide
> that extending VirtualBox is my best option, do you think there would
> be interest in accepting it upstream (assuming it’s appropriately
> done), or would I likely need to maintain it myself over time?
>
For the usual definition of "appropriately done" (i.e. that it doesn't
affect the performance of normal VMs or makes our life more difficult
for no good reason) we'll integrate sensible contributions.
Klaus
> Thanks for your input, I do really appreciate it, even if it wasn’t
> quite what I hoped to hear.
>
> // Ric
>
> *From:*Michal Necasek [mailto:michal.necasek at oracle.com]
> *Sent:* Thursday, April 07, 2016 14:56
> *To:* Vilbig, Ric
> *Cc:* vbox-dev at virtualbox.org; klaus.espenlaub at oracle.com
> *Subject:* Re: [vbox-dev] VM crash, NS_ERROR_FAILURE
>
>
> The thing you're doing "wrong" is that you're trying to implement
> your own bridge device. No one else does that and the PCI/device code
> in VirtualBox simply never was architected to support that. Just like
> it was never anticipated that someone would want to implement devices
> with no 1:1 PDM device : PCI device relationship.
>
> This is just something that has never come up before. For all devices
> VirtualBox currently emulates, bridges don't matter and guest software
> doesn't care. Bridges in VirtualBox only serve to overcome the number
> of devices per PCI bus limit.
>
> You either need to restructure your approach to fit what VirtualBox
> actually supports, or modify VirtualBox.
>
> Michal
>
> ----- Original Message -----
> From: ric_vilbig at mentor.com <mailto:ric_vilbig at mentor.com>
> To: klaus.espenlaub at oracle.com <mailto:klaus.espenlaub at oracle.com>,
> vbox-dev at virtualbox.org <mailto:vbox-dev at virtualbox.org>
> Sent: Thursday, April 7, 2016 10:47:46 PM GMT +01:00 Amsterdam /
> Berlin / Bern / Rome / Stockholm / Vienna
> Subject: Re: [vbox-dev] VM crash, NS_ERROR_FAILURE
>
>
> Hi Klaus,
>
> I am blocked on my MSI issues for the moment, so I went back to look
> at this SecBus issue. I think I have figured out what is going wrong,
> and I would not be surprised if it’s also a factor in some of the
> other troubles I am having (discussed in other threads). But I am not
> sure what to do about it and would really appreciate some advice.
>
> My device constructor prepares the PCIDevice structure and then calls
> PDMDevHlpPCIRegister() to register the device. That in turn calls
> ich9pciRegisterInternal(), which adds my device to the set of bridges,
> here:
>
> pBus->papBridgesR3[pBus->cBridges] = pPciDev;
>
> pBus->cBridges++;
>
> The problem comes later when VBox calls ich9pciInitBridgeTopology()
> recursively to enumerate the busses. As it’s walking through the list
> of bridges, it makes the assumption that achInstanceData in the device
> instance is of type ICH9PCIBUS, but for my device it instead contains
> my own device property structure. This confuses the next deeper
> recursion layer, and as you correctly guessed, it enters a recursion
> loop that breaks the stack.
>
> for (uint32_t iBridge = 0; iBridge < pBus->cBridges; iBridge++)
>
> {
>
> PPCIDEVICE pBridge = pBus->papBridgesR3[iBridge];
>
> AssertMsg(pBridge && pciDevIsPci2PciBridge(pBridge),
>
> ("Device is not a PCI bridge but on the list of PCI
> bridges\n"));
>
> PICH9PCIBUS pChildBus = PDMINS_2_DATA(pBridge->pDevIns, PICH9PCIBUS);
>
> pGlobals->uBus++;
>
> ich9pciInitBridgeTopology(pGlobals, pChildBus, uBusSecondary,
> pGlobals->uBus);
>
> }
>
> It seems that if I want to register my device as a bridge, then I need
> my achInstanceData buffer to contain an ICH9PCIBUS struct. I thought
> I could just add this to the top of my own device properties
> structure, but it’s declared in DevPciIch9.cpp and therefore not
> available to me.
>
> Clearly I am doing something wrong in the way I register my bridge, so
> what is the right way to register a bridge such that its
> achInstanceData buffer contains an ICH9PCIBUS struct and also my own
> device properties as well?
>
> // RicV
>
> *From:*vbox-dev-bounces at virtualbox.org
> <mailto:vbox-dev-bounces at virtualbox.org>
> [mailto:vbox-dev-bounces at virtualbox.org] *On Behalf Of *Vilbig, Ric
> *Sent:* Saturday, April 02, 2016 10:11
> *To:* Klaus Espenlaub; vbox-dev at virtualbox.org
> <mailto:vbox-dev at virtualbox.org>
> *Subject:* Re: [vbox-dev] VM crash, NS_ERROR_FAILURE
>
> Thank you Klaus. I will return to this SecBus issue after I get past
> the MSI issue that I am having, and this information will certainly be
> helpful. At the moment I have a work around (hack) for the SecBus
> problem which seems to be working, whereas the MSI problem has me
> blocked. Once I get past that, I should have time to figure out a
> proper solution for the SecBus problem.
>
> // RicV
>
> *From:*Klaus Espenlaub [mailto:klaus.espenlaub at oracle.com]
> *Sent:* Friday, April 01, 2016 08:51
> *To:* vbox-dev at virtualbox.org <mailto:vbox-dev at virtualbox.org>
> *Subject:* Re: [vbox-dev] VM crash, NS_ERROR_FAILURE
>
> Hi Ric,
>
> On 30.03.2016 02:02, Vilbig, Ric wrote:
>
> 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).
>
> 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.
>
> 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.
>
> 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.
>
> 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).
>
> Klaus
>
> _____________________________________________
>
> **
>
> *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 <mailto: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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