On 2012-09-28 17:50, Alex Williamson wrote: > On Fri, 2012-09-28 at 10:12 +0200, Jan Kiszka wrote: >> On 2012-09-27 21:18, Alex Williamson wrote: >>> On Thu, 2012-09-27 at 20:43 +0200, Martin Wolf wrote: >>>> thank you for the information. >>>> >>>> i will try what you mentioned... >>>> do you have some additional information about rebooting a VM with a >>>> passed through videocard? >>>> (amd / ati 7870) >>> >>> I don't. Is the bsod on reboot only or does it also happen on shutdown? >>> There's a slim chance it could be traced by enabling debug in the >>> pci-assign driver and analyzing what the guest driver is trying to do. >>> I'm hoping that q35 chipset support might resolve some issues with vga >>> assignment as it exposes a topology that looks a bit more like one that >>> a driver would expect on physical hardware. Thanks, >> >> From our attempts to get more working than what NVIDIA Quadro cards >> support officially, my own experiments with q35 in this context and our >> discussions with NVIDIA, I'm pretty skeptical that this chipset will >> make a difference here. Most problems are due to those non-standard side >> channels to configure the hardware, memory mappings etc. And getting >> this working requires either cooperation of the vendor or *a lot* of >> reverse engineering. > > I heard from an nvidia guy that the driver behaves differently depending > on whether it finds an upstream express port, so we're probably causing > ourselves more problems if it's trying to run in AGP mode. May be a point for the low- to mid-range cards. It does not apply to the "virtualization-ready" Quadro series according to our information back then. > There was > also a lot of FUD in Xen (maybe justified) around how the BIOS > determines the memory ranges and whether it bypasses the PCI BARs and > gets them directly. That means some cards may require identity mapping > to work. It seems like the very high-end cards are possibly fixing > this, but they're far more expensive than I can justify. Thanks, Yes, that is what makes them virtualization ready. But they also come with limitations. So far, you can't pass-through a primary card or use it for early boot messages of the guest as the BIOS is not ready for that - without identity mapping or even more. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
