So I checked back on my old config- forcing X2APIC helped me on 3.x kernels only, I have not observed any effect on 4.x kernels though, so this can most-likely be disregarded for Arch.
On Tue, May 24, 2016 at 11:45 AM Spam House <kthxplz...@gmail.com> wrote: > Hey Colin, > > I am curious about this as well. Please provide more information on your > setup regarding X2APIC. > > On Sat, May 21, 2016 at 10:42 AM, Colin Godsey <crgod...@gmail.com> wrote: > >> Windows 10 forcing X2APIC: https://support.microsoft.com/en-us/kb/2303458 >> >> This helped a bunch for me at least on 4.4- I think there was some >> confusion on the correct way to signal the guest on what APIC to use, >> forcing this gave me much better %sys times. AFAIK it can also still be >> used with hyper-v APIC because that’s just the EOI para-virtualization. >> >> On Fri, May 20, 2016 at 2:28 PM Alex Williamson < >> alex.l.william...@gmail.com> wrote: >> >>> On Fri, May 20, 2016 at 11:38 AM, Nicolas Roy-Renaud < >>> nicolas.roy-renau...@ens.etsmtl.ca> wrote: >>> >>>> Did you have any issues with efifb or some other driver grabbing the >>>> gard before vfio-pci? What are your IOMMU groups like, which chard is your >>>> boot_vga, what script or method do you use to get vfio-pci to bind with >>>> your card, what's your kernel command line and what modules are included in >>>> your initramfs? >>>> >>>> I've struggled with getting my primary GPU to work correctly for a >>>> passthrough like this, and I ended up switching it up with the secondary >>>> because I simply couldn't get it to work properly (I'd keep getting >>>> something about "Invalid ROM contents") and I couldn't see my boot >>>> logs until the host driver finished loading. It's really inconvenient now >>>> becuase my motherboard is designed so that having a full-size GPU in the >>>> second PCIe slot blocks 4 SATA ports out of 6, so I need to have L-shaped >>>> cables in a bunch of places to make everything work properly. >>>> >>> >>> The boot VGA ROM is handled differently from other PCI ROMs in Linux, >>> when you read it you're actually reading a shadow copy of it placed at >>> 0xc0000, which has its roots back in the original IBM PC history. >>> Execution of the VGA ROM is allowed to modify this copy of the ROM image in >>> memory. Thus you're really not getting a pristine copy of the device ROM >>> and it can often lead to these invalid ROM contents messages. I wish we >>> provided raw access to the PCI option ROM in these cases as well. For now, >>> if you do have these sorts of invalid ROM messages, I would suggest that >>> you at least boot with the card as secondary, dump the ROM, then use that >>> collected image with the romfile= option rather than use the shadow copy. >>> I had to add some code to vfio to fix device IDs and checksums for IGD >>> assignment because of this, I don't know if there's any standard fixup we >>> can do for other vendors. Thanks, >>> >>> Alex >>> _______________________________________________ >>> vfio-users mailing list >>> vfio-users@redhat.com >>> https://www.redhat.com/mailman/listinfo/vfio-users >>> >> >> _______________________________________________ >> vfio-users mailing list >> vfio-users@redhat.com >> https://www.redhat.com/mailman/listinfo/vfio-users >> >> >
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