[vfio-users] Physical disk passthrough and OVMF
Dan Ziemba
zman0900 at gmail.com
Sat Mar 26 22:00:34 UTC 2016
On Fri, 2016-03-25 at 01:10 +0300, Blank Field wrote:
> Hello again, fellow subscribers.
>
> Since 4.3.X kernels I am experiencing some strange problems with disk
> IO.
>
> I am passing through the whole /dev/sda(since i also dualboot into
> that system for some weird software or hardware) to my VM, and since
> recent versions of kernel the VM gets stuck in an endless loop,
> consuming 100% one core.
>
> The ISA debug console says stuff like:
> PartitionValidMbr: Bad MBR partition size EndingLBA(D99299D3) >
> LastLBA(31FFF)
>
> The thing is that the disk in question has nothing to do with MBR, it
> is formatted into GPT.
> I can't pinpoint the source of that weird D99299D3 number.
>
> That kind of error happens for every partition detected.
>
> Device Start End Sectors Size Type
> /dev/sda1 2048 1171875000 1171872953 558.8G Microsoft basic
> data
> /dev/sda2 1171875840 1172080639 204800 100M EFI System
> /dev/sda3 1172080640 1172342783 262144 128M Microsoft reserved
> /dev/sda4 1172342784 1465145343 292802560 139.6G Microsoft basic
> data
> /dev/sda5 1465145344 1953525134 488379791 232.9G Microsoft basic
> data
> That looks like a valid partition table for me. Moreover, the fact
> that i am able to boot an UEFI-capable system bare-metal confirms
> that
> the partition table is correct.
>
> I remember i've seen some related messages on the list in february or
> something, but they only stated the existence of this error.
>
> Have any of you seen stuff like that? If so, how do you live with it?
>
> Maybe i should write to edk2-devel mailing list for this, because it
> isn't much related to VFIO, but normal qemu folks rarely sacrifice
> the
> whole disk to a VM.
>
> Versions:
> QEMU emulator version 2.4.1 (qemu-2.4.1-7.fc23)
> kernel 4.4.5-300.fc23.x86_64(doesn't matter much from 4.3.X)
> edk2.git-0-20160311.b1594.gf6326d1.x86_64
>
A lot of people had problems booting with OVMF with kernels 4.2 and
4.3. It's fixed for myself and I think most others with 4.4, but I
think you may need fairly recent qemu and ovmf versions. Looks like
your OVMF is new enough if that date means what I think it does, but
you should try upgrading to qemu 2.5.
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