Re: [Qemu-devel] [V6 0/4] AMD IOMMU

[Jan Kiszka <jan.kiszka@web.de>]

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On 2016-02-22 12:05, David Kiarie wrote:
> On Mon, Feb 22, 2016 at 10:29 AM, Jan Kiszka <jan.kiszka@web.de> wrote:
>> On 2016-02-22 06:57, David Kiarie wrote:
>>> On Sun, Feb 21, 2016 at 11:20 PM, Jan Kiszka <jan.kiszka@web.de> wrote:
>>>> On 2016-02-21 19:10, David Kiarie wrote:
>>>>> Hello there,
>>>>>
>>>>> Repost, AMD IOMMU patches version 6.
>>>>>
>>>>> Changes since version 5
>>>>>  -Fixed macro formating issues
>>>>>  -changed occurences of IO MMU to IOMMU for consistency
>>>>>  -Fixed capability registers duplication
>>>>>  -Rebased to current master
>>>>
>>>> I suspect this still has some subtle bugs: I'm running the patches over
>>>> master with standard Linux distro as guest, full desktop, and I'm
>>>> getting sporadic segfaults of arbitrary programs. These disappear once I
>>>> disable the IOMMU or switch to the Intel version.
>>>
>>> Is this L1 guest or L2 guest ? - haven't got any such so far.
>>
>> It's L1 only.
>>
>>>
>>>>
>>>> How did you test so far?
>>>
>>> I mainly test by logging. I've tested L1 without any iommu-related
>>> command line parameters and with L1 with 'iommu=1 iommu=pt'. L2 guest;
>>> passed-through a device checked it's working correctly, that all.
>>> These guests barely have any load though.
>>
>> I quickly reproduced the issue by starting some "heavier" applications,
>> a browser or an office suite. Something is apparently always corrupted
>> then, data or code, thus the crashes.
> 
> Can't reproduce this issue with my ubuntu/debian VMs. Are you using
> any iommu-related command line parameters ?

This is my command line:

qemu-system-x86_64
    -drive file=/path/to/64-bit-linux.img,discard=unmap,if=none,id=disk
    -device ide-hd,drive=disk -snapshot -m 1G -enable-kvm -smp 4
    -machine q35,iommu=amd

64-bit guest userland, linus.git head guest kernel.

Jan



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