Re: [PATCH] amd iommu: Dump flags of IO page faults

[Wei Wang <wei.wang2@amd.com>]

On 09/06/2012 03:50 PM, Sander Eikelenboom wrote:
>
> Thursday, September 6, 2012, 3:32:51 PM, you wrote:
>
>> On 09/06/2012 12:59 AM, Sander Eikelenboom wrote:
>>>
>>> Wednesday, September 5, 2012, 4:42:42 PM, you wrote:
>>>
>>>> Hi Jan,
>>>> Attached patch dumps io page fault flags. The flags show the reason of
>>>> the fault and tell us if this is an unmapped interrupt fault or a DMA fault.
>>>
>>>> Thanks,
>>>> Wei
>>>
>>>> signed-off-by: Wei Wang<wei.wang2@amd.com>
>>>
>>>
>>> I have applied the patch and the flags seem to differ between the faults:
>>>
>>> AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x0a06, fault address = 0xc2c2c2c0, flags = 0x000
>>> (XEN) [2012-09-05 20:54:16] AMD-Vi: IO_PAGE_FAULT: domain = 0, device id = 0x0a06, fault address = 0xc2c2c2c0, flags = 0x000
>>> (XEN) [2012-09-05 20:54:16] AMD-Vi: IO_PAGE_FAULT: domain = 14, device id = 0x0700, fault address = 0xa8d339e0, flags = 0x020
>>> (XEN) [2012-09-05 20:54:16] AMD-Vi: IO_PAGE_FAULT: domain = 14, device id = 0x0700, fault address = 0xa8d33a40, flags = 0x020
>
>> OK, so they are not interrupt requests. I guess further information from
>> your system would be helpful to debug this issue:
>> 1) xl info
>> 2) xl list
>> 3) lscpi -vvv (NOTE: not in dom0 but in your guest)
>> 4) cat /proc/iomem (in both dom0 and your hvm guest)
>
> dom14 is not a HVM guest,it's a PV guest.

Ah, I see. PV guest is quite different than hvm, it does use p2m tables 
as io page tables. So no-sharept option does not work in this case. PV 
guests always use separated io page tables. There might be some 
incorrect mappings on the page tables. I will check this on my side.

Thanks,
Wei

> I will try to make a complete package, and try with one pv domain only where the devices are being passed through just to simplify the setup.
>
>
>> * I would also like to know the symptoms of device 0x0700 when IO_PF
>> happened. Did it stop working?
>
> Yes it stops working, the video capture just freezes, but the driver doesn't bail out.
> For the USB controller (0x0a06) it starts to give errors for usbdev_open in the guest.
>
>> (BTW: I copied a few options from your boot cmd line and it worked with
>> my RD890 system
>
>> dom0_mem=1024M,max:1024M loglvl=all loglvl_guest=all console_timestamps
>> cpuidle cpufreq=xen noreboot debug lapic=debug apic_verbosity=debug
>> apic=debug iommu=on,verbose,debug,no-sharept
>
>> * so, what OEM board you have?)
>
> MSI 890FXA-GD70
>
>> Also from your log, these lines looks very strange:
>
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xd5, mfn=0xa4a11
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xd7, mfn=0xa4a0f
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xd9, mfn=0xa4a0d
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xdb, mfn=0xa4a0b
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xdd, mfn=0xa4a09
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xdf, mfn=0xa4a07
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xe1, mfn=0xa4a05
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xe3, mfn=0xa4a03
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xe5, mfn=0xa4a01
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xe7, mfn=0xa463f
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xe9, mfn=0xa463d
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xeb, mfn=0xa463b
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xed, mfn=0xa4639
>> (XEN) [2012-09-04 15:54:35] hvm.c:2435:d15 guest attempted write to
>> read-only memory page. gfn=0xef, mfn=0xa4637
>> (XEN) [2012-09-04 16:13:56] AMD-Vi: IO_PAGE_FAULT: domain = 0, device id
>> = 0x0a06, fault address = 0xc2c2c2c0
>> (XEN) [2012-09-04 16:13:56] AMD-Vi: IO_PAGE_FAULT: domain = 14, device
>> id = 0x0700, fault address = 0xa90f8300
>> (XEN) [2012-09-04 16:13:56] AMD-Vi: IO_PAGE_FAULT: domain = 14, device
>> id = 0x0700, fault address = 0xa90f8340
>> (XEN) [2012-09-04 16:13:56] AMD-Vi: IO_PAGE_FAULT: domain = 14, device
>> id = 0x0700, fault address = 0xa90f8380
>> (XEN) [2012-09-04 16:13:56] AMD-Vi: IO_PAGE_FAULT: domain = 14, device
>> id = 0x0700, fault address = 0xa90f83c0
>
>> * they are just followed by the IO PAGE fault. Do you know where are
>> they from? Your video card driver maybe?
>
>  From a HVM domain with a old (3.0.3) kernel, but the faults also occur without this domain being started.
>
>
>> Thanks,
>> Wei
>
>
>>> Complete xl dmesg and lspci -vvvknn attached.
>>>
>>> Thx
>>>
>>> --
>>> Sander
>
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