Date:   Wed, 22 Nov 2017 17:54:36 +0100
From:   Christian König <christian.koenig@....com>
To:     Boris Ostrovsky <boris.ostrovsky@...cle.com>, helgaas@...nel.org,
        linux-pci@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, amd-gfx@...ts.freedesktop.org,
        xen-devel <xen-devel@...ts.xen.org>
Subject: Re: [PATCH v9 4/5] x86/PCI: Enable a 64bit BAR on AMD Family 15h
 (Models 30h-3fh) Processors v5

Am 22.11.2017 um 17:24 schrieb Boris Ostrovsky:
> On 11/22/2017 05:09 AM, Christian König wrote:
>> Am 21.11.2017 um 23:26 schrieb Boris Ostrovsky:
>>> On 11/21/2017 08:34 AM, Christian König wrote:
>>>> Hi Boris,
>>>>
>>>> attached are two patches.
>>>>
>>>> The first one is a trivial fix for the infinite loop issue, it now
>>>> correctly aborts the fixup when it can't find address space for the
>>>> root window.
>>>>
>>>> The second is a workaround for your board. It simply checks if there
>>>> is exactly one Processor Function to apply this fix on.
>>>>
>>>> Both are based on linus current master branch. Please test if they fix
>>>> your issue.
>>> Yes, they do fix it but that's because the feature is disabled.
>>>
>>> Do you know what the actual problem was (on Xen)?
>> I still haven't understood what you actually did with Xen.
>>
>> When you used PCI pass through with those devices then you have made a
>> major configuration error.
>>
>> When the problem happened on dom0 then the explanation is most likely
>> that some PCI device ended up in the configured space, but the routing
>> was only setup correctly on one CPU socket.
> The problem is that dom0 can be (and was in my case() booted with less
> than full physical memory and so the "rest" of the host memory is not
> necessarily reflected in iomem. Your patch then tried to configure that
> memory for MMIO and the system hang.
>
> And so my guess is that this patch will break dom0 on a single-socket
> system as well.

Oh, thanks!

I've thought about that possibility before, but wasn't able to find a 
system which actually does that.

May I ask why the rest of the memory isn't reported to the OS?

Sounds like I can't trust Linux resource management and probably need to 
read the DRAM config to figure things out after all.

Thanks a lot for this information,
Christian.

>
> -boris
>
>> Regards,
>> Christian.
>>
>>> Thanks.
>>> -boris
>>>
>>>> Thanks for the help,
>>>> Christian.
>>>>
>>>> Am 20.11.2017 um 17:33 schrieb Boris Ostrovsky:
>>>>> On 11/20/2017 11:07 AM, Christian König wrote:
>>>>>> Am 20.11.2017 um 16:51 schrieb Boris Ostrovsky:
>>>>>>> (and then it breaks differently as a Xen guest --- we hung on the
>>>>>>> last
>>>>>>> pci_read_config_dword(), I haven't looked at this at all yet)
>>>>>> Hui? How does this fix applies to a Xen guest in the first place?
>>>>>>
>>>>>> Please provide the output of "lspci -nn" and explain further what is
>>>>>> your config with Xen.
>>>>>>
>>>>>>
>>>>> This is dom0.
>>>>>
>>>>> -bash-4.1# lspci -nn
>>>>> 00:00.0 Host bridge [0600]: ATI Technologies Inc RD890 Northbridge
>>>>> only
>>>>> dual slot (2x16) PCI-e GFX Hydra part [1002:5a10] (rev 02)
>>>>> 00:00.2 Generic system peripheral [0806]: ATI Technologies Inc Device
>>>>> [1002:5a23]
>>>>> 00:0d.0 PCI bridge [0604]: ATI Technologies Inc RD890 PCI to PCI
>>>>> bridge
>>>>> (external gfx1 port B) [1002:5a1e]
>>>>> 00:11.0 SATA controller [0106]: ATI Technologies Inc SB700/SB800 SATA
>>>>> Controller [AHCI mode] [1002:4391]
>>>>> 00:12.0 USB Controller [0c03]: ATI Technologies Inc SB700/SB800 USB
>>>>> OHCI0 Controller [1002:4397]
>>>>> 00:12.1 USB Controller [0c03]: ATI Technologies Inc SB700 USB OHCI1
>>>>> Controller [1002:4398]
>>>>> 00:12.2 USB Controller [0c03]: ATI Technologies Inc SB700/SB800 USB
>>>>> EHCI
>>>>> Controller [1002:4396]
>>>>> 00:13.0 USB Controller [0c03]: ATI Technologies Inc SB700/SB800 USB
>>>>> OHCI0 Controller [1002:4397]
>>>>> 00:13.1 USB Controller [0c03]: ATI Technologies Inc SB700 USB OHCI1
>>>>> Controller [1002:4398]
>>>>> 00:13.2 USB Controller [0c03]: ATI Technologies Inc SB700/SB800 USB
>>>>> EHCI
>>>>> Controller [1002:4396]
>>>>> 00:14.0 SMBus [0c05]: ATI Technologies Inc SBx00 SMBus Controller
>>>>> [1002:4385] (rev 3d)
>>>>> 00:14.3 ISA bridge [0601]: ATI Technologies Inc SB700/SB800 LPC host
>>>>> controller [1002:439d]
>>>>> 00:14.4 PCI bridge [0604]: ATI Technologies Inc SBx00 PCI to PCI
>>>>> Bridge
>>>>> [1002:4384]
>>>>> 00:14.5 USB Controller [0c03]: ATI Technologies Inc SB700/SB800 USB
>>>>> OHCI2 Controller [1002:4399]
>>>>> 00:18.0 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1600]
>>>>> 00:18.1 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1601]
>>>>> 00:18.2 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1602]
>>>>> 00:18.3 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1603]
>>>>> 00:18.4 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1604]
>>>>> 00:18.5 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1605]
>>>>> 00:19.0 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1600]
>>>>> 00:19.1 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1601]
>>>>> 00:19.2 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1602]
>>>>> 00:19.3 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1603]
>>>>> 00:19.4 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1604]
>>>>> 00:19.5 Host bridge [0600]: Advanced Micro Devices [AMD] Device
>>>>> [1022:1605]
>>>>> 01:04.0 VGA compatible controller [0300]: Matrox Graphics, Inc. MGA
>>>>> G200eW WPCM450 [102b:0532] (rev 0a)
>>>>> 02:00.0 Ethernet controller [0200]: Intel Corporation 82576 Gigabit
>>>>> Network Connection [8086:10c9] (rev 01)
>>>>> 02:00.1 Ethernet controller [0200]: Intel Corporation 82576 Gigabit
>>>>> Network Connection [8086:10c9] (rev 01)
>>>>> -bash-4.1#
>>>>>
>>>>>
>>>>> -boris

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