Re: [Xen-users] pvgrub2(-like?) booting methods for PVHv2 guests

[Hans van Kranenburg <hans@xxxxxxxxxxx>]

On 02/07/2018 02:55 PM, Juergen Gross wrote:
> On 07/02/18 14:14, Hans van Kranenburg wrote:
>> On 02/07/2018 09:37 AM, Juergen Gross wrote:
>>> On 06/02/18 19:34, Hans van Kranenburg wrote:
>>>> On 02/06/2018 06:02 PM, Juergen Gross wrote:
>>>>> On 06/02/18 17:53, Hans van Kranenburg wrote:
>>>>>> On 02/06/2018 09:35 AM, Juergen Gross wrote:
>>>>>>> On 05/02/18 20:49, Hans van Kranenburg wrote:
>>>>>>>> On 01/25/2018 03:31 PM, Juergen Gross wrote:
>>>>>>>>> On 25/01/18 15:12, Hans van Kranenburg wrote:
>>>>>>>>>> On 01/25/2018 02:46 PM, Hans van Kranenburg wrote:
>>>>>>>>>>> On 25/01/2018 13:29, Juergen Gross wrote:
>>>>>>>>>>>> On 25/01/18 13:19, Andy Smith wrote:
>>>>>>>>>>>>> Hi Hans,
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Thu, Jan 25, 2018 at 12:39:56PM +0100, Hans van Kranenburg 
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>> And now I get console output and things happen. Only it can't 
>>>>>>>>>>>>>> find the disk.
>>>>>>>>>>>>>
>>>>>>>>>>>>> I was trying similar thing (4.10 and PVH) and also ended up with a
>>>>>>>>>>>>> guest with no block devices. I reported this on grub-devel:
>>>>>>>>>>>>>
>>>>>>>>>>>>>     
>>>>>>>>>>>>> <http://lists.gnu.org/archive/html/grub-devel/2018-01/msg00018.html>
>>>>>>>>>>>>>
>>>>>>>>>>>>> as I was thinking this was not a Xen problem since same thing 
>>>>>>>>>>>>> boots
>>>>>>>>>>>>> okay outside grub with direct kernel boot.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Juergen did reply and said I needed this kernel patch in the 
>>>>>>>>>>>>> guest:
>>>>>>>>>>>>>
>>>>>>>>>>>>>     
>>>>>>>>>>>>> <https://lists.xen.org/archives/html/xen-devel/2017-11/msg01681.html>
>>>>>>>>>>>>>
>>>>>>>>>>>>> But I think you have this don't you?
>>>>>>>>>>>
>>>>>>>>>>> Yes, see my earlier mail with all the steps that I did, step 6.
>>>>>>>>>>>
>>>>>>>>>>>> As the ACPI tables are found, I'd say yes. :-)
>>>>>>>>>>>
>>>>>>>>>>> dmesg output is pretty different when I boot directly with the 
>>>>>>>>>>> kernel
>>>>>>>>>>> and initrd copied on the dom0.
>>>>>>>>>>>
>>>>>>>>>>> Remember, it's the same kernel/initrd, and without grub in between 
>>>>>>>>>>> it
>>>>>>>>>>> boots with all vcpus network and disk.
>>>>>>>>>>>
>>>>>>>>>>> With grub in between, this at least does look suspicious:
>>>>>>>>>>>
>>>>>>>>>>> [    0.032110] PCI: System does not support PCI
>>>>>>>>>>
>>>>>>>>>> Eh, that's in both, stay awake Hans.
>>>>>>>>>>
>>>>>>>>>>> And yes, there are also no successful netfront lines.
>>>>>>>>>>>
>>>>>>>>>>> Without grub: http://paste.debian.net/plainh/7120cef2
>>>>>>>>>>> With grub: http://paste.debian.net/plainh/426bed60
>>>>>>>>>>
>>>>>>>>>> Or the diff between them, which shows what changes when inserting 
>>>>>>>>>> grub
>>>>>>>>>> in between:
>>>>>>>>>>
>>>>>>>>>> http://paste.debian.net/plainh/52b2d618
>>>>>>>>>>
>>>>>>>>>> I must admit I don't know too much (yet) about all those changed 
>>>>>>>>>> lines,
>>>>>>>>>> but this next is also a very interesting change?...
>>>>>>>>>>
>>>>>>>>>> -Booting paravirtualized kernel on Xen PVH
>>>>>>>>>> +Booting paravirtualized kernel on Xen HVM
>>>>>>>>>
>>>>>>>>> Aah, yes, this should be the reason for the problems.
>>>>>>>>>
>>>>>>>>> I addressed the ACPI problem first. What is missing now is to set PVH
>>>>>>>>> mode when booting via grub.
>>>>>>>>>
>>>>>>>>> So please stay tuned...
>>>>>>>>
>>>>>>>> For my info... Is this something like flipping a bit somewhere, or will
>>>>>>>> it involve a whole lot more complicated wizardry?
>>>>>>>>
>>>>>>>> Real question is of course if there's a PoC solution to apply that I 
>>>>>>>> can
>>>>>>>> use now? ;-] I'm throwing custom build kernels at my test environment,
>>>>>>>> and if I could save the time (and mistakes) of manually editing the
>>>>>>>> guest files and instead hit the pvgrub2+PVHv2 path many times to 
>>>>>>>> test...
>>>>>>>
>>>>>>> So I looked into this briefly and discovered that my memory really needs
>>>>>>> the backup I have on my hard disk: you want commit
>>>>>>> 418492ba40b2c2bbdaf1a169aac5b1673bde8189 which was for 4.15.
>>>>>>
>>>>>> Aha. Well, I can as well better jump to 4.15 now, since picking that
>>>>>> patch on 4.14.17 shows I need more other patches it depends on, related
>>>>>> to struct x86_legacy_features and x86_hyper_init reorganization.
>>>>>>
>>>>>> So, I just built a 4.15.1 kernel (using gcc 7.2.0), which definitely has
>>>>>> this one in it:
>>>>>>   418492ba40b2 x86/virt/xen: Use guest_late_init to detect Xen PVH guest
>>>>>>
>>>>>> I can boot via pvgrub2 (the Xen that's running now is current
>>>>>> stable-4.10 plus the RSDP for PVH guest near 4GB patch).
>>>>>>
>>>>>> But, it still tells me...
>>>>>>   Booting paravirtualized kernel on Xen HVM
>>>>>>
>>>>>> ...and then hangs somewhere halfway.
>>>>>>
>>>>>> Full boot log here: http://paste.debian.net/plainh/ae3ea14b
>>>>>
>>>>> You didn't add the RSDP detection patch, right? In the log I see:
>>>>>
>>>>> ACPI BIOS Error (bug): A valid RSDP was not found (20170831/tbxfroot-244)
>>>>
>>>> Yes, I didn't have those. Argh...
>>>>
>>>> However, after putting the 'xen: re-enable booting as Xen PVH guest' v2
>>>> patches on top, same happens.
>>>
>>> Sure. Those don't take RSDP from boot parameters set by grub2.
>>>
>>> You need to apply the 4 patch series from:
>>>
>>> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/boot
>>>
>>> Commit-Ids are:
>>> 2f74cbf947f45fa082dda8eac1a1f1299a372f49
>>> 0c89cf36424f7c1177de8a5712514d7cc2eb369f
>>> 88750a6c33f813b815516990f01fb5ee488c477e
>>> 930ba49b2ce7b09a5eddc21385fd944ba6b4e829
>>
>> Ah, D'OH. The patch sets currently bite each other. And, for some reason
>> I messed up and was wrongly thinking I already had those in 4.15, since
>> which is entirely not the case. No idea why I thought that.
>>
>> So, since I'm testing pvgrub2, I threw the 'xen: re-enable booting as
>> Xen PVH guest' out again, and applied those 4 again on 4.15.1.
>>
>> Now I at least have this...
>> [    0.000000] Booting paravirtualized kernel on Xen PVH
>> ...and no more 'A valid RSDP was not found'...
>>
>> ...but quite some complaining going on about ACPI, like 'BIOS bug: APIC
>> version mismatch' and 'ACPI BIOS Warning (bug): Incorrect checksum in
>> table' however, and per cpu there's a 10 second boot delay (didn't see
>> that one before yet), and I have only 1 vcpu in the end etc...
>>
>> Full output:
>> http://paste.debian.net/plainh/262cfbcf
> 
> e820: BIOS-provided physical RAM map:
> BIOS-e820: [mem 0x0000000000000000-0x00000000fbffffff] usable
> BIOS-e820: [mem 0x00000000fc000000-0x00000000fc000fff] ACPI data
> BIOS-e820: [mem 0x00000000fc001000-0x00000000fc008fff] usable
> BIOS-e820: [mem 0x00000000fc009000-0x00000000fc009fff] ACPI data
> BIOS-e820: [mem 0x00000000fc00a000-0x00000000fedfffff] usable
> 
> and
> 
> ACPI: Early table checksum verification disabled
> ACPI: RSDP 0x00000000FC009000 000024 (v02 Xen   )
> ACPI: XSDT 0x00000000FC007FB0 000034 (v01 Xen HVM 00000000 HVML 00000000)
> ACPI: FACP 0x00000000FC007D70 00010C (v05 Xen HVM 00000000 HVML 00000000)
> ACPI: DSDT 0x00000000FC001050 000003 (v164 �mn FE942AD6 ?    FC001510)
> ACPI:      0x00000000FC001010 000001 (v08 <-   6DB08FA4      62757267)
> ACPI:      0x00000000FC001010 000001 (v08 <-   6DB08FA4      62757267)
> ACPI: APIC 0x00000000FC007E80 00007C (v02 Xen HVM 00000000 HVML 00000000)
> 
> Seems as if some ACPI data areas are missing in the E820 map.
> 
> Can you try configuring the guest with e.g. 3GB memory instead of 4GB?

Instead of 100 GiB you mean? :]

type="pvh"
kernel = "/yolo/grub-i386-xenpvh-fire-ze-missile"
memory = 102400
vcpus = 10

When I change that to...

memory = 3072
vcpus = 4

...I get this:

http://paste.debian.net/plainh/f8676322

Hans

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