Re: [Xen-devel] [PATCH] Register PV driver product numbers 4 and 5.

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Wednesday, October 9, 2013, 12:19:38 PM, you wrote:

>> -----Original Message-----
>> From: Sander Eikelenboom [mailto:linux@xxxxxxxxxxxxxx]
>> Sent: 09 October 2013 10:10
>> To: Ian Campbell
>> Cc: Paul Durrant; xen-devel@xxxxxxxxxxxxx
>> Subject: Re: [Xen-devel] [PATCH] Register PV driver product numbers 4 and
>> 5.
>> 
>> 
>> Wednesday, October 9, 2013, 10:00:53 AM, you wrote:
>> 
>> > On Tue, 2013-10-08 at 15:53 +0100, Paul Durrant wrote:
>> 
>> >> > It's a bit confusing, I agree. Referring back to previous threads 
>> >> > though,
>> all
>> >> > HVM systems are assumed to have the xen platform PCI device (as
>> there is
>> >> > no way to turn it off if youâre using machine type xenfv), thus the 
>> >> > fixed
>> IO
>> >> > ports that implement the blacklisting protocol are assumed to always be
>> >> > present. Because the ports are fixed and always present the PV drivers
>> don't
>> >> > have to care which device they are binding to - they talk to the same IO
>> ports
>> >> > regardless.
>> 
>> Paul,
>> 
>> Do you by any chance know the commit that made this unconditional ?
>> (it used to be possible to switch it off with xen_platform_pci=0, and i'm 
>> trying
>> to see
>> if the platform device and the hidden NIC (pci 00:03.0 not visible in guest 
>> lspci
>> but it's there
>> (xl dmesg reports it begin generate and there is a gap in the device number
>> (platform 00:02.0 passthroughed device 00:04.0) has something to do with it.
>>

> Sander,

>   It wasn't a commit that did this as such, it's just that no-one added the 
> option to turn it off in upstream QEMU. I believe you can still turn it off 
> if you're using trad QEMU.

Hrmmm it seems the unplug of disk and nic is also unconditional then ?
Regardless if the guest os has the PV drivers ?

(using a recent guest kernel without xen pv drivers can't find it's disk and 
thus boot device ?)

>  
>> The rom bar of my passthroughed device some how gets wired at first to the
>> vga bios of the cirrus vga or stdvga.
>> When i disable the emulated vga (-nographic and -vga none) it is suddenly
>> wired to the ixpe rom (of device 00:03.0).
>> 
>> So there is something funky going on in either hvmloader, seabios and/or
>> qemu.

> Yes, that sounds very funky.

Yips, any reason why the PV nic is unvisible for lspci ?

>   Paul

>> But it would be nice to rule out as much as possible.
>> 
>> --
>> Sander
>> 
>> > That makes sense I suppose.
>> 
>> > Can we add some words about this relationship to the docs then?
>> 
>> >> Ping? Do I need to add any further clarification?
>> 
>> > I thought I'd already replied but I don't see it anywhere on the list or
>> > in my sent box, sorry.
>> 
>> > Ian/
>> 
>> 
>> 



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