Re: xl pci-attach silently fails the first time

[Sander Eikelenboom <linux@eikelenboom.it>]

Monday, December 1, 2014, 2:42:11 PM, you wrote:

> On Mon, Dec 01, Olaf Hering wrote:

>> > # xl pci-attach domU 0000:01:10.0

> "xl pci-attach -h" mentions [Virtual Slot], but the code does not seem
> to handle an additional parameter, pciattach() ignores *vs.

> What is the "Virtual Slot", why is it ignored?

Hmm the wiki also still mentions it: http://wiki.xen.org/wiki/Xen_PCI_Passthrough

It was the ability with xend + qemu-trad to be able to specify the slot to 
use in the guest for the pci device.

See docs/misc/vtd.txt .. that seems it has never been updated :-)

(together with passing through a multifunction devices as multifunction inside 
the guest this hasn't got implemented in neither libxl and qemu-xen.)

--
Sander

>From docs/misc/vtd.txt: 

VTd device hotplug:
-------------------

2 virtual PCI slots (6~7) are reserved in HVM guest to support VTd hotplug. If you have more VTd devices, only 2 of them can support hotplug. Usage is simple:

 1. List the VTd device by dom. You can see a VTd device 0:2:0.0 is inserted in the HVM domain's PCI slot 6. '''lspci''' inside the guest should see the same.

        [root@vt-vtd ~]# xm pci-list HVMDomainVtd
        VSlt domain   bus   slot   func
        0x6    0x0  0x02   0x00    0x0

 2. Detach the device from the guest by the physical BDF. Then HVM guest will receive a virtual PCI hot removal event to detach the physical device

        [root@vt-vtd ~]# xm pci-detach HVMDomainVtd 0:2:0.0

 3. Attach a PCI device to the guest by the physical BDF and desired virtual slot(optional). Following command would insert the physical device into guest's virtual slot 7

        [root@vt-vtd ~]# xm pci-attach HVMDomainVtd 0:2:0.0 7

    To specify options for the device, use -o or --options=. Following command would disable MSI-INTx translation for the device

        [root@vt-vtd ~]# xm pci-attach -o msitranslate=0 0:2:0.0 7






> Olaf