Re: [Xen-devel] linux-3.9-rc0 regression from 3.8 SATA controller not detected under xen

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, Feb 27, 2013 at 06:50:59PM +0100, Sander Eikelenboom wrote:
> 
> Wednesday, February 27, 2013, 1:54:31 PM, you wrote:
> 
> >>>> On 27.02.13 at 12:46, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
> >>   [   89.338827] ahci: probe of 0000:00:11.0 failed with error -22
> 
> > Which is -EINVAL. With nothing else printed, I'm afraid you need to
> > find the origin of this return value by instrumenting the involved
> > call tree.
> 
> Just wondering, is multiple msi's per device actually supported by xen ?

That is very good question. I know we support MSI-X b/c 1GB or 10GB NICs
use them and they work great with Xen.

BTW, this is merge:
ommit 5800700f66678ea5c85e7d62b138416070bf7f60
Merge: 266d7ad af8d102
Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date:   Tue Feb 19 19:07:27 2013 -0800

    Merge branch 'x86-apic-for-linus' of 
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
    
    Pull x86/apic changes from Ingo Molnar:
     "Main changes:
    
       - Multiple MSI support added to the APIC, PCI and AHCI code - acked
         by all relevant maintainers, by Alexander Gordeev.
    
         The advantage is that multiple AHCI ports can have multiple MSI
         irqs assigned, and can thus spread to multiple CPUs.
    
         [ Drivers can make use of this new facility via the
           pci_enable_msi_block_auto() method ]



With MSI per device, the hypercall that ends up happening is:
PHYSDEVOP_map_pirq with:

   map_irq.domid = domid;
   map_irq.type = MAP_PIRQ_TYPE_MSI_SEG;
   map_irq.index = -1;
   map_irq.pirq = -1;
   map_irq.bus = dev->bus->number |
                 (pci_domain_nr(dev->bus) << 16);
   map_irq.devfn = dev->devfn;

Which would imply that we are doing this call multiple times?
(This is xen_initdom_setup_msi_irqs).

It looks like pci_enable_msi_block_auto is the multiple MSI one
and it should perculate down to xen_initdom_setup_msi_irqs.
Granted the xen_init.. does not do anything with the 'nvec' call.

So could I ask you try out your hunch by doing three things:
 1). Instrument xen_initdom_setup_msi_irqs to see if the
     nvec has anything but 1 and in its loop instrument to
     see if it has more than on MSI attribute?

 2). The ahci driver has ahci_init_interrupts which only does
   the multiple MSI thing if AHCI_HFLAG_NO_MSI is not set.
    If you edit drivers/ata/ahci ahci_port_info for the SB600 (or 700?)
    to have AHCI_HFLAG_NO_MSI flag (you probably want to do this
    seperatly from 1).
 3). Checkout before merge 5800700f66678ea5c85e7d62b138416070bf7f60
    and try 266d7ad7f4fe2f44b91561f5b812115c1b3018ab? 
> 
> --
> Sander
> 
> > Jan
> 
> 
> 
> 
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> 

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