[Query] How does Xen X86 does pci enumeration

[Query] How does Xen X86 does pci enumeration

[Xenbegn developer]

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Hi,

Small beginner query. Where in Xen X86 code pci ep enumeration is done?
I believe it this should be the flow of events
a)  from ACPI enumerate all the PCI controllers
b) On each Controller start enumerating the pci devices.

I started from _start_xen in arch/x86/setup.c but couldnt find the top
level function.
Can anyone please provide pointer.

Thanks

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_______________________________________________
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Re: [Query] How does Xen X86 does pci enumeration

[Konrad Rzeszutek Wilk]

On Tue, Jul 15, 2014 at 11:54:34AM +0530, Xenbegn developer wrote:
> Hi,
> 
> Small beginner query. Where in Xen X86 code pci ep enumeration is done?
> I believe it this should be the flow of events
> a)  from ACPI enumerate all the PCI controllers
> b) On each Controller start enumerating the pci devices.

No. You can also query the PCI via the configuration registers.

Look in the 'pci.c' files.
> 
> I started from _start_xen in arch/x86/setup.c but couldnt find the top
> level function.
> Can anyone please provide pointer.
> 
> Thanks

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel

Re: [Query] How does Xen X86 does pci enumeration

[Xenbegn developer]

On 7/15/14, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> On Tue, Jul 15, 2014 at 11:54:34AM +0530, Xenbegn developer wrote:
>> Hi,
>>
>> Small beginner query. Where in Xen X86 code pci ep enumeration is done?
>> I believe it this should be the flow of events
>> a)  from ACPI enumerate all the PCI controllers
>> b) On each Controller start enumerating the pci devices.
>
> No. You can also query the PCI via the configuration registers.
>
> Look in the 'pci.c' files.
>>
>> I started from _start_xen in arch/x86/setup.c but couldnt find the top
>> level function.
>> Can anyone please provide pointer.
>>
One supplement question, does Xen do PCI devices enumeration or Dom0 does it ?


>> Thanks
>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@lists.xen.org
>> http://lists.xen.org/xen-devel
>
>

Re: [Query] How does Xen X86 does pci enumeration

[Konrad Rzeszutek Wilk]

On Wed, Jul 16, 2014 at 05:25:07PM +0530, Xenbegn developer wrote:
> On 7/15/14, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > On Tue, Jul 15, 2014 at 11:54:34AM +0530, Xenbegn developer wrote:
> >> Hi,
> >>
> >> Small beginner query. Where in Xen X86 code pci ep enumeration is done?
> >> I believe it this should be the flow of events
> >> a)  from ACPI enumerate all the PCI controllers
> >> b) On each Controller start enumerating the pci devices.
> >
> > No. You can also query the PCI via the configuration registers.
> >
> > Look in the 'pci.c' files.
> >>
> >> I started from _start_xen in arch/x86/setup.c but couldnt find the top
> >> level function.
> >> Can anyone please provide pointer.
> >>
> One supplement question, does Xen do PCI devices enumeration or Dom0 does it ?

Both.
> 
> 
> >> Thanks
> >
> >> _______________________________________________
> >> Xen-devel mailing list
> >> Xen-devel@lists.xen.org
> >> http://lists.xen.org/xen-devel
> >
> >

Re: [Query] How does Xen X86 does pci enumeration

[Xenbegn developer]

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On Wed, Jul 16, 2014 at 7:19 PM, Konrad Rzeszutek Wilk <
konrad.wilk@oracle.com> wrote:

> On Wed, Jul 16, 2014 at 05:25:07PM +0530, Xenbegn developer wrote:
> > On 7/15/14, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > > On Tue, Jul 15, 2014 at 11:54:34AM +0530, Xenbegn developer wrote:
> > >> Hi,
> > >>
> > >> Small beginner query. Where in Xen X86 code pci ep enumeration is
> done?
> > >> I believe it this should be the flow of events
> > >> a)  from ACPI enumerate all the PCI controllers
> > >> b) On each Controller start enumerating the pci devices.
> > >
> > > No. You can also query the PCI via the configuration registers.
> > >
> > > Look in the 'pci.c' files.
> > >>
> > >> I started from _start_xen in arch/x86/setup.c but couldnt find the top
> > >> level function.
> > >> Can anyone please provide pointer.
> > >>
> > One supplement question, does Xen do PCI devices enumeration or Dom0
> does it ?
>
> Both.
>

What is the use case for dom0 and xen both to do pci devices enumeration.
What purpose it solves for xen ?


> >
> >
> > >> Thanks
> > >
> > >> _______________________________________________
> > >> Xen-devel mailing list
> > >> Xen-devel@lists.xen.org
> > >> http://lists.xen.org/xen-devel
> > >
> > >
>

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_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel

Re: [Query] How does Xen X86 does pci enumeration

[Konrad Rzeszutek Wilk]

On Tue, Jul 22, 2014 at 03:21:31PM +0530, Xenbegn developer wrote:
> On Wed, Jul 16, 2014 at 7:19 PM, Konrad Rzeszutek Wilk <
> konrad.wilk@oracle.com> wrote:
> 
> > On Wed, Jul 16, 2014 at 05:25:07PM +0530, Xenbegn developer wrote:
> > > On 7/15/14, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> > > > On Tue, Jul 15, 2014 at 11:54:34AM +0530, Xenbegn developer wrote:
> > > >> Hi,
> > > >>
> > > >> Small beginner query. Where in Xen X86 code pci ep enumeration is
> > done?
> > > >> I believe it this should be the flow of events
> > > >> a)  from ACPI enumerate all the PCI controllers
> > > >> b) On each Controller start enumerating the pci devices.
> > > >
> > > > No. You can also query the PCI via the configuration registers.
> > > >
> > > > Look in the 'pci.c' files.
> > > >>
> > > >> I started from _start_xen in arch/x86/setup.c but couldnt find the top
> > > >> level function.
> > > >> Can anyone please provide pointer.
> > > >>
> > > One supplement question, does Xen do PCI devices enumeration or Dom0
> > does it ?
> >
> > Both.
> >
> 
> What is the use case for dom0 and xen both to do pci devices enumeration.
> What purpose it solves for xen ?

To figure out which PCI interrupts should be assigned to the guest and also
do the MSI and MSI-X writes to the BAR space of PCI devices - instead of
the guest doing it.