Re: [Xen-devel] Notes from PCI Passthrough design discussion at Xen Summit

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 20/07/17 10:32, Manish Jaggi wrote:
> Hi Roger,
>
> On 7/20/2017 1:54 PM, Roger Pau Monné wrote:
> > On Thu, Jul 20, 2017 at 09:24:36AM +0530, Manish Jaggi wrote:
> > > Hi Punit,
> > >
> > > On 7/19/2017 8:11 PM, Punit Agrawal wrote:
> > > > I took some notes for the PCI Passthrough design discussion at Xen
> > > > Summit. Due to the wide range of topics covered, the notes got sparser
> > > > towards the end of the session. I've tried to attribute names against
> > > > comments but have very likely got things mixed up. Apologies in
> > > > advance.
> > > Was curious if any discussions happened on the RC Emu (config space
> > > emulation) as per slide 18
> > > https://schd.ws/hosted_files/xendeveloperanddesignsummit2017/76/slides.pdf
> > Part of this is already posted on the list (ATM for x86 only) but the
> > PCI specification (and therefore the config space emulation) is not
> > tied to any arch:
> >
> > https://lists.xenproject.org/archives/html/xen-devel/2017-06/msg03698.html
> From the summary, I have a  questions on
> "
>  - Roger: Registering config space with Xen before device discovery
>   will allow the hypervisor to set access traps for certain
>  functionality as appropriate"
>
> Traps will do emulation or something else ?
>  Is the config space emulation only for DomU or it for Dom0 as well ?
> Slide 18 shows only for DomU ?
My slides are not meant to be read without the talk. In this particular 
case, this is only explaining how passthrough will work for DomU.
Roger series is at the moment focusing on emulating a fully ECAM 
compliant hostbridge for the hardware domain. This is because Xen and 
the hardware domain should not access the configuration space at the 
same time. We may also perform some tasks (i.e MSI mapping, memory 
mapping) or sanitizing when the configuration space is updated by the 
hardware domain.
Cheers,

--
Julien Grall

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