Re: Consuming PCI device in PV kernel

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Jul 15, 2014 at 09:37:56AM +0100, Simon Martin wrote:
> Hello Dario,
> 
> > BTW, how's this going (if I can ask)? Any exciting news about this you
> > can share with the community? :-)
> 
> Nothing   exciting   I'm   afraid,   just   lots  of  donkey work. The
> micropv  project (similar to the Xen mini-os but a LOT lighter with no
> dynamic   memory,   paging  etc)  is  coming  along  nicely.  Lots  of
> improvements   about   talking   to   the  hypervisor and xenstore and
> making  it  more implementation agnostic. The mirage-os guys seemed to
> be interested in this when I first mentioned it. No idea if they still
> are, it's been a while. Too many projects, too little time ;-)
> 
> My  PV  OS  is  sitting  quite  nicely in the hypervisor and I have my
> context  switch  running  nicely  within  the  micropv.  One problem I
> haven't  been  able  to  work  around  so  far is implementing lazy FP
> context recovery, I do it on every context switch. This is crazy but I
> get  FP  exceptions if I don't. As I have larger fish to fry, this one
> is just flagged as something to come back to.
> 
> I had to modify one of the existing Linux kernel drivers (gntalloc) to
> provide  more  functionality.  I  got  it  to  a state in which it was
> accepted  by  Daniel De Graaf the original implementor. I now have to
> push it upstream the Linux kernel maintainers.

Please CC xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com,
david.vrabel@citrix.com, and me when you get a chance to post it.

Please do also run it first through scripts/checkpatch.pl
> 
> As  a  general  comment  I find that the existing Xen documentation is
> fine  for handling existing HVM/PV domain implementations, but you are
> on  your  own  when it comes to implementing your own PV. If it wasn't
> for  the  good  will  of the people on this mailing list I would never
> have  been  able  to  get  where I am now. I know that I am in a small
> niche  here,  and the existing documentation is fine for 99% of people
> who are using Xen. If this is something that should be documented then
> I  would  be  willing  to  have  a  stab at writing some wiki pages if
> someone can clean up the things that I have misunderstood.

Would you be interested in expanding this Wiki a bit:

http://wiki.xen.org/wiki/X86_Paravirtualised_Memory_Management

or correcting it?
?
> 
> Regards, and once again, a big thanks to everyone

Thank you for working on it and I am looking forward to your patches!
<cue evil maniacal laughter> Fresh patches! :-)
> 
> -- 
> Best regards,
>  Simon                            mailto:furryfuttock@gmail.com
>