Re: Xenbus issues on Qubes OS / win10

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Jun 27, 2023 at 11:37:54AM +0100, Paul Durrant wrote:
> On 23/06/2023 19:50, Rafał Wojdyła wrote:
> > On 23 cze 2023 17:37, Rafał Wojdyła wrote:
> > > Hello,
> > > 
> > > I'm trying the latest PV drivers on Qubes OS (backend is Xen 4.14.5)
> > > with Windows 10 pro and having some issues. Mainly, xenbus fails to
> > > initialize properly. I've attached a debug output, the main issue
> > > seems to be this:
> > > 
> > > xenbus|StoreAcquire: ====>
> > > xenbus|GnttabAcquire: ====>
> > > xenbus|RangeSetPop: fail3
> > > xenbus|RangeSetPop: fail2
> > > xenbus|RangeSetPop: fail1 (c000009a)
> > > xenbus|FdoAllocateHole: fail1 (c000009a)
> > > xenbus|GnttabAcquire: fail2
> > > xenbus|GnttabAcquire: fail1 (c000009a)
> > > xenbus|StoreAcquire: fail1 (c000009a)
> > > xenbus|FdoD3ToD0: fail6
> > > 
> > > ...which seems pretty suspicious. It's been some years since I
> > > looked at the drivers' code so any ideas as to what may be causing
> > > this are welcome :)
> > > 
> > Followup: in xenbus/gnttab/GnttabAcquire()
> > 
> > status = GrantTableQuerySize(NULL, &Context->MaximumFrameCount);
> > 
> > Context->MaximumFrameCount is 2048 for me, which is bigger than 1 <<
> > PAGE_ORDER_2M, which seems to be the limit for FDO memory hole size.
> > 
> 
> Hmm. Ok - we should probably put something in there to either expand the
> hole, use another one or - probably simpler - query the grant table size
> up-front to correctly size the hole.

For context - in Qubes we indeed raise the max grant table frames to the
value Rafał got.

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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