Re: Keystone Issue

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Mon, 15 Jun 2020, CodeWiz2280 wrote:
> On Wed, Jun 10, 2020 at 5:46 PM Julien Grall <julien.grall.oss@xxxxxxxxx> 
> wrote:
> >
> > Hi Marc,
> >
> > On Tue, 9 Jun 2020 at 18:45, Marc Zyngier <maz@xxxxxxxxxx> wrote:
> > > > I was wondering if you heard about any potential issue with guest EOI
> > > > not forwarded to the host. This is on TI Keystone (Cortex A-15).
> > >
> > > Not that I know of. A-15 definitely works (TC2, Tegra-K1, Calxeda Midway
> > > all run just fine with guest EOI), and GIC-400 is a pretty solid piece
> > > of kit (it is just sloooooow...).
> > >
> > > Thinking of it, you would see something like that if the GIC was seeing
> > > the writes coming from the guest as secure instead of NS (cue the early
> > > firmware on XGene that exposed the wrong side of GIC-400).
> >
> > Ah, I remember that one.  We used to carry an hack in Xen [1] for
> > X-Gene. Thankfully they fixed the firmware!
> >
> > If it is a similar issue, then the firmware path would definitely be
> > my preference.
> >
> > Thank you for the input!
> 
> Thank you all for the information.  If I pull the changes to use the
> maintenance interrupt for the X-Gene back into the latest build of Xen
> then my issue with the Edge and Level interrupts is resolved.  My
> ethernet and other devices work fine again for the Keystone in dom0.
> Are there any concerns over operating this way, meaning with the
> maintenance interrupt workaround rather than the EOI?  Is this safe?

It should be fine, a small impact on performance, that's all.


> Also, the latest linux kernel still has the X-Gene storm distributor
> address as "0x78010000" in the device tree, which is what the Xen code
> considers a match with the old firmware.  What were the addresses for
> the device tree supposed to be changed to?  Is my understanding
> correct that there is a different base address required to access the
> "non-secure" region instead of the "secure" 0x78010000 region?  I'm
> trying to see if there are corresponding different addresses for the
> keystone K2E, but haven't found them yet in the manuals.

I went through the old emails archive but couldn't find a mention of the
other address, sorry.