Re: [PATCH v5 04/10] hw/intc: GICv3 ITS Command processing

[shashi . mallela]

On Tue, 2021-07-06 at 14:27 +0100, Peter Maydell wrote:
> On Tue, 6 Jul 2021 at 13:46, <shashi.mallela@linaro.org> wrote:
> > On Tue, 2021-07-06 at 10:19 +0100, Peter Maydell wrote:
> > > On Tue, 6 Jul 2021 at 04:25, <shashi.mallela@linaro.org> wrote:
> > > 
> > > But the pseudocode for MAPTI does not say anywhere that we should
> > > be checking the pIntID against any CPU's GICR_PROPBASER field.
> > > It is checked only by the checks in LPIOutOfRange(), which tests:
> > >  * is it larger than permitted by GICD_TYPER.IDbits
> > >  * is it not in the LPI range and not 1023
> > > 
> > > Checking whether the intID is too big and would cause us to index
> > > off the end of the redistributor's configuration table should be
> > > done
> > > later, only when the ITS actually sends the interrupt to a
> > > particular
> > > redistributor, I think.
> > > 
> > > (You can't rely on the guest having done the MAPC before the
> > > MAPTI;
> > > and in any case the guest could choose to do a MAPC to a
> > > different
> > > redistributor after it's done the MAPTI.)
> > We already have the "intID too big check" in place within the
> > redistributor processing when ITS sends the interrupt trigger.
> > "the LPI range and not 1023" is also handled in this function,but
> > for
> > validating "is it larger than permitted by GICD_TYPER.IDbits",the
> > source of GICD_TYPER.IDbits is GICR_PROPBASER because we pick up
> > min of
> > GICR_PROPBASER.IDbits and GICD_TYPER.IDBits.
> > 
> > If we are to not use gicr_propbaser,then are we good to just accept
> > the
> > intID value here since we are validating the same during interrupt
> > processing?
> 
> You should check the things the pseudocode says you should check.
> When processing MAPTI, that's GICD_TYPER.IDbits.
> GICR_PROPBASER.IDbits
> is not the same thing because the guest can set it to a smaller
> value.
Have made changes in code to check "intID too big" case using
GICD_TYPER.IDbits instead of GICR_PROPBASER.IDbits
> thanks
> -- PMM