Re: [PATCH v2 2/8] ArmPkg: PCD to select conduit for monitor calls

["Ard Biesheuvel" <ardb@kernel.org>]

On Wed, 24 Nov 2021 at 13:07, Leif Lindholm <leif@nuviainc.com> wrote:
>
> Ard - how does this interact with e.g. ArmVirtPsciResetSystemLib,
> which reads its conduit out of the DT passed to it by QEMU?
>

As long as ArmCallSmc() and ArmCallHvc() continue to exist and behave
as before, I don't think those libraries are affected.

>
> On Tue, Nov 16, 2021 at 11:32:54 +0000, Sami Mujawar wrote:
> > Bugzilla: 3668 (https://bugzilla.tianocore.org/show_bug.cgi?id=3668)
> >
> > Define a PCD 'PcdMonitorConduitHvc' to select the conduit to use for
> > monitor calls. PcdMonitorConduitHvc is defined as FALSE by default,
> > meaning the SMC conduit is enabled as default.
> >
> > Adding PcdMonitorConduitHvc allows selection of HVC conduit to be used
> > by virtual firmware implementations.
> >
> > Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
> > ---
> >
> > Notes:
> >     v2:
> >      - No code change since v1. Re-sending with V2 series.   [SAMI]
> >
> >  ArmPkg/ArmPkg.dec | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/ArmPkg/ArmPkg.dec b/ArmPkg/ArmPkg.dec
> > index 9da1bbc9f2166dc8ae93f96a34d3165fffed34dc..9a53888ae52f00eec50e631cf1bfcacecf8bba87 100644
> > --- a/ArmPkg/ArmPkg.dec
> > +++ b/ArmPkg/ArmPkg.dec
> > @@ -132,6 +132,11 @@ [PcdsFeatureFlag.common]
> >    # Define if the GICv3 controller should use the GICv2 legacy
> >    gArmTokenSpaceGuid.PcdArmGicV3WithV2Legacy|FALSE|BOOLEAN|0x00000042
> >
> > +  ## Define the conduit to use for monitor calls.
> > +  # Default PcdMonitorConduitHvc = FALSE, conduit = SMC
> > +  # If PcdMonitorConduitHvc = TRUE, conduit = HVC
> > +  gArmTokenSpaceGuid.PcdMonitorConduitHvc|FALSE|BOOLEAN|0x00000047
> > +
> >  [PcdsFeatureFlag.ARM]
> >    # Whether to map normal memory as non-shareable. FALSE is the safe choice, but
> >    # TRUE may be appropriate to fix performance problems if you don't care about
> > --
> > 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
> >