RE: [PATCH 04/12] platform/x86: dell-smbios: Switch to a WMI-ACPI interface

From: Mario.Limonciello
Date: Wed Sep 27 2017 - 14:29:28 EST


> -----Original Message-----
> From: Darren Hart [mailto:dvhart@xxxxxxxxxxxxx]
> Sent: Wednesday, September 27, 2017 12:46 PM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> Cc: pali.rohar@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; platform-driver-
> x86@xxxxxxxxxxxxxxx; quasisec@xxxxxxxxxx
> Subject: Re: [PATCH 04/12] platform/x86: dell-smbios: Switch to a WMI-ACPI
> interface
>
> On Mon, Sep 25, 2017 at 07:28:57PM +0000, Mario.Limonciello@xxxxxxxx wrote:
> >
> >
> > > -----Original Message-----
> > > From: Pali Rohár [mailto:pali.rohar@xxxxxxxxx]
> > > Sent: Monday, September 25, 2017 12:19 PM
> > > To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> > > Cc: dvhart@xxxxxxxxxxxxx; LKML <linux-kernel@xxxxxxxxxxxxxxx>; platform-
> driver-
> > > x86@xxxxxxxxxxxxxxx; quasisec@xxxxxxxxxx
> > > Subject: Re: [PATCH 04/12] platform/x86: dell-smbios: Switch to a WMI-ACPI
> > > interface
> > >
> > > On Thursday 21 September 2017 08:57:09 Mario Limonciello wrote:
> > > > The driver currently uses an SMI interface which grants direct access
> > > > to physical memory to the platform via a pointer.
> > > >
> > > > Changing this to operate over WMI-ACPI will use an ACPI OperationRegion
> > > > for a buffer of data storage when platform calls are performed.
> > > >
> > > > This is a safer approach to use in kernel drivers as the platform will
> > > > only have access to that OperationRegion.
> > >
> > > In my opinion direct access is safer then using ACPI wrapper for same
> > > functionality.
> >
> > I'd like to hear how this is safer.
>
> Again, I think the disconnect is around the term "platform". I think above you
> can s/platform/SMM/ right?
>

>From my OEM hat we don't really refer to SMM as an entity, but "Yeah" if that
makes it clearer I'd agree.