From: "Ard Biesheuvel" <ardb@kernel.org>
To: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: devel@edk2.groups.io, jeremy.linton@arm.com, abner.chang@amd.com
Subject: Re: [edk2-devel] [PATCH 1/1] EmbeddedPkg/NonCoherentIoMmuDxe: Make SetAttributes always succeed
Date: Tue, 12 Mar 2024 17:58:44 +0100 [thread overview]
Message-ID: <CAMj1kXHZc+Zxy2HeLoKTjTSSqDoc6kNxwsS19W5m+2hAF2RfFw@mail.gmail.com> (raw)
In-Reply-To: <f446f9ef-84da-4d87-bdaf-928f489fbff1@quicinc.com>
On Tue, 12 Mar 2024 at 17:56, Leif Lindholm <quic_llindhol@quicinc.com> wrote:
>
> On 2024-03-12 09:50, Ard Biesheuvel wrote:
> > On Tue, 12 Mar 2024 at 17:38, Leif Lindholm <quic_llindhol@quicinc.com> wrote:
> >>
> >> On 2024-03-12 08:17, Ard Biesheuvel wrote:
> >>> From: Ard Biesheuvel <ardb@kernel.org>
> >>>
> >>> NonCoherentIoMmuSetAttribute() does nothing except return
> >>> EFI_UNSUPPORTED. This was fine when it was introduced, but now, the PCI
> >>> bus driver will fail a PCI I/O Map() operation if the SetAttributes
> >>> fails.
> >>>
> >>> So return EFI_SUCCESS instead.
> >>
> >> It's unclear to me why this change is safe (looking forward).
> >> Does NonCoherentIoMmuDxe also imply no IoMmu actually exists?
> >>
> >
> > Basically. NonCoherentIoMmuDxe is just a vehicle to allow
> > NonCoherentDmaLib to be plugged into the PCI host bridge driver. It is
> > not intended to ever do anything more than that.
>
> Not that it needs to happen for this
> (Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>)
> but maybe we ought to consider renaming it then?
> DummyIoMmuDxe?
>
Fair point. Or PassThroughIoMmuDxe perhaps?
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next prev parent reply other threads:[~2024-03-12 16:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 15:17 [edk2-devel] [PATCH 1/1] EmbeddedPkg/NonCoherentIoMmuDxe: Make SetAttributes always succeed Ard Biesheuvel via groups.io
2024-03-12 16:38 ` Leif Lindholm
2024-03-12 16:50 ` Ard Biesheuvel
2024-03-12 16:56 ` Leif Lindholm
2024-03-12 16:58 ` Ard Biesheuvel [this message]
2024-03-12 17:14 ` Leif Lindholm
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