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From:   Rajat Jain <rajatja@google.com>
Date:   Mon, 22 Jun 2020 16:01:34 -0700
Message-ID: <CACK8Z6FZ560vfMYH8idaea31_9dq4Vvo7LiMASnxZKZJtX89wg@mail.gmail.com>
Subject: Re: [PATCH 3/4] pci: acs: Enable PCI_ACS_TB for untrusted/external-facing
 devices
To:     "Raj, Ashok" <ashok.raj@intel.com>
Cc:     David Woodhouse <dwmw2@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>, iommu@lists.linux-foundation.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-pci <linux-pci@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        "Krishnakumar, Lalithambika" <lalithambika.krishnakumar@intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Prashant Malani <pmalani@google.com>,
        Benson Leung <bleung@google.com>,
        Todd Broch <tbroch@google.com>,
        Alex Levin <levinale@google.com>,
        Mattias Nissler <mnissler@google.com>,
        Rajat Jain <rajatxjain@gmail.com>,
        Bernie Keany <bernie.keany@intel.com>,
        Aaron Durbin <adurbin@google.com>,
        Diego Rivas <diegorivas@google.com>,
        Duncan Laurie <dlaurie@google.com>,
        Furquan Shaikh <furquan@google.com>,
        Jesse Barnes <jsbarnes@google.com>,
        Christian Kellner <christian@kellner.me>,
        Alex Williamson <alex.williamson@redhat.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Oliver O'Halloran" <oohall@gmail.com>
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Hi Ashok,

On Fri, Jun 19, 2020 at 9:10 AM Raj, Ashok <ashok.raj@intel.com> wrote:
>
> Hi Rajat
>
>
> On Mon, Jun 15, 2020 at 06:17:41PM -0700, Rajat Jain wrote:
> > When enabling ACS, currently the bit "translation blocking" was
> > not getting changed at all. Set it to disable translation blocking
>
> Maybe you meant "enable translation blocking" ?

Oops, yes.

>
> Keep the commit log simple:
>
> When enabling ACS, enable translation blocking for external facing ports
> and untrusted devices.

Ack. Will change in the next iteration (currently waiting to see if
there are any more comments).

Thanks & Regards,

Rajat

>
> > too for all external facing or untrusted devices. This is OK
> > because ATS is only allowed on internal devces.
> >
> > Signed-off-by: Rajat Jain <rajatja@google.com>
> > ---
> >  drivers/pci/pci.c    |  4 ++++
> >  drivers/pci/quirks.c | 11 +++++++++++
> >  2 files changed, 15 insertions(+)
> >
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index d2ff987585855..79853b52658a2 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -3330,6 +3330,10 @@ static void pci_std_enable_acs(struct pci_dev *dev)
> >       /* Upstream Forwarding */
> >       ctrl |= (cap & PCI_ACS_UF);
> >
> > +     if (dev->external_facing || dev->untrusted)
> > +             /* Translation Blocking */
> > +             ctrl |= (cap & PCI_ACS_TB);
> > +
> >       pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl);
> >  }
> >
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index b341628e47527..6294adeac4049 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -4934,6 +4934,13 @@ static void pci_quirk_enable_intel_rp_mpc_acs(struct pci_dev *dev)
> >       }
> >  }
> >
> > +/*
> > + * Currently this quirk does the equivalent of
> > + * PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_SV
> > + *
> > + * Currently missing, it also needs to do equivalent of PCI_ACS_TB,
> > + * if dev->external_facing || dev->untrusted
> > + */
> >  static int pci_quirk_enable_intel_pch_acs(struct pci_dev *dev)
> >  {
> >       if (!pci_quirk_intel_pch_acs_match(dev))
> > @@ -4973,6 +4980,10 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev)
> >       ctrl |= (cap & PCI_ACS_CR);
> >       ctrl |= (cap & PCI_ACS_UF);
> >
> > +     if (dev->external_facing || dev->untrusted)
> > +             /* Translation Blocking */
> > +             ctrl |= (cap & PCI_ACS_TB);
> > +
> >       pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl);
> >
> >       pci_info(dev, "Intel SPT PCH root port ACS workaround enabled\n");
> > --
> > 2.27.0.290.gba653c62da-goog
> >