[PATCH v3 4/4] PCI/ACS: Enable PCI_ACS_TB for untrusted/external-facing devices

[Rajat Jain]

When enabling ACS, enable translation blocking for external facing ports
and untrusted devices.

Signed-off-by: Rajat Jain <rajatja@xxxxxxxxxx>
---
v3: print warning if ACS_TB not supported on external-facing/untrusted ports.
    Minor code comments fixes.
v2: Commit log change

 drivers/pci/pci.c    |  7 +++++++
 drivers/pci/quirks.c | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 73a8627822140..497ac05bf36e8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -876,6 +876,13 @@ static void pci_std_enable_acs(struct pci_dev *dev)
 	/* Upstream Forwarding */
 	ctrl |= (cap & PCI_ACS_UF);
 
+	/* Enable Translation Blocking for external devices */
+	if (dev->external_facing || dev->untrusted)
+		if (cap & PCI_ACS_TB)
+			ctrl |= PCI_ACS_TB;
+		else
+			pci_warn(dev, "ACS: No Trans Blocking on ext dev\n");
+
 	pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl);
 }
 
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index b341628e47527..9cc8c1dc215ee 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_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF
+ *
+ * TODO: This quirk 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 +4980,13 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev)
 	ctrl |= (cap & PCI_ACS_CR);
 	ctrl |= (cap & PCI_ACS_UF);
 
+	/* Enable Translation Blocking for external devices */
+	if (dev->external_facing || dev->untrusted)
+		if (cap & PCI_ACS_TB)
+			ctrl |= PCI_ACS_TB;
+		else
+			pci_warn(dev, "ACS: No Trans Blocking on ext dev\n");
+
 	pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl);
 
 	pci_info(dev, "Intel SPT PCH root port ACS workaround enabled\n");
-- 
2.27.0.212.ge8ba1cc988-goog