PCI: Add ACS quirk for Solarflare SFC9120 & SFC9140

Solarflare confirms that these devices do not allow peer-to-peer between
functions.  Quirk them to allow IOMMU grouping to expose this isolation.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Robert Stonehouse <rstonehouse@solarflare.com>

drivers/pci/quirks.c

@@ -3615,6 +3615,21 @@ static int pci_quirk_intel_pch_acs(struct pci_dev *dev, u16 acs_flags)
 	return acs_flags & ~flags ? 0 : 1;
 }
 
+static int pci_quirk_solarflare_acs(struct pci_dev *dev, u16 acs_flags)
+{
+	/*
+	 * SV, TB, and UF are not relevant to multifunction endpoints.
+	 *
+	 * Solarflare indicates that peer-to-peer between functions is not
+	 * possible, therefore RR, CR, and DT are not implemented.  Mask
+	 * these out as if they were clear in the ACS capabilities register.
+	 */
+	acs_flags &= ~(PCI_ACS_SV | PCI_ACS_TB | PCI_ACS_RR |
+		       PCI_ACS_CR | PCI_ACS_UF | PCI_ACS_DT);
+
+	return acs_flags ? 0 : 1;
+}
+
 static const struct pci_dev_acs_enabled {
 	u16 vendor;
 	u16 device;
@@ -3626,6 +3641,8 @@ static const struct pci_dev_acs_enabled {
 	{ PCI_VENDOR_ID_ATI, 0x439d, pci_quirk_amd_sb_acs },
 	{ PCI_VENDOR_ID_ATI, 0x4384, pci_quirk_amd_sb_acs },
 	{ PCI_VENDOR_ID_ATI, 0x4399, pci_quirk_amd_sb_acs },
+	{ PCI_VENDOR_ID_SOLARFLARE, 0x0903, pci_quirk_solarflare_acs },
+	{ PCI_VENDOR_ID_SOLARFLARE, 0x0923, pci_quirk_solarflare_acs },
 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_pch_acs },
 	{ 0 }
 };