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diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2fba824..a797d74 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3922,6 +3922,14 @@
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
+ pci_acs_override [PCIE] Override missing PCIe ACS support for:
+ downstream
+ All downstream ports - full ACS capabilities
+ multifunction
+ Add multifunction devices - multifunction ACS subset
+ id:nnnn:nnnn
+ Specific device - full ACS capabilities
+ Specified as vid:did (vendor/device ID) in hex
noioapicquirk [APIC] Disable all boot interrupt quirks.
Safety option to keep boot IRQs enabled. This
should never be necessary.
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 003950c..d3bb542 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -193,6 +193,107 @@ static int __init pci_apply_final_quirks(void)
}
fs_initcall_sync(pci_apply_final_quirks);
+static bool acs_on_downstream;
+static bool acs_on_multifunction;
+
+#define NUM_ACS_IDS 16
+struct acs_on_id {
+ unsigned short vendor;
+ unsigned short device;
+};
+
+static struct acs_on_id acs_on_ids[NUM_ACS_IDS];
+static u8 max_acs_id;
+
+static __init int pcie_acs_override_setup(char *p)
+{
+ if (!p)
+ return -EINVAL;
+
+ while (*p) {
+ if (!strncmp(p, "downstream", 10))
+ acs_on_downstream = true;
+ if (!strncmp(p, "multifunction", 13))
+ acs_on_multifunction = true;
+ if (!strncmp(p, "id:", 3)) {
+ char opt[5];
+ int ret;
+ long val;
+
+ if (max_acs_id >= NUM_ACS_IDS - 1) {
+ pr_warn("Out of PCIe ACS override slots (%d)\n",
+ NUM_ACS_IDS);
+ goto next;
+ }
+
+ p += 3;
+ snprintf(opt, 5, "%s", p);
+ ret = kstrtol(opt, 16, &val);
+ if (ret) {
+ pr_warn("PCIe ACS ID parse error %d\n", ret);
+ goto next;
+ }
+ acs_on_ids[max_acs_id].vendor = val;
+ p += strcspn(p, ":");
+ if (*p != ':') {
+ pr_warn("PCIe ACS invalid ID\n");
+ goto next;
+ }
+
+ p++;
+ snprintf(opt, 5, "%s", p);
+ ret = kstrtol(opt, 16, &val);
+ if (ret) {
+ pr_warn("PCIe ACS ID parse error %d\n", ret);
+ goto next;
+ }
+ acs_on_ids[max_acs_id].device = val;
+ max_acs_id++;
+ }
+next:
+ p += strcspn(p, ",");
+ if (*p == ',')
+ p++;
+ }
+
+ if (acs_on_downstream || acs_on_multifunction || max_acs_id)
+ pr_warn("Warning: PCIe ACS overrides enabled; This may allow non-IOMMU protected peer-to-peer DMA\n");
+
+ return 0;
+}
+early_param("pcie_acs_override", pcie_acs_override_setup);
+
+static int pcie_acs_overrides(struct pci_dev *dev, u16 acs_flags)
+{
+ int i;
+
+ /* Never override ACS for legacy devices or devices with ACS caps */
+ if (!pci_is_pcie(dev) ||
+ pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ACS))
+ return -ENOTTY;
+
+ for (i = 0; i < max_acs_id; i++)
+ if (acs_on_ids[i].vendor == dev->vendor &&
+ acs_on_ids[i].device == dev->device)
+ return 1;
+
+switch (pci_pcie_type(dev)) {
+ case PCI_EXP_TYPE_DOWNSTREAM:
+ case PCI_EXP_TYPE_ROOT_PORT:
+ if (acs_on_downstream)
+ return 1;
+ break;
+ case PCI_EXP_TYPE_ENDPOINT:
+ case PCI_EXP_TYPE_UPSTREAM:
+ case PCI_EXP_TYPE_LEG_END:
+ case PCI_EXP_TYPE_RC_END:
+ if (acs_on_multifunction && dev->multifunction)
+ return 1;
+ }
+
+ return -ENOTTY;
+}
+
/*
* Decoding should be disabled for a PCI device during BAR sizing to avoid
* conflict. But doing so may cause problems on host bridge and perhaps other
@@ -4950,6 +5051,8 @@ static const struct pci_dev_acs_enabled {
{ PCI_VENDOR_ID_NXP, 0x8d9b, pci_quirk_nxp_rp_acs },
/* Zhaoxin Root/Downstream Ports */
{ PCI_VENDOR_ID_ZHAOXIN, PCI_ANY_ID, pci_quirk_zhaoxin_pcie_ports_acs },
+ /* allow acs for any */
+ { PCI_ANY_ID, PCI_ANY_ID, pcie_acs_overrides },
{ 0 }
};
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