ACS override patch on Fedora 22

edit

I patched my kernel on debian 4.1.3 with the following diff which seems to work (The virtual machines runs correctly). The following patch should also work in fc (I only moved the code from the previous patch at the correct position) :

diff -r b5e813034943 Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt   Mon Sep 07 19:26:43 2015 +0200
+++ b/Documentation/kernel-parameters.txt   Tue Sep 08 17:52:02 2015 +0200
@@ -2819,6 +2819,16 @@
        nomsi   Do not use MSI for native PCIe PME signaling (this makes
            all PCIe root ports use INTx for all services).

+   pcie_acs_override =
+           [PCIE] Override missing PCIe ACS support for:
+       downstream
+           All downstream ports - full ACS capabilties
+       multifunction
+           All multifunction devices - multifunction ACS subset
+       id:nnnn:nnnn
+           Specfic device - full ACS capabilities
+           Specified as vid:did (vendor/device ID) in hex
+
    pcmv=       [HW,PCMCIA] BadgePAD 4

    pd_ignore_unused
diff -r b5e813034943 drivers/pci/quirks.c
--- a/drivers/pci/quirks.c  Mon Sep 07 19:26:43 2015 +0200
+++ b/drivers/pci/quirks.c  Tue Sep 08 17:52:02 2015 +0200
@@ -3661,6 +3661,108 @@
 /* Intel 82801, https://bugzilla.kernel.org/show_bug.cgi?id=44881#c49 */
 DECLARE_PCI_FIXUP_HEADER(0x8086, 0x244e, quirk_use_pcie_bridge_dma_alias);

+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;
+}
+
+
 /*
  * AMD has indicated that the devices below do not support peer-to-peer
  * in any system where they are found in the southbridge with an AMD
@@ -3855,6 +3957,7 @@
    { PCI_VENDOR_ID_INTEL, 0x10D9, pci_quirk_mf_endpoint_acs },
    /* Intel PCH root ports */
    { PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_quirk_intel_pch_acs },
+    { PCI_ANY_ID, PCI_ANY_ID, pcie_acs_overrides },
    { 0x19a2, 0x710, pci_quirk_mf_endpoint_acs }, /* Emulex BE3-R */
    { 0x10df, 0x720, pci_quirk_mf_endpoint_acs ...