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Diffstat (limited to 'add-acs-overrides.patch')
| -rw-r--r-- | add-acs-overrides.patch | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/add-acs-overrides.patch b/add-acs-overrides.patch new file mode 100644 index 000000000000..31ef973665e6 --- /dev/null +++ b/add-acs-overrides.patch @@ -0,0 +1,195 @@ +From 0457fc4aaca4bc954154347b209d1da78ba7f2d7 Mon Sep 17 00:00:00 2001 +From: Mark Weiman <mark.weiman@markzz.com> +Date: Wed, 7 Feb 2018 16:04:03 -0500 +Subject: [PATCH] pci: Enable overrides for missing ACS capabilities (4.15) + +This an updated version of Alex Williamson's patch from: +https://lkml.org/lkml/2013/5/30/513 + +Original commit message follows: +--- +PCIe ACS (Access Control Services) is the PCIe 2.0+ feature that +allows us to control whether transactions are allowed to be redirected +in various subnodes of a PCIe topology. For instance, if two +endpoints are below a root port or downsteam switch port, the +downstream port may optionally redirect transactions between the +devices, bypassing upstream devices. The same can happen internally +on multifunction devices. The transaction may never be visible to the +upstream devices. + +One upstream device that we particularly care about is the IOMMU. If +a redirection occurs in the topology below the IOMMU, then the IOMMU +cannot provide isolation between devices. This is why the PCIe spec +encourages topologies to include ACS support. Without it, we have to +assume peer-to-peer DMA within a hierarchy can bypass IOMMU isolation. + +Unfortunately, far too many topologies do not support ACS to make this +a steadfast requirement. Even the latest chipsets from Intel are only +sporadically supporting ACS. We have trouble getting interconnect +vendors to include the PCIe spec required PCIe capability, let alone +suggested features. + +Therefore, we need to add some flexibility. The pcie_acs_override= +boot option lets users opt-in specific devices or sets of devices to +assume ACS support. The "downstream" option assumes full ACS support +on root ports and downstream switch ports. The "multifunction" +option assumes the subset of ACS features available on multifunction +endpoints and upstream switch ports are supported. The "id:nnnn:nnnn" +option enables ACS support on devices matching the provided vendor +and device IDs, allowing more strategic ACS overrides. These options +may be combined in any order. A maximum of 16 id specific overrides +are available. It's suggested to use the most limited set of options +necessary to avoid completely disabling ACS across the topology. +Note to hardware vendors, we have facilities to permanently quirk +specific devices which enforce isolation but not provide an ACS +capability. Please contact me to have your devices added and save +your customers the hassle of this boot option. + +Signed-off-by: Mark Weiman <mark.weiman@markzz.com> +--- + Documentation/admin-guide/kernel-parameters.txt | 9 +++ + drivers/pci/quirks.c | 101 ++++++++++++++++++++++++ + 2 files changed, 110 insertions(+) + +diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt +index 46b26bfee27b..9018767828b0 100644 +--- a/Documentation/admin-guide/kernel-parameters.txt ++++ b/Documentation/admin-guide/kernel-parameters.txt +@@ -2966,6 +2966,15 @@ + 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 10684b17d0bd..091c8a0aca1e 100644 +--- a/drivers/pci/quirks.c ++++ b/drivers/pci/quirks.c +@@ -3680,6 +3680,106 @@ 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; ++} ++ + /* + * Following are device-specific reset methods which can be used to + * reset a single function if other methods (e.g. FLR, PM D0->D3) are +@@ -4512,6 +4612,7 @@ static const struct pci_dev_acs_enabled { + { PCI_VENDOR_ID_CAVIUM, PCI_ANY_ID, pci_quirk_cavium_acs }, + /* APM X-Gene */ + { PCI_VENDOR_ID_AMCC, 0xE004, pci_quirk_xgene_acs }, ++ { PCI_ANY_ID, PCI_ANY_ID, pcie_acs_overrides }, + { 0 } + }; + +-- +2.16.1 + |