forked from AUR/linux-vfio
193 lines
6.4 KiB
Diff
193 lines
6.4 KiB
Diff
From 578d958c59002358abdeeb294c25ac28027b9f7a Mon Sep 17 00:00:00 2001
|
|
From: Mark Weiman <mark.weiman@markzz.com>
|
|
Date: Wed, 27 Jan 2021 13:28:09 -0500
|
|
Subject: [PATCH] pci: Enable overrides for missing ACS capabilities (5.10.11+)
|
|
|
|
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 devicstarting
|
|
---
|
|
.../admin-guide/kernel-parameters.txt | 8 ++
|
|
drivers/pci/quirks.c | 102 ++++++++++++++++++
|
|
2 files changed, 110 insertions(+)
|
|
|
|
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
|
|
index 26bfe7ae711b..7babcf646686 100644
|
|
--- a/Documentation/admin-guide/kernel-parameters.txt
|
|
+++ b/Documentation/admin-guide/kernel-parameters.txt
|
|
@@ -3629,6 +3629,14 @@
|
|
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 fb1dc11e7cc5..8748df0fe1e1 100644
|
|
--- a/drivers/pci/quirks.c
|
|
+++ b/drivers/pci/quirks.c
|
|
@@ -192,6 +192,106 @@ 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;
|
|
+}
|
|
+
|
|
/*
|
|
* 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
|
|
@@ -4769,6 +4869,8 @@ static const struct pci_dev_acs_enabled {
|
|
{ PCI_VENDOR_ID_ZHAOXIN, 0x9083, pci_quirk_mf_endpoint_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 }
|
|
};
|
|
|
|
--
|
|
2.30.0
|
|
|