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PCI: Treat "external-facing" devices themselves as internal

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"External-facing" devices are internal devices that expose PCIe hierarchies
such as Thunderbolt outside the platform [1].  Previously these internal
devices were marked as "untrusted" the same as devices downstream from
them.

Use the ACPI or DT information to identify external-facing devices, but
only mark the devices *downstream* from them as "untrusted" [2].  The
external-facing device itself is no longer marked as untrusted.

[1] https://docs.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#identifying-externally-exposed-pcie-root-ports
[2] https://lore.kernel.org/linux-pci/20200610230906.GA1528594@bjorn-Precision-5520/
Link: https://lore.kernel.org/r/20200707224604.3737893-3-rajatja@google.com
Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Rajat Jain
2020-07-07 15:46:03 -07:00
committed by Bjorn Helgaas
parent 52fbf5bdee
commit 99b50be9d8
5 changed files with 15 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/iommu/intel/iommu.c
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@@ -4730,12 +4730,12 @@ const struct attribute_group *intel_iommu_groups[] = {
NULL, NULL,
}; };
static inline bool has_untrusted_dev(void) static inline bool has_external_pci(void)
{ {
struct pci_dev *pdev = NULL; struct pci_dev *pdev = NULL;
for_each_pci_dev(pdev) for_each_pci_dev(pdev)
if (pdev->untrusted) if (pdev->external_facing)
return true; return true;
return false; return false;
@@ -4743,7 +4743,7 @@ static inline bool has_untrusted_dev(void)
static int __init platform_optin_force_iommu(void) static int __init platform_optin_force_iommu(void)
{ {
if (!dmar_platform_optin() || no_platform_optin || !has_untrusted_dev()) if (!dmar_platform_optin() || no_platform_optin || !has_external_pci())
return 0; return 0;
if (no_iommu || dmar_disabled) if (no_iommu || dmar_disabled)

2
drivers/pci/of.c
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@@ -42,7 +42,7 @@ void pci_set_bus_of_node(struct pci_bus *bus)
} else { } else {
node = of_node_get(bus->self->dev.of_node); node = of_node_get(bus->self->dev.of_node);
if (node && of_property_read_bool(node, "external-facing")) if (node && of_property_read_bool(node, "external-facing"))
bus->self->untrusted = true; bus->self->external_facing = true;
} }
bus->dev.of_node = node; bus->dev.of_node = node;

9
drivers/pci/pci-acpi.c
View File

@@ -1213,7 +1213,7 @@ static void pci_acpi_optimize_delay(struct pci_dev *pdev,
ACPI_FREE(obj); ACPI_FREE(obj);
} }
static void pci_acpi_set_untrusted(struct pci_dev *dev) static void pci_acpi_set_external_facing(struct pci_dev *dev)
{ {
u8 val; u8 val;
@@ -1224,11 +1224,10 @@ static void pci_acpi_set_untrusted(struct pci_dev *dev)
/* /*
* These root ports expose PCIe (including DMA) outside of the * These root ports expose PCIe (including DMA) outside of the
* system so make sure we treat them and everything behind as * system. Everything downstream from them is external.
* untrusted.
*/ */
if (val) if (val)
dev->untrusted = 1; dev->external_facing = 1;
} }
static void pci_acpi_setup(struct device *dev) static void pci_acpi_setup(struct device *dev)
@@ -1240,7 +1239,7 @@ static void pci_acpi_setup(struct device *dev)
return; return;
pci_acpi_optimize_delay(pci_dev, adev->handle); pci_acpi_optimize_delay(pci_dev, adev->handle);
pci_acpi_set_untrusted(pci_dev); pci_acpi_set_external_facing(pci_dev);
pci_acpi_add_edr_notifier(pci_dev); pci_acpi_add_edr_notifier(pci_dev);
pci_acpi_add_pm_notifier(adev, pci_dev); pci_acpi_add_pm_notifier(adev, pci_dev);

2
drivers/pci/probe.c
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@@ -1552,7 +1552,7 @@ static void set_pcie_untrusted(struct pci_dev *dev)
* untrusted as well. * untrusted as well.
*/ */
parent = pci_upstream_bridge(dev); parent = pci_upstream_bridge(dev);
if (parent && parent->untrusted) if (parent && (parent->untrusted || parent->external_facing))
dev->untrusted = true; dev->untrusted = true;
} }

6
include/linux/pci.h
View File

@@ -432,6 +432,12 @@ struct pci_dev {
* mappings to make sure they cannot access arbitrary memory. * mappings to make sure they cannot access arbitrary memory.
*/ */
unsigned int untrusted:1; unsigned int untrusted:1;
/*
* Info from the platform, e.g., ACPI or device tree, may mark a
* device as "external-facing". An external-facing device is
* itself internal but devices downstream from it are external.
*/
unsigned int external_facing:1;
unsigned int broken_intx_masking:1; /* INTx masking can't be used */ unsigned int broken_intx_masking:1; /* INTx masking can't be used */
unsigned int io_window_1k:1; /* Intel bridge 1K I/O windows */ unsigned int io_window_1k:1; /* Intel bridge 1K I/O windows */
unsigned int irq_managed:1; unsigned int irq_managed:1;