* [PATCH 1/2] PCI/ACPI: Support Microsoft's "DmaProperty"
2024-11-13 20:22 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Joshua Peraza
@ 2024-11-13 20:22 ` Joshua Peraza
2024-11-13 20:22 ` [PATCH 2/2] PCI: Rename pci_dev->untrusted to pci_dev->untrusted_dma Joshua Peraza
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Joshua Peraza @ 2024-11-13 20:22 UTC (permalink / raw)
To: rajatja
Cc: baolu.lu, bhelgaas, dtor, dwmw2, gregkh, helgaas, iommu,
jean-philippe, joro, jsbarnes, lenb, linux-acpi, linux-kernel,
linux-pci, mika.westerberg, oohall, pavel, rafael.j.wysocki,
rafael, rajatxjain, will, Joshua Peraza
From: Rajat Jain <rajatja@google.com>
The "DmaProperty" is supported and currently documented and used by
Microsoft [link 1 below], to flag internal PCIe root ports that need
DMA protection [link 2 below]. We have discussed with them and reached
a common understanding that they shall change their MSDN documentation
to say that the same property can be used to protect any PCI device,
and not just internal PCIe root ports (since there is no point
introducing yet another property for arbitrary PCI devices). This helps
with security from internal devices that offer an attack surface for
DMA attacks (e.g. internal network devices).
Support DmaProperty to mark DMA from a PCI device as untrusted.
Link: [1] https://docs.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#identifying-internal-pcie-ports-accessible-to-users-and-requiring-dma-protection
Link: [2] https://docs.microsoft.com/en-us/windows/security/information-protection/kernel-dma-protection-for-thunderbolt
Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Joshua Peraza <jperaza@google.com>
---
drivers/acpi/property.c | 3 +++
drivers/pci/pci-acpi.c | 22 ++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index 80a52a4e66dd..139e042ad2cb 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -56,6 +56,9 @@ static const guid_t prp_guids[] = {
/* Storage device needs D3 GUID: 5025030f-842f-4ab4-a561-99a5189762d0 */
GUID_INIT(0x5025030f, 0x842f, 0x4ab4,
0xa5, 0x61, 0x99, 0xa5, 0x18, 0x97, 0x62, 0xd0),
+ /* DmaProperty for PCI devices GUID: 70d24161-6dd5-4c9e-8070-705531292865 */
+ GUID_INIT(0x70d24161, 0x6dd5, 0x4c9e,
+ 0x80, 0x70, 0x70, 0x55, 0x31, 0x29, 0x28, 0x65),
};
/* ACPI _DSD data subnodes GUID [1]: dbb8e3e6-5886-4ba6-8795-1319f52a966b */
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index af370628e583..a457ae3e811a 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1438,12 +1438,34 @@ static void pci_acpi_set_external_facing(struct pci_dev *dev)
dev->external_facing = 1;
}
+static int pci_dev_has_dma_property(struct pci_dev *dev)
+{
+ struct acpi_device *adev;
+ const union acpi_object *obj;
+
+ adev = ACPI_COMPANION(&dev->dev);
+ if (!adev)
+ return 0;
+
+ /*
+ * Property used by Microsoft Windows to enforce IOMMU DMA
+ * protection from any device, that the system may not fully trust;
+ * we'll honour it the same way.
+ */
+ if (!acpi_dev_get_property(adev, "DmaProperty", ACPI_TYPE_INTEGER,
+ &obj) && obj->integer.value == 1)
+ return 1;
+
+ return 0;
+}
+
void pci_acpi_setup(struct device *dev, struct acpi_device *adev)
{
struct pci_dev *pci_dev = to_pci_dev(dev);
pci_acpi_optimize_delay(pci_dev, adev->handle);
pci_acpi_set_external_facing(pci_dev);
+ pci_dev->untrusted |= pci_dev_has_dma_property(pci_dev);
pci_acpi_add_edr_notifier(pci_dev);
pci_acpi_add_pm_notifier(adev, pci_dev);
--
2.47.0.277.g8800431eea-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread* [PATCH 2/2] PCI: Rename pci_dev->untrusted to pci_dev->untrusted_dma
2024-11-13 20:22 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Joshua Peraza
2024-11-13 20:22 ` [PATCH 1/2] " Joshua Peraza
@ 2024-11-13 20:22 ` Joshua Peraza
2024-11-13 21:38 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Rajat Jain
2024-11-14 7:27 ` Greg KH
3 siblings, 0 replies; 7+ messages in thread
From: Joshua Peraza @ 2024-11-13 20:22 UTC (permalink / raw)
To: rajatja
Cc: baolu.lu, bhelgaas, dtor, dwmw2, gregkh, helgaas, iommu,
jean-philippe, joro, jsbarnes, lenb, linux-acpi, linux-kernel,
linux-pci, mika.westerberg, oohall, pavel, rafael.j.wysocki,
rafael, rajatxjain, will, Joshua Peraza
From: Rajat Jain <rajatja@google.com>
Rename the field to make it more clear, that the device can execute DMA
attacks on the system, and thus the system may need protection from
such attacks from this device.
No functional change intended.
Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Joshua Peraza <jperaza@google.com>
---
drivers/iommu/amd/iommu.c | 2 +-
drivers/iommu/dma-iommu.c | 12 ++++++------
drivers/iommu/intel/iommu.c | 2 +-
drivers/iommu/iommu.c | 2 +-
drivers/pci/ats.c | 2 +-
drivers/pci/pci-acpi.c | 2 +-
drivers/pci/pci.c | 2 +-
drivers/pci/probe.c | 8 ++++----
drivers/pci/quirks.c | 2 +-
include/linux/pci.h | 5 +++--
10 files changed, 20 insertions(+), 19 deletions(-)
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 8364cd6fa47d..baa86a0744bc 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2777,7 +2777,7 @@ static int amd_iommu_def_domain_type(struct device *dev)
return 0;
/* Always use DMA domain for untrusted device */
- if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted)
+ if (dev_is_pci(dev) && to_pci_dev(dev)->untrusted_dma)
return IOMMU_DOMAIN_DMA;
/*
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 2a9fa0c8cc00..78b537c23f3c 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -598,16 +598,16 @@ static int iova_reserve_iommu_regions(struct device *dev,
return ret;
}
-static bool dev_is_untrusted(struct device *dev)
+static bool dev_has_untrusted_dma(struct device *dev)
{
- return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
+ return dev_is_pci(dev) && to_pci_dev(dev)->untrusted_dma;
}
static bool dev_use_swiotlb(struct device *dev, size_t size,
enum dma_data_direction dir)
{
return IS_ENABLED(CONFIG_SWIOTLB) &&
- (dev_is_untrusted(dev) ||
+ (dev_has_untrusted_dma(dev) ||
dma_kmalloc_needs_bounce(dev, size, dir));
}
@@ -620,7 +620,7 @@ static bool dev_use_sg_swiotlb(struct device *dev, struct scatterlist *sg,
if (!IS_ENABLED(CONFIG_SWIOTLB))
return false;
- if (dev_is_untrusted(dev))
+ if (dev_has_untrusted_dma(dev))
return true;
/*
@@ -1197,7 +1197,7 @@ dma_addr_t iommu_dma_map_page(struct device *dev, struct page *page,
* swiotlb_tbl_map_single() has initialized the bounce buffer
* proper to the contents of the original memory buffer.
*/
- if (dev_is_untrusted(dev)) {
+ if (dev_has_untrusted_dma(dev)) {
size_t start, virt = (size_t)phys_to_virt(phys);
/* Pre-padding */
@@ -1738,7 +1738,7 @@ size_t iommu_dma_opt_mapping_size(void)
size_t iommu_dma_max_mapping_size(struct device *dev)
{
- if (dev_is_untrusted(dev))
+ if (dev_has_untrusted_dma(dev))
return swiotlb_max_mapping_size(dev);
return SIZE_MAX;
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index e860bc9439a2..42f310d238a6 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4234,7 +4234,7 @@ static bool intel_iommu_is_attach_deferred(struct device *dev)
*/
static bool risky_device(struct pci_dev *pdev)
{
- if (pdev->untrusted) {
+ if (pdev->untrusted_dma) {
pci_info(pdev,
"Skipping IOMMU quirk for dev [%04X:%04X] on untrusted PCI link\n",
pdev->vendor, pdev->device);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 83c8e617a2c5..8f436db65b37 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1745,7 +1745,7 @@ static int iommu_get_default_domain_type(struct iommu_group *group,
driver_type = iommu_get_def_domain_type(group, gdev->dev,
driver_type);
- if (dev_is_pci(gdev->dev) && to_pci_dev(gdev->dev)->untrusted) {
+ if (dev_is_pci(gdev->dev) && to_pci_dev(gdev->dev)->untrusted_dma) {
/*
* No ARM32 using systems will set untrusted, it cannot
* work.
diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index 6afff1f1b143..51f232897c03 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -43,7 +43,7 @@ bool pci_ats_supported(struct pci_dev *dev)
if (!dev->ats_cap)
return false;
- return (dev->untrusted == 0);
+ return (dev->untrusted_dma == 0);
}
EXPORT_SYMBOL_GPL(pci_ats_supported);
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index a457ae3e811a..12791a2533a9 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -1465,7 +1465,7 @@ void pci_acpi_setup(struct device *dev, struct acpi_device *adev)
pci_acpi_optimize_delay(pci_dev, adev->handle);
pci_acpi_set_external_facing(pci_dev);
- pci_dev->untrusted |= pci_dev_has_dma_property(pci_dev);
+ pci_dev->untrusted_dma |= pci_dev_has_dma_property(pci_dev);
pci_acpi_add_edr_notifier(pci_dev);
pci_acpi_add_pm_notifier(adev, pci_dev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 225a6cd2e9ca..1312df37f2cf 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1056,7 +1056,7 @@ static void pci_std_enable_acs(struct pci_dev *dev, struct pci_acs *caps)
caps->ctrl |= (caps->cap & PCI_ACS_UF);
/* Enable Translation Blocking for external devices and noats */
- if (pci_ats_disabled() || dev->external_facing || dev->untrusted)
+ if (pci_ats_disabled() || dev->external_facing || dev->untrusted_dma)
caps->ctrl |= (caps->cap & PCI_ACS_TB);
}
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index f1615805f5b0..065f886db0b4 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1631,7 +1631,7 @@ static void set_pcie_thunderbolt(struct pci_dev *dev)
dev->is_thunderbolt = 1;
}
-static void set_pcie_untrusted(struct pci_dev *dev)
+static void pci_set_untrusted_dma(struct pci_dev *dev)
{
struct pci_dev *parent;
@@ -1640,8 +1640,8 @@ static void set_pcie_untrusted(struct pci_dev *dev)
* untrusted as well.
*/
parent = pci_upstream_bridge(dev);
- if (parent && (parent->untrusted || parent->external_facing))
- dev->untrusted = true;
+ if (parent && (parent->untrusted_dma || parent->external_facing))
+ dev->untrusted_dma = true;
}
static void pci_set_removable(struct pci_dev *dev)
@@ -1945,7 +1945,7 @@ int pci_setup_device(struct pci_dev *dev)
/* Need to have dev->cfg_size ready */
set_pcie_thunderbolt(dev);
- set_pcie_untrusted(dev);
+ pci_set_untrusted_dma(dev);
/* "Unknown power state" */
dev->current_state = PCI_UNKNOWN;
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index dccb60c1d9cc..65624f4bbaf0 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5337,7 +5337,7 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev)
ctrl |= (cap & PCI_ACS_CR);
ctrl |= (cap & PCI_ACS_UF);
- if (pci_ats_disabled() || dev->external_facing || dev->untrusted)
+ if (pci_ats_disabled() || dev->external_facing || dev->untrusted_dma)
ctrl |= (cap & PCI_ACS_TB);
pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 573b4c4c2be6..34b53b237077 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -444,13 +444,14 @@ struct pci_dev {
unsigned int shpc_managed:1; /* SHPC owned by shpchp */
unsigned int is_thunderbolt:1; /* Thunderbolt controller */
/*
- * Devices marked being untrusted are the ones that can potentially
+ * Devices marked with untrusted_dma are the ones that can potentially
* execute DMA attacks and similar. They are typically connected
* through external ports such as Thunderbolt but not limited to
* that. When an IOMMU is enabled they should be getting full
* mappings to make sure they cannot access arbitrary memory.
*/
- unsigned int untrusted:1;
+ unsigned int untrusted_dma:1;
+
/*
* Info from the platform, e.g., ACPI or device tree, may mark a
* device as "external-facing". An external-facing device is
--
2.47.0.277.g8800431eea-goog
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty"
2024-11-13 20:22 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Joshua Peraza
2024-11-13 20:22 ` [PATCH 1/2] " Joshua Peraza
2024-11-13 20:22 ` [PATCH 2/2] PCI: Rename pci_dev->untrusted to pci_dev->untrusted_dma Joshua Peraza
@ 2024-11-13 21:38 ` Rajat Jain
2024-11-14 7:27 ` Greg KH
3 siblings, 0 replies; 7+ messages in thread
From: Rajat Jain @ 2024-11-13 21:38 UTC (permalink / raw)
To: Joshua Peraza
Cc: baolu.lu, bhelgaas, dtor, dwmw2, gregkh, helgaas, iommu,
jean-philippe, joro, jsbarnes, lenb, linux-acpi, linux-kernel,
linux-pci, mika.westerberg, oohall, pavel, rafael.j.wysocki,
rafael, rajatxjain, will
On Wed, Nov 13, 2024 at 12:22 PM Joshua Peraza <jperaza@google.com> wrote:
>
> This patchset rebases two previously posted patches supporting
> recognition of Microsoft's DmaProperty.
>
> Rajat Jain (2):
> PCI/ACPI: Support Microsoft's "DmaProperty"
> PCI: Rename pci_dev->untrusted to pci_dev->untrusted_dma
Thanks for resending. This probably dropped off my radar since I moved
on to other things. But I can confirm a lot of Chromebooks today in
the market already use this property (and this patchset) for
identifying untrusted DMA capable devices.
Thanks & Best Regards,
Rajat
>
> drivers/acpi/property.c | 3 +++
> drivers/iommu/amd/iommu.c | 2 +-
> drivers/iommu/dma-iommu.c | 12 ++++++------
> drivers/iommu/intel/iommu.c | 2 +-
> drivers/iommu/iommu.c | 2 +-
> drivers/pci/ats.c | 2 +-
> drivers/pci/pci-acpi.c | 22 ++++++++++++++++++++++
> drivers/pci/pci.c | 2 +-
> drivers/pci/probe.c | 8 ++++----
> drivers/pci/quirks.c | 2 +-
> include/linux/pci.h | 5 +++--
> 11 files changed, 44 insertions(+), 18 deletions(-)
>
>
> base-commit: 2d5404caa8c7bb5c4e0435f94b28834ae5456623
> --
> 2.47.0.277.g8800431eea-goog
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty"
2024-11-13 20:22 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Joshua Peraza
` (2 preceding siblings ...)
2024-11-13 21:38 ` [PATCH 0/2] PCI/ACPI: Support Microsoft's "DmaProperty" Rajat Jain
@ 2024-11-14 7:27 ` Greg KH
3 siblings, 0 replies; 7+ messages in thread
From: Greg KH @ 2024-11-14 7:27 UTC (permalink / raw)
To: Joshua Peraza
Cc: rajatja, baolu.lu, bhelgaas, dtor, dwmw2, helgaas, iommu,
jean-philippe, joro, jsbarnes, lenb, linux-acpi, linux-kernel,
linux-pci, mika.westerberg, oohall, pavel, rafael.j.wysocki,
rafael, rajatxjain, will
On Wed, Nov 13, 2024 at 08:22:12PM +0000, Joshua Peraza wrote:
> This patchset rebases two previously posted patches supporting
> recognition of Microsoft's DmaProperty.
>
> Rajat Jain (2):
> PCI/ACPI: Support Microsoft's "DmaProperty"
> PCI: Rename pci_dev->untrusted to pci_dev->untrusted_dma
I thought we went through a lot of different choices when picking this
name, and explicitly did NOT use the "_dma" term here for a reason. Can
you go and read those old patch submissions to verify why we did so, and
what has changed since then and then document here what has changed to
allow this name change now?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 7+ messages in thread