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AJvYcCVlMHTLofEimpkjwlKrL0EpIxo9g5ApiLox0SkBe7PJguzgDOcD7B3o4tudambtkWqOVk+SFNCdB9K+rmc=@vger.kernel.org X-Gm-Message-State: AOJu0YxWgALeZv9ehHRXpnuGxl84l1qBb/ImPWdNSaIQu2Kh+WeiGn51 eXQnM3r3rymPQzwCB2aSfawYwHZqojxS/cqF3vYOb2NaHDs0+pa2lyl+BRq8HVfTBr1Dz8iDoo2 81YAikA== X-Google-Smtp-Source: AGHT+IHZzxzrxbsH7efugqJJN045fO9BV+dY755bECYZbZkD2jqYlwQTWhUh9sEr1Ybvi6ir1vlrHFwdCahW X-Received: from pgar9.prod.google.com ([2002:a05:6a02:2e89:b0:ae1:b40f:fc2]) (user=jperaza job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:7011:b0:1ee:d7fa:5d8f with SMTP id adf61e73a8af0-1eef3d5a9dfmr1947981637.27.1740096594064; Thu, 20 Feb 2025 16:09:54 -0800 (PST) Date: Fri, 21 Feb 2025 00:09:40 +0000 In-Reply-To: <20250221000943.973221-1-jperaza@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250221000943.973221-1-jperaza@google.com> X-Mailer: git-send-email 2.48.1.601.g30ceb7b040-goog Message-ID: <20250221000943.973221-2-jperaza@google.com> Subject: [v9 PATCH 1/2] PCI/ACPI: Support Microsoft's "DmaProperty" From: Joshua Peraza To: gregkh@linuxfoundation.org Cc: baolu.lu@linux.intel.com, bhelgaas@google.com, dtor@google.com, dwmw2@infradead.org, helgaas@kernel.org, iommu@lists.linux-foundation.org, jean-philippe@linaro.org, joro@8bytes.org, jperaza@google.com, jsbarnes@google.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, mika.westerberg@linux.intel.com, oohall@gmail.com, pavel@denx.de, rafael.j.wysocki@intel.com, rafael@kernel.org, rajatja@google.com, rajatxjain@gmail.com, will@kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Rajat Jain 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-an= d-requiring-dma-protection Link: [2] https://docs.microsoft.com/en-us/windows/security/information-pro= tection/kernel-dma-protection-for-thunderbolt Signed-off-by: Rajat Jain Reviewed-by: Mika Westerberg Acked-by: Rafael J. Wysocki Signed-off-by: Joshua Peraza Acked-by: Greg Kroah-Hartman --- 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 436019d96027..bb1459c43b6b 100644 --- a/drivers/acpi/property.c +++ b/drivers/acpi/property.c @@ -56,6 +56,9 @@ static const guid_t prp_guids[] =3D { /* 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), }; =20 /* 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 =3D 1; } =20 +static int pci_dev_has_dma_property(struct pci_dev *dev) +{ + struct acpi_device *adev; + const union acpi_object *obj; + + adev =3D 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 =3D=3D 1) + return 1; + + return 0; +} + void pci_acpi_setup(struct device *dev, struct acpi_device *adev) { struct pci_dev *pci_dev =3D to_pci_dev(dev); =20 pci_acpi_optimize_delay(pci_dev, adev->handle); pci_acpi_set_external_facing(pci_dev); + pci_dev->untrusted |=3D pci_dev_has_dma_property(pci_dev); pci_acpi_add_edr_notifier(pci_dev); =20 pci_acpi_add_pm_notifier(adev, pci_dev); --=20 2.48.1.601.g30ceb7b040-goog