linux-kernel - [PATCH v2 5/7] amd_iommu: Make use of DMA quirks and ACS checks in IOMMU groups

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120530201931.31527.57970.stgit@bling.home>
Date:	Wed, 30 May 2012 14:19:31 -0600
From:	Alex Williamson <alex.williamson@...hat.com>
To:	joerg.roedel@....com, dwmw2@...radead.org,
	iommu@...ts.linux-foundation.org
Cc:	bhelgaas@...gle.com, benh@...nel.crashing.org, aik@...abs.ru,
	david@...son.dropbear.id.au, konrad.wilk@...cle.com,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	gregkh@...uxfoundation.org, ddutile@...hat.com,
	alex.williamson@...hat.com, liuj97@...il.com
Subject: [PATCH v2 5/7] amd_iommu: Make use of DMA quirks and ACS checks in
 IOMMU groups

Work around broken devices and adhere to ACS support when determining
IOMMU grouping.

Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
---

 drivers/iommu/amd_iommu.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index e072bd1..0e78d3c 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -254,6 +254,14 @@ static bool check_device(struct device *dev)
 	return true;
 }
 
+static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
+{
+	pci_dev_put(*from);
+	*from = to;
+}
+
+#define REQ_ACS_FLAGS	(PCI_ACS_SV | PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_UF)
+
 static int iommu_init_device(struct device *dev)
 {
 	struct pci_dev *dma_pdev, *pdev = to_pci_dev(dev);
@@ -286,6 +294,23 @@ static int iommu_init_device(struct device *dev)
 	} else
 		dma_pdev = pci_dev_get(pdev);
 
+	swap_pci_ref(&dma_pdev, pci_get_dma_source(dma_pdev));
+
+	if (dma_pdev->multifunction &&
+	    !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
+		swap_pci_ref(&dma_pdev,
+			     pci_get_slot(dma_pdev->bus,
+					  PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
+					  0)));
+
+	while (!pci_is_root_bus(dma_pdev->bus)) {
+		if (pci_acs_path_enabled(dma_pdev->bus->self,
+					 NULL, REQ_ACS_FLAGS))
+			break;
+
+		swap_pci_ref(&dma_pdev, pci_dev_get(dma_pdev->bus->self));
+	}
+
 	group = iommu_group_get(&dma_pdev->dev);
 	pci_dev_put(dma_pdev);
 	if (!group) {

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/