Messages in this thread | | | Subject | Re: [PATCH] iommu/vt-d: Don't apply gfx quirks to untrusted devices | From | Lu Baolu <> | Date | Tue, 2 Jun 2020 15:15:12 +0800 |
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On 2020/6/2 13:45, Rajat Jain wrote: > Currently, an external malicious PCI device can masquerade the VID:PID > of faulty gfx devices, and thus apply iommu quirks to effectively > disable the IOMMU restrictions for itself. > > Thus we need to ensure that the device we are applying quirks to, is > indeed an internal trusted device. >
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Best regards, baolu
> Signed-off-by: Rajat Jain <rajatja@google.com> > --- > drivers/iommu/intel-iommu.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index ef0a5246700e5..f2a480168a02f 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -6214,6 +6214,11 @@ const struct iommu_ops intel_iommu_ops = { > > static void quirk_iommu_igfx(struct pci_dev *dev) > { > + if (dev->untrusted) { > + pci_warn(dev, "skipping iommu quirk for untrusted gfx dev\n"); > + return; > + } > + > pci_info(dev, "Disabling IOMMU for graphics on this chipset\n"); > dmar_map_gfx = 0; > } > @@ -6255,6 +6260,11 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x163D, quirk_iommu_igfx); > > static void quirk_iommu_rwbf(struct pci_dev *dev) > { > + if (dev->untrusted) { > + pci_warn(dev, "skipping iommu quirk for untrusted dev\n"); > + return; > + } > + > /* > * Mobile 4 Series Chipset neglects to set RWBF capability, > * but needs it. Same seems to hold for the desktop versions. > @@ -6285,6 +6295,11 @@ static void quirk_calpella_no_shadow_gtt(struct pci_dev *dev) > { > unsigned short ggc; > > + if (dev->untrusted) { > + pci_warn(dev, "skipping iommu quirk for untrusted gfx dev\n"); > + return; > + } > + > if (pci_read_config_word(dev, GGC, &ggc)) > return; > > @@ -6318,6 +6333,13 @@ static void __init check_tylersburg_isoch(void) > pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x3a3e, NULL); > if (!pdev) > return; > + > + if (pdev->untrusted) { > + pci_warn(pdev, "skipping iommu quirk due to untrusted dev\n"); > + pci_dev_put(pdev); > + return; > + } > + > pci_dev_put(pdev); > > /* System Management Registers. Might be hidden, in which case > @@ -6327,6 +6349,12 @@ static void __init check_tylersburg_isoch(void) > if (!pdev) > return; > > + if (pdev->untrusted) { > + pci_warn(pdev, "skipping iommu quirk due to untrusted dev\n"); > + pci_dev_put(pdev); > + return; > + } > + > if (pci_read_config_dword(pdev, 0x188, &vtisochctrl)) { > pci_dev_put(pdev); > return; >
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