releases/4.4.36/iommu-vt-d-fix-iommu-lookup-for-sr-iov-virtual-functions.patch

   1 From 1c387188c60f53b338c20eee32db055dfe022a9b Mon Sep 17 00:00:00 2001
   2 From: Ashok Raj <ashok.raj@intel.com>
   3 Date: Fri, 21 Oct 2016 15:32:05 -0700
   4 Subject: iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions
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   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 From: Ashok Raj <ashok.raj@intel.com>
  10
  11 commit 1c387188c60f53b338c20eee32db055dfe022a9b upstream.
  12
  13 The VT-d specification (§8.3.3) says:
  14     ‘Virtual Functions’ of a ‘Physical Function’ are under the scope
  15     of the same remapping unit as the ‘Physical Function’.
  16
  17 The BIOS is not required to list all the possible VFs in the scope
  18 tables, and arguably *shouldn't* make any attempt to do so, since there
  19 could be a huge number of them.
  20
  21 This has been broken basically for ever — the VF is never going to match
  22 against a specific unit's scope, so it ends up being assigned to the
  23 INCLUDE_ALL IOMMU. Which was always actually correct by coincidence, but
  24 now we're looking at Root-Complex integrated devices with SR-IOV support
  25 it's going to start being wrong.
  26
  27 Fix it to simply use pci_physfn() before doing the lookup for PCI devices.
  28
  29 Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
  30 Signed-off-by: Ashok Raj <ashok.raj@intel.com>
  31 Signed-off-by: David Woodhouse <dwmw2@infradead.org>
  32 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  33
  34 ---
  35  drivers/iommu/dmar.c        |    4 +++-
  36  drivers/iommu/intel-iommu.c |   13 +++++++++++++
  37  2 files changed, 16 insertions(+), 1 deletion(-)
  38
  39 --- a/drivers/iommu/dmar.c
  40 +++ b/drivers/iommu/dmar.c
  41 @@ -326,7 +326,9 @@ static int dmar_pci_bus_notifier(struct
  42         struct pci_dev *pdev = to_pci_dev(data);
  43         struct dmar_pci_notify_info *info;
  44
  45 -       /* Only care about add/remove events for physical functions */
  46 +       /* Only care about add/remove events for physical functions.
  47 +        * For VFs we actually do the lookup based on the corresponding
  48 +        * PF in device_to_iommu() anyway. */
  49         if (pdev->is_virtfn)
  50                 return NOTIFY_DONE;
  51         if (action != BUS_NOTIFY_ADD_DEVICE &&
  52 --- a/drivers/iommu/intel-iommu.c
  53 +++ b/drivers/iommu/intel-iommu.c
  54 @@ -885,7 +885,13 @@ static struct intel_iommu *device_to_iom
  55                 return NULL;
  56
  57         if (dev_is_pci(dev)) {
  58 +               struct pci_dev *pf_pdev;
  59 +
  60                 pdev = to_pci_dev(dev);
  61 +               /* VFs aren't listed in scope tables; we need to look up
  62 +                * the PF instead to find the IOMMU. */
  63 +               pf_pdev = pci_physfn(pdev);
  64 +               dev = &pf_pdev->dev;
  65                 segment = pci_domain_nr(pdev->bus);
  66         } else if (has_acpi_companion(dev))
  67                 dev = &ACPI_COMPANION(dev)->dev;
  68 @@ -898,6 +904,13 @@ static struct intel_iommu *device_to_iom
  69                 for_each_active_dev_scope(drhd->devices,
  70                                           drhd->devices_cnt, i, tmp) {
  71                         if (tmp == dev) {
  72 +                               /* For a VF use its original BDF# not that of the PF
  73 +                                * which we used for the IOMMU lookup. Strictly speaking
  74 +                                * we could do this for all PCI devices; we only need to
  75 +                                * get the BDF# from the scope table for ACPI matches. */
  76 +                               if (pdev->is_virtfn)
  77 +                                       goto got_pdev;
  78 +
  79                                 *bus = drhd->devices[i].bus;
  80                                 *devfn = drhd->devices[i].devfn;
  81                                 goto out;