Re: [PATCH] iommu/vt-d: Fix IOMMU lookup for VF's

[David Woodhouse]

On Fri, 2016-10-21 at 15:32 -0700, Ashok Raj wrote:
> IOMMU driver must pick the same IOMMU as that of a Physical Function (PF) for
> any of its Virtual Functions (VF). It is not practical to list all the VF's
> in the DMAR scope, as this list could be quite large. Linux also ignores any
> VF's listed in DMAR. See dmar_pci_bus_notifier() for virtfn handling.
> 
> Since the driver is looking for the bdf of the VF, it will not find one from
> searching the DRHD listed in BIOS.  As a result, the IOMMU driver associates
> the VF's under the INCLUDE_ALL iommu incorrectly.
> 
> This patch looks up the IOMMU of the PF when handling VF's.

I've made some cosmetic fixes — adding comments, and tweaking the
commit comment — and applied this to my tree. Thanks.

-- 
dwmw2




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[PATCH] iommu/vt-d: Fix IOMMU lookup for VF's

[Ashok Raj]

IOMMU driver must pick the same IOMMU as that of a Physical Function (PF) for
any of its Virtual Functions (VF). It is not practical to list all the VF's
in the DMAR scope, as this list could be quite large. Linux also ignores any
VF's listed in DMAR. See dmar_pci_bus_notifier() for virtfn handling.

Since the driver is looking for the bdf of the VF, it will not find one from
searching the DRHD listed in BIOS.  As a result, the IOMMU driver associates
the VF's under the INCLUDE_ALL iommu incorrectly.

This patch looks up the IOMMU of the PF when handling VF's.

Cc: David Woodhouse 
Cc: Joerg Roedel 
Cc: Ashok Raj 
Cc: Sainath Grandhi 
Cc: iommu@lists.linux-foundation.org
Cc: sta...@vger.kernel.org

Signed-off-by: Sainath Grandhi 
Signed-off-by: Ashok Raj 
---
 drivers/iommu/intel-iommu.c | 9 +
 1 file changed, 9 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a4407ea..c2e4b5c 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -885,6 +885,7 @@ static struct intel_iommu *device_to_iommu(struct device 
*dev, u8 *bus, u8 *devf
struct intel_iommu *iommu;
struct device *tmp;
struct pci_dev *ptmp, *pdev = NULL;
+   struct pci_dev *pf_pdev = NULL;
u16 segment = 0;
int i;
 
@@ -893,6 +894,11 @@ static struct intel_iommu *device_to_iommu(struct device 
*dev, u8 *bus, u8 *devf
 
if (dev_is_pci(dev)) {
pdev = to_pci_dev(dev);
+   /*
+* Always lookup the PF's IOMMU when handling VF's
+*/
+   pf_pdev = pci_physfn(pdev);
+   dev = &pf_pdev->dev;
segment = pci_domain_nr(pdev->bus);
} else if (has_acpi_companion(dev))
dev = &ACPI_COMPANION(dev)->dev;
@@ -905,6 +911,9 @@ static struct intel_iommu *device_to_iommu(struct device 
*dev, u8 *bus, u8 *devf
for_each_active_dev_scope(drhd->devices,
  drhd->devices_cnt, i, tmp) {
if (tmp == dev) {
+   if (pdev->is_virtfn)
+   goto got_pdev;
+
*bus = drhd->devices[i].bus;
*devfn = drhd->devices[i].devfn;
goto out;
-- 
2.7.4

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