[Xen-devel] [PATCH v2] VT-d: fix VF of RC integrated endpoint matched to wrong VT-d unit

[Chao Gao <chao.gao@xxxxxxxxx>]

The problem is a VF of RC integrated PF (e.g. PF's BDF is 00:02.0),
we would wrongly use 00:00.0 to search VT-d unit.

To search VT-d unit for a VF, the BDF of the PF is used. And If the
PF is an Extended Function, the BDF of one traditional function is
used.  The following line (from acpi_find_matched_drhd_unit()):
    devfn = PCI_SLOT(pdev->info.physfn.devfn) ? 0 : pdev->info.physfn.devfn;
sets 'devfn' to 0 if PF's devfn > 7. Apparently, it treats all
PFs which has devfn > 7 as extended function. However, it is wrong for
a RC integrated PF, which is not ARI-capable but may have devfn > 7.

This patch directly looks up the 'is_extfn' field of PF's struct pci_dev
to decide whether the PF is a extended function.

Reported-by: Crawford Eric R <Eric.R.Crawford@xxxxxxxxx>
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
 xen/drivers/passthrough/vtd/dmar.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/xen/drivers/passthrough/vtd/dmar.c 
b/xen/drivers/passthrough/vtd/dmar.c
index 82040dd..3ba33c7 100644
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -218,8 +218,18 @@ struct acpi_drhd_unit *acpi_find_matched_drhd_unit(const 
struct pci_dev *pdev)
     }
     else if ( pdev->info.is_virtfn )
     {
+        struct pci_dev *physfn;
+
         bus = pdev->info.physfn.bus;
-        devfn = PCI_SLOT(pdev->info.physfn.devfn) ? 0 : 
pdev->info.physfn.devfn;
+        /*
+         * Use 0 as 'devfn' to search VT-d unit when the physical function
+         * is an Extended Function.
+         */
+        pcidevs_lock();
+        physfn = pci_get_pdev(pdev->seg, bus, pdev->info.physfn.devfn);
+        pcidevs_unlock();
+        ASSERT(physfn);
+        devfn = physfn->info.is_extfn ? 0 : pdev->info.physfn.devfn;
     }
     else
     {
-- 
1.8.3.1


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