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[Xen-devel] [PATCH v6] VT-d: fix VF of RC integrated PF matched to wrong VT-d unit

The problem is for 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.

If a PF is an extended function, the BDF of a traditional function
within the same device should be used to search VT-d unit. Otherwise,
the real BDF of PF should be used. According PCI-e spec, an extended
function is a function within an ARI device and Function Number is
greater than 7. The original code tried to tell apart Extended
Function and non-Extended Function through checking PCI_SLOT(),
missing counterpart of pci_ari_enabled() (this function exists in
linux kernel) compared to linux kernel. Without checking whether ARI
is enabled, it incurs a RC integrated PF with PCI_SLOT() >0 is wrongly
classified to an extended function. Note that a RC integrated function
isn't within an ARI device and thus cannot be extended function and in
this case the real BDF should be used.

This patch introduces a new field, pf_is_extfn, in struct
pci_dev_info, to indicate whether the physical function is an extended
function. The new field helps to generate correct BDF to search VT-d

Reported-by: Crawford, Eric R <Eric.R.Crawford@xxxxxxxxx>
Tested-by: Crawford, Eric R <Eric.R.Crawford@xxxxxxxxx>
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
 xen/drivers/passthrough/pci.c      | 6 +++++-
 xen/drivers/passthrough/vtd/dmar.c | 2 +-
 xen/include/xen/pci.h              | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
index 27bdb71..8c2ba33 100644
--- a/xen/drivers/passthrough/pci.c
+++ b/xen/drivers/passthrough/pci.c
@@ -599,6 +599,7 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
     unsigned int slot = PCI_SLOT(devfn), func = PCI_FUNC(devfn);
     const char *pdev_type;
     int ret;
+    bool pf_is_extfn = false;
     if (!info)
         pdev_type = "device";
@@ -609,7 +610,9 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
         pdev = pci_get_pdev(seg, info->physfn.bus, info->physfn.devfn);
-        if ( !pdev )
+        if ( pdev )
+            pf_is_extfn = pdev->info.is_extfn;
+        else
             pci_add_device(seg, info->physfn.bus, info->physfn.devfn,
                            NULL, node);
         pdev_type = "virtual function";
@@ -707,6 +710,7 @@ int pci_add_device(u16 seg, u8 bus, u8 devfn,
                    seg, bus, slot, func, ctrl);
+    pdev->info.pf_is_extfn = pf_is_extfn;
     ret = 0;
diff --git a/xen/drivers/passthrough/vtd/dmar.c 
index 82040dd..a96558f 100644
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -219,7 +219,7 @@ struct acpi_drhd_unit *acpi_find_matched_drhd_unit(const 
struct pci_dev *pdev)
     else if ( pdev->info.is_virtfn )
         bus = pdev->info.physfn.bus;
-        devfn = PCI_SLOT(pdev->info.physfn.devfn) ? 0 : 
+        devfn = pdev->info.pf_is_extfn ? 0 : pdev->info.physfn.devfn;
diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
index 59b6e8a..9e76aa0 100644
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -40,6 +40,7 @@
 struct pci_dev_info {
     bool_t is_extfn;
+    bool_t pf_is_extfn; /* Only valid for virtual function */
     bool_t is_virtfn;
     struct {
         u8 bus;

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