[PATCH common] SysFSTools: add phys/virtfns to verbose output

[Dominik Csapak <d.csapak@proxmox.com>]

with this we can show/detect devices that belong together, e.g. the virtfns of
a vGPU device.

This can be helpful in a tree style display of virtfns to physfns or
when trying to determine which virtfns belong to a specific device, etc.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
Sending this as preparation for some things i want to do and though
it can't harm to have that information already. Places where we'd use
that info are:

* A overview over pci devices per node (e.g. to simplify creating
  resource mappings)

* Introducing vGPU/PCI allocation policies (e.g. dense or spread out),
  for this we need to know the correlation between vGPUs and their
  physical device

 src/PVE/SysFSTools.pm | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/src/PVE/SysFSTools.pm b/src/PVE/SysFSTools.pm
index a00fbcb..d6b92fb 100644
--- a/src/PVE/SysFSTools.pm
+++ b/src/PVE/SysFSTools.pm
@@ -138,6 +138,29 @@ sub lspci {
                 $res->{subsystem_device} = $sub_device if defined($sub_device);
                 $res->{subsystem_vendor_name} = $sub_vendor_name if defined($sub_vendor_name);
                 $res->{subsystem_device_name} = $sub_device_name if defined($sub_device_name);
+
+                my $physfn_device = readlink("$devdir/physfn");
+                # usually this results in "../<pci-id>'
+                if ($physfn_device =~ m!/(${pciregex})$!) {
+                    $res->{physfn} = $1;
+                }
+
+                my $virtfns = [];
+                dir_glob_foreach(
+                    $devdir,
+                    'virtfn\d+',
+                    sub {
+                        my ($virtfn) = @_;
+                        my $virtfn_device = readlink("$devdir/$virtfn");
+                        # usually this results in "../<pci-id>'
+                        if ($virtfn_device =~ m!/(${pciregex})$!) {
+                            push $virtfns->@*, { $virtfn => $1 };
+                        }
+
+                    },
+                );
+
+                $res->{virtfns} = $virtfns if scalar($virtfns->@*) > 0;
             }
 
             push @$devices, $res;
-- 
2.47.3