[PATCH v5 11/11] drm/xe/configfs: Allow adding configurations for future VFs

[Michal Wajdeczko]

Since we are expecting that all configuration directory names
will match some of the existing devices, we can't provide any
configuration for the VFs until they are actually enabled.

But we can relax that restriction by just checking if there
is a PF device that could create given VF. This is easy since
all our PF devices are always present at function 0 and we can
query PF device for number of VFs it could support.

Then for some system with PF device at 0000:00:02.0 we can add
configs for all VFs:

  /sys/kernel/config/xe/
  ├── 0000:00:02.0
  │   └── ...
  ├── 0000:00:02.1
  │   └── ...
  ├── 0000:00:02.2
  │   └── ...
  :
  └── 0000:00:02.7
      └── ...

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Lucas De Marchi <lucas.demarchi at intel.com>
---
v2: rebase and improve checks, fix include order
v3: put correct device (Lucas)
---
 drivers/gpu/drm/xe/xe_configfs.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 766775772eef..da9a8e64621f 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -12,9 +12,9 @@
 #include <linux/string.h>
 
 #include "xe_configfs.h"
-#include "xe_module.h"
-
 #include "xe_hw_engine_types.h"
+#include "xe_module.h"
+#include "xe_pci_types.h"
 
 /**
  * DOC: Xe Configfs
@@ -285,6 +285,15 @@ static const struct xe_device_desc *xe_match_desc(struct pci_dev *pdev)
 	return found ? (const void *)found->driver_data : NULL;
 }
 
+static struct pci_dev *get_physfn_instead(struct pci_dev *virtfn)
+{
+	struct pci_dev *physfn = pci_physfn(virtfn);
+
+	pci_dev_get(physfn);
+	pci_dev_put(virtfn);
+	return physfn;
+}
+
 static struct config_group *xe_config_make_device_group(struct config_group *group,
 							const char *name)
 {
@@ -306,11 +315,22 @@ static struct config_group *xe_config_make_device_group(struct config_group *gro
 		return ERR_PTR(-EINVAL);
 
 	pdev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(slot, function));
+	if (!pdev && function)
+		pdev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(slot, 0));
+	if (!pdev && slot)
+		pdev = pci_get_domain_bus_and_slot(domain, bus, PCI_DEVFN(0, 0));
 	if (!pdev)
 		return ERR_PTR(-ENODEV);
+	pdev = get_physfn_instead(pdev);
 
 	match = xe_match_desc(pdev);
+	if (match) {
+		int vfnumber = PCI_DEVFN(slot, function) - pdev->devfn;
 
+		if (vfnumber && (!dev_is_pf(&pdev->dev) || !match->has_sriov ||
+				 vfnumber > pci_sriov_get_totalvfs(pdev)))
+			match = NULL;
+	}
 	pci_dev_put(pdev);
 
 	if (!match)
-- 
2.47.1