Introduce explicit OOT module mode in backport script

1. Add -k / --create-oot option (with --create-oot compatibility alias)
2. Keep default create-tree behavior as non-oot (exclude oot patches)
3. Make oot mode apply all patches, including oot patches using
./backport.sh -k
4. Update README usage/options and examples to document new behavior
5. This helps other components continue working on full-kernel
integration instead of being forced into oot-module-only flow.

Signed-off-by: Pravalika Gurram <pravalika.gurram@intel.com>

Author: pravalikagurram1

README.md

@@ -40,9 +40,29 @@ backport.sh < options >
 ||options |description |
 |-- |--|--| 
 |1. |create-tree| Create kernel tree based on given option <base/features> (default)|
-|2. |delete-tree| Delete the tree|
-|3. |reset-tree| Delete the existing tree and re-create it|
-|4. |override| Overrides existing tree|
+|2. |-k, --create-oot| Create tree for OOT modules and apply all patches including oot patches|
+|3. |delete-tree| Delete the tree|
+|4. |reset-tree| Delete the existing tree and re-create it|
+|5. |override| Overrides existing tree|
+
+### Patch application modes
+
+- `./backport.sh` (default): applies all patches except `backport/patches/oot/`.
+- `./backport.sh -c base`: applies only `backport/patches/base/`.
+- `./backport.sh -k` or `./backport.sh --create-oot`: applies all patches including `backport/patches/oot/`.
+
+### Examples
+
+```bash
+# default tree (base + features, no oot)
+./backport.sh
+
+# base-only tree
+./backport.sh -c base
+
+# oot module (all patches + oot patches)
+./backport.sh -k
+```
 
 # Debugging
 
@@ -88,6 +108,7 @@ Place the patch in the appropriate directory based on patch type:
 ```
 backport/patches/
 ├── base/           # All fixes and patches merged in drm-tip
+├── oot/            # oot-module specific patches
 └── features/       # Feature patches under review
     ├── eu-debug/
     ├── sriov/
@@ -96,12 +117,14 @@ backport/patches/
 
 #### Placement Rules:
 - **`backport/patches/base/`** - For all fixes and patches already merged in drm-tip
+- **`backport/patches/oot/`** - For oot-module-specific patches
 - **`backport/patches/features/<feature-name>/`** - For new feature patches under review
   - Place feature patches in the appropriate feature subdirectory
   - If the feature directory doesn't exist, create one with a descriptive name
 
 **Examples:**
 - Bug fix → `backport/patches/base/0001-fix-memory-leak.patch`
+- OOT update → `backport/patches/oot/0001-update-oot-build.patch`
 - SR-IOV feature → `backport/patches/features/sriov/0001-add-sriov-support.patch`
 - EU Debug feature → `backport/patches/features/eu-debug/0001-enable-eu-debug.patch`
 
@@ -110,6 +133,9 @@ backport/patches/
 # For base patches
 cp <your-patch>.patch backport/patches/base/
 
+# For oot patches
+cp <your-patch>.patch backport/patches/oot/
+
 # For feature patches
 cp <your-patch>.patch backport/patches/features/<feature-name>
 ```
@@ -147,6 +173,24 @@ After successful tree generation, verify your changes:
 - Create a pull request with clear description
 - Reference upstream commit or mailing list discussion
 
+## Adding OOT Patches
+
+Use this flow when creating patches specifically for OOT packaging.
+
+1. Create the change in the generated `kernel/` tree and export it as a patch.
+  ```bash
+  cd kernel
+  git format-patch -N1 <commit-hash> --zero-commit
+  ```
+
+2. Place the generated patch under `backport/patches/oot/` and add it to the `series` file.
+
+3. Run oot module creation:
+  ```bash
+  ./backport.sh -k
+  ```
+  This applies all patches including oot module patches.
+
 # License
 
 This work is a subset of the Linux kernel as such we keep the kernel's

backport.sh

@@ -22,43 +22,50 @@ fi
 
 KERNEL="linux-${KERNEL_TAG/v}"
 
-SHORT=:c,d,h,r,o
-LONG=create-tree:delete-tree,help,reset-tree,override
+SHORT=:c,d,h,r,o,k
+LONG=create-tree:delete-tree,help,reset-tree,override,create-oot
 OPTS=$(getopt -a --options $SHORT --longoptions $LONG -- "$@")
 
 flavor="features"
 is_existing_tree=0
 is_override=0
 xkb_tag=""
+is_oot_tree=0
+requested_flavor=""
 
 usage () {
           echo ""
-          echo "Usage: $0 [-c|--create-tree] [-d|--delete-tree] [-r|--reset-tree]"
+		  echo "Usage: $0 [-c|--create-tree] [-d|--delete-tree] [-r|--reset-tree] [-k|--create-oot]"
           echo ""
           echo "Options:"
           echo "  -c, --create-tree                   	Create kernel tree based on given option <base/features>"
           echo "  -d, --delete-tree    	      		Delete the tree"
           echo "  -r, --reset-tree    	      		Delete the existing tree and re-create it"
           echo "  -o, --override    	      		Overrides the existing tree"
+	  echo "  -k, --create-oot 			Create oot tree (includes oot patches)"
           exit 1
 }
 
 apply_patches() {
 	echo "Applying local patches"
 	while read p; do
-		case "$p" in \#*)
-			if [ ! -z "$flavor" ]; then
-				echo $p | tr -d "#" | (read name; echo "Applying $name patches..!" >&2)
-				if [[ "$flavor" == "base" ]]; then
-					echo "Only base patches will be  applied"
-					flavor=""
-				fi
+		# Ignore comments/blank lines from series
+		case "$p" in
+			""|\#*)
 				continue
-			else
-				break
-			fi
-			;;
+				;;
 		esac
+
+		# Patch selection policy:
+		#  - default: apply all except oot
+		#  - -c base: apply only base patches
+		#  - -k/--create-oot: apply all patches including oot
+		if [[ "$flavor" == "base" ]]; then
+			[[ "$p" == *"/base/"* ]] || continue
+		elif [[ $is_oot_tree -eq 0 ]]; then
+			[[ "$p" == *"/oot/"* ]] && continue
+		fi
+
 		git am -q -s "$WORKING_DIR/$p"
 		if [ $? -ne 0 ]; then
 			echo "Failed to apply patch $p"
@@ -140,43 +147,80 @@ delete_kernel_tree () {
 }
 
 xkb_tag=$(git -C $WORKING_DIR describe --always --tags)
+
 if [ ! $# -gt 0 ]; then
 	echo "No option provided, so proceeding with create-tree"
-        create_kernel_tree
+	create_kernel_tree
 fi
 
-while [ $# -gt 0 ]; do
-	for arg in "$@"
-	do
-		if [ "$arg" == "--override" ] || [ "$arg" == "-o" ]; then
-			is_override=1
-		fi
-	done
+eval set -- "$OPTS"
+action="create"
 
-        case $1 in
-                -c|--create-tree|-o|--override)
-			if [ ! $# -gt 1 ]; then
-				echo "No option provided for creating the tree"
+while true; do
+	case "$1" in
+		-c|--create-tree)
+			if [ -n "$2" ] && [ "$2" != "--" ] && [[ "$2" != -* ]]; then
+				requested_flavor="$2"
+				shift 2
 			else
-				flavor=$2
+				shift
 			fi
-                        echo "Creating the tree with $flavor"
-                        create_kernel_tree
-                        exit;;
-                -d|--delete-tree)
-                        echo "Deleting the tree"
-                        delete_kernel_tree
-			exit;;
+			;;
+		-k|--create-oot)
+			is_oot_tree=1
+			shift
+			;;
+		-o|--override)
+			is_override=1
+			shift
+			;;
+		-d|--delete-tree)
+			action="delete"
+			shift
+			;;
 		-r|--reset-tree)
-			echo "Deleting the existing tree and re-creating it"
-			delete_kernel_tree
-			create_kernel_tree
-			exit;;
-                -h|--help)
-                        usage
-                        ;;
-                *)
-                        echo "Invalid option: $1"
-                        usage
-        esac
+			action="reset"
+			shift
+			;;
+		-h|--help)
+			usage
+			;;
+		--)
+			shift
+			break
+			;;
+		*)
+			echo "Invalid option: $1"
+			usage
+			;;
+	esac
 done
+
+if [ "$is_oot_tree" -eq 1 ]; then
+	flavor="oot"
+elif [ -n "$requested_flavor" ]; then
+	flavor="$requested_flavor"
+fi
+
+case "$action" in
+	create)
+		echo "Creating the tree with $flavor"
+		create_kernel_tree
+		exit
+		;;
+	delete)
+		echo "Deleting the tree"
+		delete_kernel_tree
+		exit
+		;;
+	reset)
+		echo "Deleting the existing tree and re-creating it"
+		delete_kernel_tree
+		create_kernel_tree
+		exit
+		;;
+	*)
+		echo "Invalid option"
+		usage
+		;;
+esac

backport/patches/oot/0001-drm-xe-pf-Handle-VF-BAR-resize-without-PCI-VF-REBAR-.patch

@@ -0,0 +1,131 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
+Date: Thu, 22 Jan 2026 00:00:00 +0000
+Subject: drm/xe/pf: Handle VF BAR resize without PCI VF REBAR helpers
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Implement VF BAR resizing via the VF Resizable BAR capability directly
+in PCI config space for kernels that lack PCI VF REBAR helper APIs.
+
+Suggested-by: Michał Winiarski <michal.winiarski@intel.com>
+Signed-off-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
+---
+ drivers/gpu/drm/xe/xe_pci_sriov.c | 94 +++++++++++++++++++++++++++++--
+ 1 file changed, 90 insertions(+), 4 deletions(-)
+
+diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c
+index 9ff69c484..1246ffc76 100644
+--- a/drivers/gpu/drm/xe/xe_pci_sriov.c
++++ b/drivers/gpu/drm/xe/xe_pci_sriov.c
+@@ -82,16 +82,102 @@ static void pf_engine_activity_stats(struct xe_device *xe, unsigned int num_vfs,
+ 	}
+ }
+ 
++/*
++ * Backport-only fallback: program VF REBAR directly when PCI-core helpers
++ * are not available.
++ */
++
++#ifndef PCI_EXT_CAP_ID_VF_REBAR
++#define PCI_EXT_CAP_ID_VF_REBAR 0x24 /* VF Resizable BAR */
++#endif
++
++static inline resource_size_t pci_rebar_size_to_bytes(int size)
++{
++	return 1ULL << (size + ilog2((resource_size_t)SZ_1M));
++}
++
++/*
++ * The real 'struct pci_sriov' is PCI-core internal (drivers/pci/pci.h).
++ * This local copy is used only to update pdev->sriov->barsz[].
++ */
++struct pci_sriov {
++	int		pos;			/* Capability position */
++	int		nres;			/* Number of resources */
++	u32		cap;			/* SR-IOV Capabilities */
++	u16		ctrl;			/* SR-IOV Control */
++	u16		total_VFs;		/* Total VFs associated with the PF */
++	u16		initial_VFs;		/* Initial VFs associated with the PF */
++	u16		num_VFs;			/* Number of VFs available */
++	u16		offset;			/* First VF Routing ID offset */
++	u16		stride;			/* Following VF stride */
++	u16		vf_device;		/* VF device ID */
++	u32		pgsz;			/* Page size for BAR alignment */
++	u8		link;			/* Function Dependency Link */
++	u8		max_VF_buses;		/* Max buses consumed by VFs */
++	u16		driver_max_VFs;		/* Max num VFs driver supports */
++	struct pci_dev	*dev;			/* Lowest numbered PF */
++	struct pci_dev	*self;			/* This PF */
++	u32		class;			/* VF device */
++	u8		hdr_type;		/* VF header type */
++	u16		subsystem_vendor;	/* VF subsystem vendor */
++	u16		subsystem_device;	/* VF subsystem device */
++	resource_size_t	barsz[PCI_SRIOV_NUM_BARS]; /* VF BAR size */
++	bool		drivers_autoprobe;	/* Auto probing of VFs by driver */
++};
++
+ static int resize_vf_vram_bar(struct xe_device *xe, int num_vfs)
+ {
+ 	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+-	u32 sizes;
++	resource_size_t size, total;
++	int pos, i, vf_bar_idx = VF_LMEM_BAR - PCI_IOV_RESOURCES;
++	u32 rebar, ctrl;
++	int err;
+ 
+-	sizes = pci_iov_vf_bar_get_sizes(pdev, VF_LMEM_BAR, num_vfs);
+-	if (!sizes)
++	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_VF_REBAR);
++	if (!pos)
+ 		return 0;
+ 
+-	return pci_iov_vf_bar_set_size(pdev, VF_LMEM_BAR, __fls(sizes));
++	/* Expecting a single VF resizable BAR, and it to be BAR2. */
++	err = pci_read_config_dword(pdev, pos + PCI_REBAR_CTRL, &ctrl);
++	if (err)
++		return err;
++
++	if (FIELD_GET(PCI_REBAR_CTRL_NBAR_MASK, ctrl) != 1 ||
++	    FIELD_GET(PCI_REBAR_CTRL_BAR_IDX, ctrl) != vf_bar_idx) {
++		xe_sriov_warn(xe, "Unexpected resource in VF resizable BAR, skipping resize\\n");
++		return 0;
++	}
++
++	err = pci_read_config_dword(pdev, pos + PCI_REBAR_CAP, &rebar);
++	if (err)
++		return err;
++
++	rebar = FIELD_GET(PCI_REBAR_CAP_SIZES, rebar);
++	total = pci_resource_len(pdev, VF_LMEM_BAR);
++
++	while (rebar) {
++		i = __fls(rebar);
++		size = pci_rebar_size_to_bytes(i);
++
++		if (num_vfs && size <= div_u64(total, num_vfs)) {
++			ctrl &= ~PCI_REBAR_CTRL_BAR_SIZE;
++			ctrl |= i << PCI_REBAR_CTRL_BAR_SHIFT;
++
++			err = pci_write_config_dword(pdev, pos + PCI_REBAR_CTRL, ctrl);
++			if (err)
++				return err;
++
++			((struct pci_sriov *)pdev->sriov)->barsz[vf_bar_idx] = size;
++
++			xe_sriov_info(xe, "VF BAR%d resized to %llu MiB\\n",
++				      vf_bar_idx, (unsigned long long)(size >> 20));
++			break;
++		}
++
++		rebar &= ~BIT(i);
++	}
++
++	return 0;
+ }
+ 
+ static int pf_prepare_vfs_enabling(struct xe_device *xe)
+-- 
+2.34.1
+