scripts: refactor prepare_vdpa for distro-specific setup

Split the vDPA preparation flow into helper functions for
building modules, validating availability, loading modules,
and creating devices.

Build the vdpa_sim modules only on Ubuntu, where the script
installs dependencies and compiles them from the matching
kernel source. On other distributions, reuse the installed
kernel modules and verify that they are available before
continuing.

This makes the script easier to follow and supports systems
such as Azure Linux, where the modules are provided by the
kernel package.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

scripts/prepare_vdpa.sh

@@ -1,35 +1,73 @@
 #!/usr/bin/env bash
 set -x
 
-sudo apt install -y libncurses-dev gawk flex bison openssl libssl-dev dkms libelf-dev libudev-dev libpci-dev libiberty-dev autoconf git make dpkg-dev libmnl-dev pkg-config iproute2
-sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
-sudo apt update
-apt-get source linux-image-unsigned-"$(uname -r)"
-pushd linux-azure*/drivers/vdpa/vdpa_sim/ || exit
-# REUSE-IgnoreStart
-cat <<'EOF' >Makefile
+build_install_vdpa_sim_modules_ubuntu() {
+    sudo apt install -y libncurses-dev gawk flex bison openssl libssl-dev dkms libelf-dev libudev-dev libpci-dev libiberty-dev autoconf git make dpkg-dev libmnl-dev pkg-config iproute2
+    sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
+    sudo apt update
+    apt-get source linux-image-unsigned-"$(uname -r)"
+    pushd linux-azure*/drivers/vdpa/vdpa_sim/ || exit
+    # REUSE-IgnoreStart
+    cat <<'EOF' >Makefile
 # SPDX-License-Identifier: GPL-2.0
 obj-m += vdpa_sim.o
 obj-m += vdpa_sim_net.o
 obj-m += vdpa_sim_blk.o
 EOF
-# REUSE-IgnoreEnd
-make -C /lib/modules/"$(uname -r)"/build M="$PWD"
-sudo make -C /lib/modules/"$(uname -r)"/build M="$PWD" modules_install
-popd || exit
-sudo depmod -a
-sudo modprobe vdpa
-sudo modprobe vhost_vdpa
-sudo modprobe vdpa_sim
-sudo modprobe vdpa_sim_blk
-sudo modprobe vdpa_sim_net
-# Create /dev/vhost-vdpa-0
-sudo vdpa dev add name vdpa-blk1 mgmtdev vdpasim_blk
-# Create /dev/vhost-vdpa-1
-sudo vdpa dev add name vdpa-blk2 mgmtdev vdpasim_blk
-# Create /dev/vhost-vdpa-2
-sudo vdpa dev add name vdpa-net1 mgmtdev vdpasim_net
-sudo chmod 660 /dev/vhost-vdpa-0
-sudo chmod 660 /dev/vhost-vdpa-1
-sudo chmod 660 /dev/vhost-vdpa-2
-vdpa dev show -jp
+    # REUSE-IgnoreEnd
+    make -C /lib/modules/"$(uname -r)"/build M="$PWD"
+    sudo make -C /lib/modules/"$(uname -r)"/build M="$PWD" modules_install
+    popd || exit
+    sudo depmod -a
+}
+
+check_vdpa_sim_modules() {
+    for module in $MODULES; do
+        modinfo "$module" || {
+            echo "Module $module is not installed. Please build and install it first."
+            exit 1
+        }
+    done
+}
+
+modproobe_modules() {
+    for module in $MODULES; do
+        sudo modprobe "$module" || {
+            echo "Failed to load module $module. Please check if it is installed correctly."
+            exit 1
+        }
+    done
+}
+
+prepare_vdpa() {
+    # Create /dev/vhost-vdpa-0
+    sudo vdpa dev add name vdpa-blk1 mgmtdev vdpasim_blk
+    # Create /dev/vhost-vdpa-1
+    sudo vdpa dev add name vdpa-blk2 mgmtdev vdpasim_blk
+    # Create /dev/vhost-vdpa-2
+    sudo vdpa dev add name vdpa-net1 mgmtdev vdpasim_net
+    sudo chmod 660 /dev/vhost-vdpa-0
+    sudo chmod 660 /dev/vhost-vdpa-1
+    sudo chmod 660 /dev/vhost-vdpa-2
+    vdpa dev show -jp
+}
+
+MODULES="vdpa vhost_vdpa vdpa_sim vdpa_sim_blk vdpa_sim_net"
+DISTRO_NAME="ubuntu"
+if [[ -f /etc/lsb-release ]]; then
+    DISTRO_NAME=$(grep DISTRIB_ID /etc/lsb-release | cut -d '=' -f 2)
+    # Converts the value of the DISTRO_NAME variable to lowercase letters.
+    DISTRO_NAME=$(echo "$DISTRO_NAME" | tr '[:upper:]' '[:lower:]')
+    echo "Distribution Name: $DISTRO_NAME"
+fi
+
+if [[ "$DISTRO_NAME" == "ubuntu" ]]; then
+    build_install_vdpa_sim_modules_ubuntu
+fi
+# For other distros, we assume the modules are already built and installed
+# For Azure Linux, the modules are included in the kernel and should be available by default
+check_vdpa_sim_modules
+
+modproobe_modules
+
+prepare_vdpa