T7757: VPP Verify buffers for rx/tx queues

4 files changed, 58 insertions, 10 deletions

diff --git a/interface-definitions/vpp.xml.in b/interface-definitions/vpp.xml.in
index f69e05168..356345f84 100644
--- a/interface-definitions/vpp.xml.in
+++ b/interface-definitions/vpp.xml.in
@@ -367,6 +367,7 @@
                     <validator name="numeric" argument="--range 0-4294967295"/>
                   </constraint>
                 </properties>
+                <defaultValue>16384</defaultValue>
               </leafNode>
               <leafNode name="data-size">
                 <properties>
@@ -379,12 +380,14 @@
                     <validator name="numeric" argument="--range 0-4294967295"/>
                   </constraint>
                 </properties>
+                <defaultValue>2048</defaultValue>
               </leafNode>
               <leafNode name="page-size">
                 <properties>
                   <help>Set the page-size for buffer allocation</help>
                   #include <include/unformat_log2_page_size.xml.i>
                 </properties>
+                <defaultValue>default</defaultValue>
               </leafNode>
             </children>
           </node>
@@ -501,6 +504,7 @@
                         <validator name="numeric" argument="--range 256-8192"/>
                       </constraint>
                     </properties>
+                    <defaultValue>1024</defaultValue>
                   </leafNode>
                   <leafNode name="num-tx-desc">
                     <properties>
@@ -513,6 +517,7 @@
                         <validator name="numeric" argument="--range 256-8192"/>
                       </constraint>
                     </properties>
+                    <defaultValue>1024</defaultValue>
                   </leafNode>
                   <leafNode name="num-rx-queues">
                     <properties>
diff --git a/python/vyos/vpp/config_resource_checks/memory.py b/python/vyos/vpp/config_resource_checks/memory.py
index 9391e21e1..8b201ef87 100644
--- a/python/vyos/vpp/config_resource_checks/memory.py
+++ b/python/vyos/vpp/config_resource_checks/memory.py
@@ -28,6 +28,10 @@ from vyos.vpp.utils import (
 from vyos.vpp.config_resource_checks.resource_defaults import default_resource_map
 
 
+# VPP buffers default per NUMA node
+MIN_BUFFERS = 16_384
+
+
 def classify_page_size(page_size_bytes: int) -> str:
     """
     Returns one of: '4K', '2M', '1G' based on page size.
@@ -187,3 +191,33 @@ def total_memory_required(settings: dict) -> dict:
         memory[classify_page_size(page_size)] += memory_size
 
     return memory
+
+
+def buffers_required(settings: dict, workers) -> int:
+    """
+    Calculate total VPP buffer requirements based on interface settings and workers.
+    """
+    buffers_total = 0
+    for ifname, iface_config in settings.get('interface', {}).items():
+        if iface_config.get('driver') == 'xdp':
+            continue
+        dpdk_options = iface_config.get('dpdk_options', {})
+        rx_queues = int(dpdk_options.get('num_rx_queues', 1))
+        rx_desc = int(dpdk_options.get('num_rx_desc'))
+        tx_queues = int(dpdk_options.get('num_tx_queues', workers + 1))
+        tx_desc = int(dpdk_options.get('num_tx_desc'))
+
+        # buffers for RX/TX queues for interface
+        buffers_total += rx_queues * rx_desc + tx_queues * tx_desc
+
+    # per-thread buffer caches (approx. 256 buffers per worker)
+    buffers_total += workers * 256
+
+    # Safety margin for buffer calculations:
+    # traffic bursts, alignment/metadata overhead etc.
+    # The factor 2.5 is derived from VPP’s own calculations:
+    # https://github.com/FDio/vpp/blob/stable/2506/extras/vpp_config/vpplib/AutoConfig.py#L609
+    buffers_total = int(buffers_total * 2.5)
+
+    # Enforce minimum required by VPP (16K buffers)
+    return max(buffers_total, MIN_BUFFERS)
diff --git a/python/vyos/vpp/config_verify.py b/python/vyos/vpp/config_verify.py
index cf0b923bb..78c5d420b 100644
--- a/python/vyos/vpp/config_verify.py
+++ b/python/vyos/vpp/config_verify.py
@@ -442,3 +442,15 @@ def verify_routes_count(settings: dict, workers: int):
         'Extensive use of features like ACLs, NAT and others may reduce the numbers above. '
         'Please read the documentation for details: https://docs.vyos.io/'
     )
+
+
+def verify_vpp_buffers(settings: dict, workers: int):
+    buffers_configured = int(settings['buffers']['buffers_per_numa'])
+
+    buffers_required = mem_checks.buffers_required(settings, workers)
+
+    if buffers_required > buffers_configured:
+        raise ConfigError(
+            'Not enough buffers to initialize RX/TX queues for interfaces. '
+            f'Set "vpp settings buffers buffers-per-numa" to {buffers_required} or higher'
+        )
diff --git a/src/conf_mode/vpp.py b/src/conf_mode/vpp.py
index 9517f85f3..b205291f2 100755
--- a/src/conf_mode/vpp.py
+++ b/src/conf_mode/vpp.py
@@ -58,6 +58,7 @@ from vyos.vpp.config_verify import (
     verify_vpp_interfaces_dpdk_num_queues,
     verify_routes_count,
     verify_vpp_main_heap_size,
+    verify_vpp_buffers,
 )
 from vyos.vpp.config_filter import iface_filter_eth
 from vyos.vpp.utils import EthtoolGDrvinfo
@@ -223,10 +224,12 @@ def get_config(config=None):
     # dictionary retrieved.
     default_values = conf.get_config_defaults(**config.kwargs, recursive=True)
 
-    # delete 'xdp-options' from defaults if driver is DPDK
+    # delete driver-incompatible defaults
     for iface, iface_config in config.get('settings', {}).get('interface', {}).items():
         if iface_config.get('driver') == 'dpdk':
             del default_values['settings']['interface'][iface]['xdp_options']
+        elif iface_config.get('driver') == 'xdp':
+            del default_values['settings']['interface'][iface]['dpdk_options']
 
     config = config_dict_merge(default_values, config)
 
@@ -342,15 +345,6 @@ def get_config(config=None):
             eth_ifaces_persist[iface]['bus_id'] = control_host.get_bus_name(iface)
             eth_ifaces_persist[iface]['dev_id'] = control_host.get_dev_id(iface)
 
-    # Get kernel settings for hugepages
-    kernel_memory_settings = conf.get_config_dict(
-        ['system', 'option', 'kernel', 'memory'],
-        key_mangling=('-', '_'),
-        get_first_key=True,
-        no_tag_node_value_mangle=True,
-    )
-    config['kernel_memory_settings'] = kernel_memory_settings
-
     # Return to config dictionary
     config['persist_config'] = eth_ifaces_persist
 
@@ -411,6 +405,9 @@ def verify(config):
     verify_vpp_main_heap_size(config['settings'])
     verify_vpp_statseg_size(config['settings'])
 
+    # Check buffers
+    verify_vpp_buffers(config['settings'], workers)
+
     # Check if available memory is enough for current VPP config
     verify_vpp_memory(config)