Add PCI query port control operation

It is useful for upper layer plugging infrastructure to be able to
query the PCI address given the vhost-user socket path of a specific
relay. This commit implements this query operation via the port control
script and the newly added generic response string in the
PortControlResponse message.

Signed-off-by: Heinrich Kuhn <[email protected]>
Signed-off-by: Simon Horman <[email protected]>

scripts/python2/virtioforwarder_port_control.py

@@ -50,13 +50,14 @@ def _syntax():
     parser = argparse.ArgumentParser()
     parser.add_argument(
         'op', metavar='OP',
-        choices=('add', 'remove', 'add_sock', 'remove_sock'),
+        choices=('add', 'remove', 'add_sock', 'remove_sock', 'query_pci'),
         help='port control operation',
     )
     parser.add_argument(
         '--vhost-path', type=str,
         help='Path to vhostuser socket.'
              ' Use this option with the add/remove-sock operations'
+             ' or when querying the associated PCI device'
     )
     parser.add_argument(
         '--virtio-id', metavar='virtio-id', type=int,

scripts/python3/virtioforwarder_port_control.py

@@ -50,13 +50,14 @@ def _syntax():
     parser = argparse.ArgumentParser()
     parser.add_argument(
         'op', metavar='OP',
-        choices=('add', 'remove', 'add_sock', 'remove_sock'),
+        choices=('add', 'remove', 'add_sock', 'remove_sock', 'query_pci'),
         help='port control operation',
     )
     parser.add_argument(
         '--vhost-path', type=str,
         help='Path to vhostuser socket.'
              ' Use this option with the add/remove-sock operations'
+             ' or when querying the associated PCI device'
     )
     parser.add_argument(
         '--virtio-id', metavar='virtio-id', type=int,

virtio_vhostuser.c

@@ -39,6 +39,7 @@
 #include <stdbool.h>
 #include <bsd/string.h>
 #include "virtio_vhostuser.h"
+#include "virtioforwarder.pb-c.h"
 #define __MODULE__ "virtio_vhostuser"
 #include "log.h"
 #include "virtio_worker.h"
@@ -801,6 +802,46 @@ int virtio_add_sock_dev_pair(const char *vhost_path,
 	return 5;
 }
 
+int virtio_query_pci(Virtioforwarder__PortControlResponse *response,
+		     const char *vhost_path)
+{
+	int relay_id = -1;
+	vio_vf_relay_t *relay;
+
+	if (!vhost_path) {
+		// This should never happen because the zmq logic checks for
+		// this case too
+		log_error("vhost path not passed to virtio_query_pci");
+		return EINVAL;
+	}
+
+	relay_id = get_relay_for_sock(vhost_path);
+
+	if (relay_id < 0) {
+		log_error("Could not find relay associated with %s",
+			vhost_path);
+		return ENOENT;
+	}
+
+	log_debug("query PCI for relay number: %d", relay_id);
+
+	relay = get_relay_from_id(relay_id);
+	if (relay == NULL) {
+		// This shouldn't happen but gaurd against it here anyway
+		log_error("Could not find relay instance with ID: %d",
+			relay_id);
+		return ENOENT;
+	}
+
+	log_debug("Got virtio_query_pci(*response, %s)", vhost_path);
+
+	// Just set the query_string pointer to the pci_dbdf pointer in the
+	// relay struct
+	response->query_string = relay->dpdk.pci_dbdf;
+
+	return 0;
+}
+
 int virtio_remove_sock_dev_pair(const char *vhost_path, char *dev,
 			bool conditional)
 {

virtio_vhostuser.h

@@ -39,6 +39,8 @@
 #include <rte_eal.h>
 #include <rte_ethdev.h>
 
+#include "virtioforwarder.pb-c.h"
+
 #define MAX_RELAYS RTE_MAX_ETHPORTS
 #define MAX_NUM_BOND_SLAVES 8
 
@@ -82,5 +84,7 @@ int virtio_add_sock_dev_pair(const char *vhost_path,
 			bool conditional);
 int virtio_remove_sock_dev_pair(const char *vhost_path, char *dev,
 			bool conditional);
+int virtio_query_pci(Virtioforwarder__PortControlResponse *response,
+		     const char *vhost_path);
 
 #endif // _VIRTIO_VHOSTUSER_THREAD

virtioforwarder.proto

@@ -41,6 +41,7 @@ message PortControlRequest {
         REMOVE = 1;
         ADD_SOCK = 2;
         REMOVE_SOCK = 3;
+        QUERY_PCI = 4;
     }
 
     required Op op = 1;

zmq_port_control.c

@@ -150,6 +150,12 @@ validate_PortControlRequest(Virtioforwarder__PortControlRequest const *pc)
 			log_warning("The virtio id will be ignored for socket pair operations.");
 	}
 
+	if (pc->op == VIRTIOFORWARDER__PORT_CONTROL_REQUEST__OP__QUERY_PCI &&
+			pc->vhost_path == NULL) {
+		log_error("PCI query requires a vhost-user socket path");
+		return false;
+	}
+
 	return true;
 }
 
@@ -204,6 +210,19 @@ port_control_handle_remove_socket(Virtioforwarder__PortControlResponse *response
 	);
 }
 
+static void
+port_control_handle_query_pci(Virtioforwarder__PortControlResponse *response,
+			struct port_control_req_buffer *cfg)
+{
+	printf("In handle_query_pci");
+	handle_PortControlRequest_set_error_code(
+		response, "virtio_query_pci()",
+		virtio_query_pci(
+			response, cfg->vhost_path
+		)
+	);
+}
+
 static void
 port_control_handle_add(Virtioforwarder__PortControlResponse *response,
 			struct port_control_req_buffer *cfg,
@@ -335,6 +354,10 @@ handle_PortControlRequest(
 						pc->name, conditional);
 			break;
 
+		case VIRTIOFORWARDER__PORT_CONTROL_REQUEST__OP__QUERY_PCI:
+			port_control_handle_query_pci(&response, &b);
+			break;
+
 		default:
 			log_critical("unhandled PortControlRequest.Op %i", pc->op);
 			break;