[Qemu-devel] [PATCH v2 3/4] contrib/libvhost-user: enable virtio config space messages

[Changpeng Liu]

Enable VHOST_USER_GET_CONFIG/VHOST_USER_SET_CONFIG/VHOST_USER_SET_CONFIG_FD
messages in libvhost-user library, users can implement their own I/O target
based on the library. This enable the virtio config space delivered between
Qemu host device and the I/O target, also event notifier is added in case
of virtio config space changed.

Signed-off-by: Changpeng Liu <address@hidden>
---
 contrib/libvhost-user/libvhost-user.c | 51 +++++++++++++++++++++++++++++++++++
 contrib/libvhost-user/libvhost-user.h | 14 ++++++++++
 2 files changed, 65 insertions(+)

diff --git a/contrib/libvhost-user/libvhost-user.c 
b/contrib/libvhost-user/libvhost-user.c
index 9efb9da..002cf15 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -63,6 +63,9 @@ vu_request_to_string(int req)
         REQ(VHOST_USER_SET_VRING_ENABLE),
         REQ(VHOST_USER_SEND_RARP),
         REQ(VHOST_USER_INPUT_GET_CONFIG),
+        REQ(VHOST_USER_GET_CONFIG),
+        REQ(VHOST_USER_SET_CONFIG),
+        REQ(VHOST_USER_SET_CONFIG_FD),
         REQ(VHOST_USER_MAX),
     };
 #undef REQ
@@ -744,6 +747,43 @@ vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
 }
 
 static bool
+vu_get_config(VuDev *dev, VhostUserMsg *vmsg)
+{
+    if (dev->iface->get_config) {
+        dev->iface->get_config(dev, vmsg->payload.config, vmsg->size);
+    }
+
+    return true;
+}
+
+static bool
+vu_set_config(VuDev *dev, VhostUserMsg *vmsg)
+{
+    if (dev->iface->set_config) {
+        dev->iface->set_config(dev, vmsg->payload.config, vmsg->size);
+    }
+
+    return false;
+}
+
+static bool
+vu_set_config_fd(VuDev *dev, VhostUserMsg *vmsg)
+{
+   if (vmsg->fd_num != 1) {
+        vu_panic(dev, "Invalid config_fd message");
+        return false;
+    }
+
+    if (dev->config_fd != -1) {
+        close(dev->config_fd);
+    }
+    dev->config_fd = vmsg->fds[0];
+    DPRINT("Got config_fd: %d\n", vmsg->fds[0]);
+
+    return false;
+}
+
+static bool
 vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
 {
     int do_reply = 0;
@@ -806,6 +846,12 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
         return vu_get_queue_num_exec(dev, vmsg);
     case VHOST_USER_SET_VRING_ENABLE:
         return vu_set_vring_enable_exec(dev, vmsg);
+    case VHOST_USER_GET_CONFIG:
+        return vu_get_config(dev, vmsg);
+    case VHOST_USER_SET_CONFIG:
+        return vu_set_config(dev, vmsg);
+    case VHOST_USER_SET_CONFIG_FD:
+        return vu_set_config_fd(dev, vmsg);
     default:
         vmsg_close_fds(vmsg);
         vu_panic(dev, "Unhandled request: %d", vmsg->request);
@@ -878,6 +924,10 @@ vu_deinit(VuDev *dev)
 
     vu_close_log(dev);
 
+    if (dev->config_fd != -1) {
+        close(dev->config_fd);
+    }
+
     if (dev->sock != -1) {
         close(dev->sock);
     }
@@ -907,6 +957,7 @@ vu_init(VuDev *dev,
     dev->remove_watch = remove_watch;
     dev->iface = iface;
     dev->log_call_fd = -1;
+    dev->config_fd = -1;
     for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
         dev->vq[i] = (VuVirtq) {
             .call_fd = -1, .kick_fd = -1, .err_fd = -1,
diff --git a/contrib/libvhost-user/libvhost-user.h 
b/contrib/libvhost-user/libvhost-user.h
index 53ef222..899dee1 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -30,6 +30,8 @@
 
 #define VHOST_MEMORY_MAX_NREGIONS 8
 
+#define VHOST_USER_MAX_CONFIG_SIZE 256
+
 enum VhostUserProtocolFeature {
     VHOST_USER_PROTOCOL_F_MQ = 0,
     VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
@@ -62,6 +64,9 @@ typedef enum VhostUserRequest {
     VHOST_USER_SET_VRING_ENABLE = 18,
     VHOST_USER_SEND_RARP = 19,
     VHOST_USER_INPUT_GET_CONFIG = 20,
+    VHOST_USER_GET_CONFIG = 24,
+    VHOST_USER_SET_CONFIG = 25,
+    VHOST_USER_SET_CONFIG_FD = 26,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -105,6 +110,7 @@ typedef struct VhostUserMsg {
         struct vhost_vring_addr addr;
         VhostUserMemory memory;
         VhostUserLog log;
+        uint8_t config[VHOST_USER_MAX_CONFIG_SIZE];
     } payload;
 
     int fds[VHOST_MEMORY_MAX_NREGIONS];
@@ -132,6 +138,9 @@ typedef void (*vu_set_features_cb) (VuDev *dev, uint64_t 
features);
 typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg,
                                   int *do_reply);
 typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool started);
+typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, size_t len);
+typedef int (*vu_set_config_cb) (VuDev *dev, const uint8_t *config,
+                                 size_t len);
 
 typedef struct VuDevIface {
     /* called by VHOST_USER_GET_FEATURES to get the features bitmask */
@@ -148,6 +157,10 @@ typedef struct VuDevIface {
     vu_process_msg_cb process_msg;
     /* tells when queues can be processed */
     vu_queue_set_started_cb queue_set_started;
+    /* get the config space of the device */
+    vu_get_config_cb get_config;
+    /* set the config space of the device */
+    vu_set_config_cb set_config;
 } VuDevIface;
 
 typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx);
@@ -212,6 +225,7 @@ struct VuDev {
     VuDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];
     VuVirtq vq[VHOST_MAX_NR_VIRTQUEUE];
     int log_call_fd;
+    int config_fd;
     uint64_t log_size;
     uint8_t *log_table;
     uint64_t features;
-- 
1.9.3