[Qemu-devel] [RFC 04/14] vhost-user: add vhost_user_input_get_config()

[marcandre . lureau]

From: Marc-André Lureau <marcandre.lur...@redhat.com>

Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
---
 docs/specs/vhost-user.txt         |  9 ++++++
 hw/virtio/vhost-user.c            | 58 +++++++++++++++++++++++++++++++++++++++
 include/hw/virtio/vhost-backend.h |  4 +++
 3 files changed, 71 insertions(+)

diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
index 777c49c..fab67a5 100644
--- a/docs/specs/vhost-user.txt
+++ b/docs/specs/vhost-user.txt
@@ -464,3 +464,12 @@ Message types
       is present in VHOST_USER_GET_PROTOCOL_FEATURES.
       The first 6 bytes of the payload contain the mac address of the guest to
       allow the vhost user backend to construct and broadcast the fake RARP.
+
+ * VHOST_USER_INPUT_GET_CONFIG
+
+      Id: 20
+      Equivalent ioctl: N/A
+      Master payload: N/A
+      Slave payload: (struct virtio_input_config)*
+
+      Ask vhost user input backend the list of virtio_input_config.
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 63ffe48..8072c16 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -58,6 +58,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_GET_QUEUE_NUM = 17,
     VHOST_USER_SET_VRING_ENABLE = 18,
     VHOST_USER_SEND_RARP = 19,
+    VHOST_USER_INPUT_GET_CONFIG = 20,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -205,6 +206,63 @@ static int vhost_user_write(struct vhost_dev *dev, 
VhostUserMsg *msg,
             0 : -1;
 }
 
+static void *vhost_user_read_size(struct vhost_dev *dev, uint32_t size)
+{
+    CharDriverState *chr = dev->opaque;
+    int r;
+    uint8_t *p = g_malloc(size);
+
+    r = qemu_chr_fe_read_all(chr, p, size);
+    if (r != size) {
+        error_report("Failed to read msg payload."
+                     " Read %d instead of %d.", r, size);
+        return NULL;
+    }
+
+    return p;
+}
+
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config)
+{
+    void *p = NULL;
+    VhostUserMsg msg = {
+        .request = VHOST_USER_INPUT_GET_CONFIG,
+        .flags = VHOST_USER_VERSION,
+    };
+
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        goto err;
+    }
+
+    if (vhost_user_read_header(dev, &msg) < 0) {
+        goto err;
+    }
+
+    p = vhost_user_read_size(dev, msg.size);
+    if (!p) {
+        goto err;
+    }
+
+    if (msg.request != VHOST_USER_INPUT_GET_CONFIG) {
+        error_report("Received unexpected msg type. Expected %d received %d",
+                     VHOST_USER_INPUT_GET_CONFIG, msg.request);
+        goto err;
+    }
+
+    if (msg.size % sizeof(struct virtio_input_config)) {
+        error_report("Invalid msg size");
+        goto err;
+    }
+
+    *config = p;
+    return msg.size / sizeof(struct virtio_input_config);
+
+err:
+    g_free(p);
+    return -1;
+}
+
 static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
                                    struct vhost_log *log)
 {
diff --git a/include/hw/virtio/vhost-backend.h 
b/include/hw/virtio/vhost-backend.h
index 95fcc96..08d34db 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -11,6 +11,7 @@
 #ifndef VHOST_BACKEND_H_
 #define VHOST_BACKEND_H_
 
+#include "standard-headers/linux/virtio_input.h"
 
 typedef enum VhostBackendType {
     VHOST_BACKEND_TYPE_NONE = 0,
@@ -107,4 +108,7 @@ extern const VhostOps user_ops;
 int vhost_set_backend_type(struct vhost_dev *dev,
                            VhostBackendType backend_type);
 
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config);
+
 #endif /* VHOST_BACKEND_H_ */
-- 
2.7.4