[Qemu-devel] [PATCH v6 08/12] vhost-user: add vhost_user_input_get_config()

[Marc-André Lureau]

Ask vhost user input backend the list of virtio_input_config.

Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
Reviewed-by: Gerd Hoffmann <kra...@redhat.com>
---
 contrib/libvhost-user/libvhost-user.h |  1 +
 include/hw/virtio/vhost-backend.h     |  4 ++
 hw/virtio/vhost-user.c                | 60 +++++++++++++++++++++++++++
 docs/interop/vhost-user.txt           |  8 ++++
 4 files changed, 73 insertions(+)

diff --git a/contrib/libvhost-user/libvhost-user.h 
b/contrib/libvhost-user/libvhost-user.h
index c0133b7f3f..b0c798fa1a 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -91,6 +91,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_POSTCOPY_ADVISE  = 28,
     VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_POSTCOPY_END     = 30,
+    VHOST_USER_INPUT_GET_CONFIG = 31,
     VHOST_USER_MAX
 } VhostUserRequest;
 
diff --git a/include/hw/virtio/vhost-backend.h 
b/include/hw/virtio/vhost-backend.h
index 81283ec50f..1fca321d8a 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -12,6 +12,7 @@
 #define VHOST_BACKEND_H
 
 #include "exec/memory.h"
+#include "standard-headers/linux/virtio_input.h"
 
 typedef enum VhostBackendType {
     VHOST_BACKEND_TYPE_NONE = 0,
@@ -160,4 +161,7 @@ int vhost_backend_invalidate_device_iotlb(struct vhost_dev 
*dev,
 int vhost_backend_handle_iotlb_msg(struct vhost_dev *dev,
                                           struct vhost_iotlb_msg *imsg);
 
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config);
+
 #endif /* VHOST_BACKEND_H */
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 5df73405bc..cf3fd39035 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -93,6 +93,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_POSTCOPY_ADVISE  = 28,
     VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_POSTCOPY_END     = 30,
+    VHOST_USER_INPUT_GET_CONFIG = 31,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -342,6 +343,65 @@ static int vhost_user_write(struct vhost_dev *dev, 
VhostUserMsg *msg,
     return 0;
 }
 
+static void *vhost_user_read_size(struct vhost_dev *dev, uint32_t size)
+{
+    struct vhost_user *u = dev->opaque;
+    CharBackend *chr = u->user->chr;
+    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 %u.", r, size);
+        g_free(p);
+        return NULL;
+    }
+
+    return p;
+}
+
+int vhost_user_input_get_config(struct vhost_dev *dev,
+                                struct virtio_input_config **config)
+{
+    void *p = NULL;
+    VhostUserMsg msg = {
+        .hdr.request = VHOST_USER_INPUT_GET_CONFIG,
+        .hdr.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;
+    }
+
+    if (msg.hdr.request != VHOST_USER_INPUT_GET_CONFIG) {
+        error_report("Received unexpected msg type. Expected %d received %d",
+                     VHOST_USER_INPUT_GET_CONFIG, msg.hdr.request);
+        goto err;
+    }
+
+    if (msg.hdr.size % sizeof(struct virtio_input_config)) {
+        error_report("Invalid msg size");
+        goto err;
+    }
+
+    p = vhost_user_read_size(dev, msg.hdr.size);
+    if (!p) {
+        goto err;
+    }
+
+    *config = p;
+    return msg.hdr.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/docs/interop/vhost-user.txt b/docs/interop/vhost-user.txt
index 9ee2a60cfb..e145b3ec55 100644
--- a/docs/interop/vhost-user.txt
+++ b/docs/interop/vhost-user.txt
@@ -766,6 +766,14 @@ Master message types
       was previously sent.
       The value returned is an error indication; 0 is success.
 
+ * VHOST_USER_INPUT_GET_CONFIG
+      Id: 31
+      Master payload: N/A
+      Slave payload: (struct virtio_input_config)*
+
+      Ask vhost user input backend the list of virtio_input_config, in
+      host endianness.
+
 Slave message types
 -------------------
 
-- 
2.21.0.4.g36eb1cb9cf