hw/virtio: introduce virtio_device_should_start

The previous fix to virtio_device_started revealed a problem in its
use by both the core and the device code. The core code should be able
to handle the device "starting" while the VM isn't running to handle
the restoration of migration state. To solve this duel use introduce a
new helper for use by the vhost-user backends who all use it to feed a
should_start variable.

We can also pick up a change vhost_user_blk_set_status while we are at
it which follows the same pattern.

Fixes: 9f6bcfd99f (hw/virtio: move vm_running check to virtio_device_started)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Message-Id: <20221107121407.1010913-1-alex.bennee@linaro.org>

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 28409c90f7084974b4e9df5eb23dc897203401ee..16ad4008893a9fee642d00ec10c40a3c63320119 100644 (file)
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -226,14 +226,10 @@ static void vhost_user_blk_stop(VirtIODevice *vdev)
 static void vhost_user_blk_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
     Error *local_err = NULL;
     int ret;
 
-    if (!vdev->vm_running) {
-        should_start = false;
-    }
-
     if (!s->connected) {
         return;
     }

diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
index ad0f91c6070f89ee41faf53f2d226c2842048de6..1c40f420457525b8ffe0aa61193f2b71ccfb2c5f 100644 (file)
--- a/hw/virtio/vhost-user-fs.c
+++ b/hw/virtio/vhost-user-fs.c
@@ -123,7 +123,7 @@ static void vuf_stop(VirtIODevice *vdev)
 static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserFS *fs = VHOST_USER_FS(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
 
     if (vhost_dev_is_started(&fs->vhost_dev) == should_start) {
         return;

diff --git a/hw/virtio/vhost-user-gpio.c b/hw/virtio/vhost-user-gpio.c
index 8b40fe450c22e72dbf0e454f87c5b264a2088114..677d1c77302e8d9d86d23c1e721fa07292801b47 100644 (file)
--- a/hw/virtio/vhost-user-gpio.c
+++ b/hw/virtio/vhost-user-gpio.c
@@ -152,7 +152,7 @@ static void vu_gpio_stop(VirtIODevice *vdev)
 static void vu_gpio_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserGPIO *gpio = VHOST_USER_GPIO(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
 
     trace_virtio_gpio_set_status(status);
 

diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c
index bc58b6c0d126a20a48819e7ea00e7e14d40c72e9..864eba695eb6125c86a168c5f8ab8b365ad2784d 100644 (file)
--- a/hw/virtio/vhost-user-i2c.c
+++ b/hw/virtio/vhost-user-i2c.c
@@ -93,7 +93,7 @@ static void vu_i2c_stop(VirtIODevice *vdev)
 static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
 
     if (vhost_dev_is_started(&i2c->vhost_dev) == should_start) {
         return;

diff --git a/hw/virtio/vhost-user-rng.c b/hw/virtio/vhost-user-rng.c
index bc1f36c5ac34b22dfd56ac571979d74b2126cf51..8b47287875606b5ed9e46739e88a5ef6be5267dd 100644 (file)
--- a/hw/virtio/vhost-user-rng.c
+++ b/hw/virtio/vhost-user-rng.c
@@ -90,7 +90,7 @@ static void vu_rng_stop(VirtIODevice *vdev)
 static void vu_rng_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostUserRNG *rng = VHOST_USER_RNG(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
 
     if (vhost_dev_is_started(&rng->vhost_dev) == should_start) {
         return;

diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c
index 7b67e29d8388c973eac8592382da25368f5d491f..9431b9792cd5c213b52e3daf5e4dfd9bdd044c05 100644 (file)
--- a/hw/virtio/vhost-user-vsock.c
+++ b/hw/virtio/vhost-user-vsock.c
@@ -55,7 +55,7 @@ const VhostDevConfigOps vsock_ops = {
 static void vuv_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
 
     if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) {
         return;

diff --git a/hw/virtio/vhost-vsock.c b/hw/virtio/vhost-vsock.c
index 7dc3c7393122e0ad798ac32fe92cd3249aad8a9e..aa16d584eed391aaa189e31eda7dfa088e81c296 100644 (file)
--- a/hw/virtio/vhost-vsock.c
+++ b/hw/virtio/vhost-vsock.c
@@ -70,7 +70,7 @@ static int vhost_vsock_set_running(VirtIODevice *vdev, int start)
 static void vhost_vsock_set_status(VirtIODevice *vdev, uint8_t status)
 {
     VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
-    bool should_start = virtio_device_started(vdev, status);
+    bool should_start = virtio_device_should_start(vdev, status);
     int ret;
 
     if (vhost_dev_is_started(&vvc->vhost_dev) == should_start) {

diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 1423dba379a3b1da788bc0255a7b6362c77b6e86..141a253a2ce12bb07ef5ee05ff987f82ff7e1b53 100644 (file)
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -395,6 +395,24 @@ static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t status)
         return vdev->started;
     }
 
+    return status & VIRTIO_CONFIG_S_DRIVER_OK;
+}
+
+/**
+ * virtio_device_should_start() - check if device startable
+ * @vdev - the VirtIO device
+ * @status - the devices status bits
+ *
+ * This is similar to virtio_device_started() but also encapsulates a
+ * check on the VM status which would prevent a device starting
+ * anyway.
+ */
+static inline bool virtio_device_should_start(VirtIODevice *vdev, uint8_t status)
+{
+    if (vdev->use_started) {
+        return vdev->started;
+    }
+
     if (!vdev->vm_running) {
         return false;
     }