tools/lguest: don't start devices until DRIVER_OK status set.

We were activating them with the virtqueues, and that's not allowed.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 36 insertions, 8 deletions

diff --git a/tools/lguest/lguest.c b/tools/lguest/lguest.c
index 990671e61f87..4c7c2aa66c89 100644
--- a/tools/lguest/lguest.c
+++ b/tools/lguest/lguest.c
@@ -1688,16 +1688,15 @@ static void restore_vq_config(struct virtio_pci_common_cfg *cfg,
 }
 
 /*
+ * 4.1.4.3.2:
+ *
+ *  The driver MUST configure the other virtqueue fields before
+ *  enabling the virtqueue with queue_enable.
+ *
  * When they enable the virtqueue, we check that their setup is valid.
  */
-static void enable_virtqueue(struct device *d, struct virtqueue *vq)
+static void check_virtqueue(struct device *d, struct virtqueue *vq)
 {
-        /*
-         * Create stack for thread.  Since the stack grows upwards, we point
-         * the stack pointer to the end of this region.
-         */
-        char *stack = malloc(32768);
-
         /* Because lguest is 32 bit, all the descriptor high bits must be 0 */
         if (vq->pci_config.queue_desc_hi
             || vq->pci_config.queue_avail_hi
@@ -1716,7 +1715,15 @@ static void enable_virtqueue(struct device *d, struct virtqueue *vq)
                                        sizeof(*vq->vring.used)
                                        + (sizeof(vq->vring.used->ring[0])
                                           * vq->vring.num));
+}
 
+static void start_virtqueue(struct virtqueue *vq)
+{
+        /*
+         * Create stack for thread.  Since the stack grows upwards, we point
+         * the stack pointer to the end of this region.
+         */
+        char *stack = malloc(32768);
 
         /* Create a zero-initialized eventfd. */
         vq->eventfd = eventfd(0, 0);
@@ -1732,6 +1739,16 @@ static void enable_virtqueue(struct device *d, struct virtqueue *vq)
                 err(1, "Creating clone");
 }
 
+static void start_virtqueues(struct device *d)
+{
+        struct virtqueue *vq;
+
+        for (vq = d->vq; vq; vq = vq->next) {
+                if (vq->pci_config.queue_enable)
+                        start_virtqueue(vq);
+        }
+}
+
 static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
 {
         struct virtqueue *vq;
@@ -1780,6 +1797,17 @@ static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
                  */
                 if (val == 0)
                         reset_device(d);
+
+                /*
+                 * 2.1.2:
+                 *
+                 *  The device MUST NOT consume buffers or notify the driver
+                 *  before DRIVER_OK.
+                 */
+                if (val & VIRTIO_CONFIG_S_DRIVER_OK
+                    && !(d->mmio->cfg.device_status & VIRTIO_CONFIG_S_DRIVER_OK))
+                        start_virtqueues(d);
+
                 goto write_through8;
         case offsetof(struct virtio_pci_mmio, cfg.queue_select):
                 vq = vq_by_num(d, val);
@@ -1833,7 +1861,7 @@ static void emulate_mmio_write(struct device *d, u32 off, u32 val, u32 mask)
                  *  The driver MUST configure the other virtqueue fields before
                  *  enabling the virtqueue with queue_enable.
                  */
-                enable_virtqueue(d, vq_by_num(d, d->mmio->cfg.queue_select));
+                check_virtqueue(d, vq_by_num(d, d->mmio->cfg.queue_select));
                 goto write_through16;
         case offsetof(struct virtio_pci_mmio, cfg.queue_notify_off):
                 errx(1, "%s: attempt to write to queue_notify_off", d->name);