On Tue, Aug 29, 2017 at 04:07:59PM -0400, Willem de Bruijn wrote:
From: Willem de Bruijn <willemb@google.com>
Implement a mechanism to signal that a virtio device implements the
VIRTIO_CONFIG_S_NEEDS_RESET command.
Testing for VIRTIO_CONFIG_S_NEEDS_RESET support by issuing the request
and verifying the reset state would require an expensive state change.
To avoid that, add a status bit to the feature register used during
feature negotiation between host and guest.
Set the bit for virtio-net, which supports the feature.
Signed-off-by: Willem de Bruijn <willemb@google.com>
All virtio 1 devices have the reset feature so maybe guest does
not need this flag. Does device need it? Does device really
care that guest can't recover?
quoted hunk ↗ jump to hunk
---
drivers/net/virtio_net.c | 2 ++
include/uapi/linux/virtio_config.h | 3 +++
2 files changed, 5 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 5e349226f7c1..15483a982106 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2801,12 +2801,14 @@ static struct virtio_device_id id_table[] = {
static unsigned int features[] = {
VIRTNET_FEATURES,
+ VIRTIO_F_CAN_RESET,
};
static unsigned int features_legacy[] = {
VIRTNET_FEATURES,
VIRTIO_NET_F_GSO,
VIRTIO_F_ANY_LAYOUT,
+ VIRTIO_F_CAN_RESET,
};
static struct virtio_driver virtio_net_driver = {diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 308e2096291f..726be44a04d3 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -56,6 +56,9 @@
* suppressed them? */
#define VIRTIO_F_NOTIFY_ON_EMPTY 24
+/* Driver supports the VIRTIO_CONFIG_S_NEEDS_RESET command */
+#define VIRTIO_F_CAN_RESET 25
+
/* Can the device handle any descriptor layout? */
#define VIRTIO_F_ANY_LAYOUT 27
#endif /* VIRTIO_CONFIG_NO_LEGACY */
--
2.14.1.342.g6490525c54-goog