From ea5d6ea7788c83216547fe72874033d4bf693182 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Tue, 2 Aug 2022 10:49:53 +0100 Subject: [PATCH] include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When debugging a new vhost user you may be surprised to see VHOST_USER_F_PROTOCOL getting squashed in the maze of backend_features, acked_features and guest_features. Expand the description here to help the next poor soul trying to work through this. Signed-off-by: Alex Bennée Message-Id: <20220802095010.3330793-6-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/virtio/virtio.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index db1c0ddf6b..9bb2485415 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -24,7 +24,12 @@ #include "qom/object.h" #include "hw/virtio/vhost.h" -/* A guest should never accept this. It implies negotiation is broken. */ +/* + * A guest should never accept this. It implies negotiation is broken + * between the driver frontend and the device. This bit is re-used for + * vhost-user to advertise VHOST_USER_F_PROTOCOL_FEATURES between QEMU + * and a vhost-user backend. + */ #define VIRTIO_F_BAD_FEATURE 30 #define VIRTIO_LEGACY_FEATURES ((0x1ULL << VIRTIO_F_BAD_FEATURE) | \