From: Alex Bennée Date: Tue, 2 Aug 2022 09:49:53 +0000 (+0100) Subject: include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ea5d6ea7788c83216547fe72874033d4bf693182;p=qemu.git include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE 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 --- 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) | \