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[PATCH v2 02/15] include/hw/virtio: more comment for VIRTIO_F_BAD_FEATUR
From: |
Alex Bennée |
Subject: |
[PATCH v2 02/15] include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE |
Date: |
Tue, 24 May 2022 16:40:43 +0100 |
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 <alex.bennee@linaro.org>
---
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..2b2587d324 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 to advertise VHOST_USER_F_PROTOCOL_FEATURES
+ * between QEMU and a vhost backend.
+ */
#define VIRTIO_F_BAD_FEATURE 30
#define VIRTIO_LEGACY_FEATURES ((0x1ULL << VIRTIO_F_BAD_FEATURE) | \
--
2.30.2
- [PATCH v2 00/15] virtio-gpio and various virtio cleanups, Alex Bennée, 2022/05/24
- [PATCH v2 03/15] include/hw/virtio: document vhost_get_features, Alex Bennée, 2022/05/24
- [PATCH v2 08/15] tests/qtest: add a timeout for subprocess_run_one_test, Alex Bennée, 2022/05/24
- [PATCH v2 02/15] include/hw/virtio: more comment for VIRTIO_F_BAD_FEATURE,
Alex Bennée <=
- [PATCH v2 01/15] contrib/vhost-user-blk: fix 32 bit build and enable, Alex Bennée, 2022/05/24
- [PATCH v2 06/15] hw/virtio: add vhost-user-gpio-pci boilerplate, Alex Bennée, 2022/05/24
- [PATCH v2 07/15] tests/qtest: pass stdout/stderr down to subtests, Alex Bennée, 2022/05/24
- [PATCH v2 05/15] hw/virtio: add boilerplate for vhost-user-gpio device, Alex Bennée, 2022/05/24
- [PATCH v2 11/15] tests/qtest: use g_autofree for test_server_create_chr, Alex Bennée, 2022/05/24
- [PATCH v2 10/15] tests/qtest: catch unhandled vhost-user messages, Alex Bennée, 2022/05/24