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Thu, 13 Aug 2020 05:49:32 -0400 (EDT) Received: by x220.qyliss.net (Postfix, from userid 1000) id 98D741E1; Thu, 13 Aug 2020 09:49:30 +0000 (UTC) From: Alyssa Ross To: qemu-devel@nongnu.org Subject: [PATCH] docs: clarify absence of set_features in vhost-user Date: Thu, 13 Aug 2020 09:48:48 +0000 Message-Id: <20200813094847.4288-1-hi@alyssa.is> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Received-SPF: softfail client-ip=64.147.123.19; envelope-from=qyliss@x220.qyliss.net; helo=wout3-smtp.messagingengine.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/13 05:51:55 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-0.001, SPF_SOFTFAIL=0.665, URIBL_BLOCKED=0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S . Tsirkin" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" The previous wording was (at least to me) ambiguous about whether a backend should enable features immediately after they were set using VHOST_USER_SET_PROTOCOL_FEATURES, or wait for support for protocol features to be acknowledged if it hasn't been yet before enabling those features. This patch attempts to make it clearer that VHOST_USER_SET_PROTOCOL_FEATURES should immediately enable features, even if support for protocol features has not yet been acknowledged, while still also making clear that the frontend SHOULD acknowledge support for protocol features. Previous discussion begins here: Cc: Michael S. Tsirkin Signed-off-by: Alyssa Ross --- docs/interop/vhost-user.rst | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 10e3e3475e..bc78c9947f 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -854,9 +854,9 @@ Master message types ``VHOST_USER_GET_FEATURES``. .. Note:: - Slave that reported ``VHOST_USER_F_PROTOCOL_FEATURES`` must - support this message even before ``VHOST_USER_SET_FEATURES`` was - called. + While QEMU should acknowledge ``VHOST_USER_F_PROTOCOL_FEATURES``, a + backend must allow ``VHOST_USER_GET_PROTOCOL_FEATURES`` even if + ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been acknowledged yet. ``VHOST_USER_SET_PROTOCOL_FEATURES`` :id: 16 @@ -869,8 +869,12 @@ Master message types ``VHOST_USER_GET_FEATURES``. .. Note:: - Slave that reported ``VHOST_USER_F_PROTOCOL_FEATURES`` must support - this message even before ``VHOST_USER_SET_FEATURES`` was called. + While QEMU should acknowledge ``VHOST_USER_F_PROTOCOL_FEATURES``, a + backend must allow ``VHOST_USER_SET_PROTOCOL_FEATURES`` even if + ``VHOST_USER_F_PROTOCOL_FEATURES`` has not been acknowledged yet. + The backend must not wait for ``VHOST_USER_SET_FEATURES`` before + enabling protocol features requested with + ``VHOST_USER_SET_PROTOCOL_FEATURES``. ``VHOST_USER_SET_OWNER`` :id: 3