From d4eb50380807f5e881cbb66630f210e3e6eb9750 Mon Sep 17 00:00:00 2001 From: Hanna Czenczek Date: Mon, 16 Oct 2023 10:32:01 +0200 Subject: [PATCH] vhost-user: Fix protocol feature bit conflict The VHOST_USER_PROTOCOL_F_XEN_MMAP feature bit was defined in f21e95ee97d, which has been part of qemu's 8.1.0 release. However, it seems it was never added to qemu's code, but it is well possible that it is already used by different front-ends outside of qemu (i.e., Xen). VHOST_USER_PROTOCOL_F_SHARED_OBJECT in contrast was added to qemu's code in 16094766627, but never defined in the vhost-user specification. As a consequence, both bits were defined to be 17, which cannot work. Regardless of whether actual code or the specification should take precedence, F_XEN_MMAP is already part of a qemu release, while F_SHARED_OBJECT is not. Therefore, bump the latter to take number 18 instead of 17, and add this to the specification. Take the opportunity to add at least a little note on the VhostUserShared structure to the specification. This structure is referenced by the new commands introduced in 16094766627, but was not defined. Fixes: 160947666276c5b7f6bca4d746bcac2966635d79 ("vhost-user: add shared_object msg") Signed-off-by: Hanna Czenczek Message-Id: <20231016083201.23736-1-hreitz@redhat.com> Reviewed-by: Emmanouil Pitsidianakis Reviewed-by: Stefano Garzarella Reviewed-by: Viresh Kumar Reviewed-by: Stefan Hajnoczi Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/interop/vhost-user.rst | 11 +++++++++++ include/hw/virtio/vhost-user.h | 3 ++- subprojects/libvhost-user/libvhost-user.h | 3 ++- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst index 415bb47a19..768fb5c28c 100644 --- a/docs/interop/vhost-user.rst +++ b/docs/interop/vhost-user.rst @@ -275,6 +275,16 @@ Inflight description :queue size: a 16-bit size of virtqueues +VhostUserShared +^^^^^^^^^^^^^^^ + ++------+ +| UUID | ++------+ + +:UUID: 16 bytes UUID, whose first three components (a 32-bit value, then + two 16-bit values) are stored in big endian. + C structure ----------- @@ -885,6 +895,7 @@ Protocol features #define VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS 15 #define VHOST_USER_PROTOCOL_F_STATUS 16 #define VHOST_USER_PROTOCOL_F_XEN_MMAP 17 + #define VHOST_USER_PROTOCOL_F_SHARED_OBJECT 18 Front-end message types ----------------------- diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h index 6b06ecb1bd..20b69d8e85 100644 --- a/include/hw/virtio/vhost-user.h +++ b/include/hw/virtio/vhost-user.h @@ -29,7 +29,8 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14, VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15, VHOST_USER_PROTOCOL_F_STATUS = 16, - VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 17, + /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ + VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 18, VHOST_USER_PROTOCOL_F_MAX }; diff --git a/subprojects/libvhost-user/libvhost-user.h b/subprojects/libvhost-user/libvhost-user.h index b36a42a7ca..c2352904f0 100644 --- a/subprojects/libvhost-user/libvhost-user.h +++ b/subprojects/libvhost-user/libvhost-user.h @@ -65,7 +65,8 @@ enum VhostUserProtocolFeature { VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14, VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15, /* Feature 16 is reserved for VHOST_USER_PROTOCOL_F_STATUS. */ - VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 17, + /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ + VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 18, VHOST_USER_PROTOCOL_F_MAX };