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2023-11-07vhost-user.rst: Migrating back-end-internal stateHanna Czenczek1-0/+172
For vhost-user devices, qemu can migrate the virtio state, but not the back-end's internal state. To do so, we need to be able to transfer this internal state between front-end (qemu) and back-end. At this point, this new feature is added for the purpose of virtio-fs migration. Because virtiofsd's internal state will not be too large, we believe it is best to transfer it as a single binary blob after the streaming phase. These are the additions to the protocol: - New vhost-user protocol feature VHOST_USER_PROTOCOL_F_DEVICE_STATE - SET_DEVICE_STATE_FD function: Front-end and back-end negotiate a file descriptor over which to transfer the state. - CHECK_DEVICE_STATE: After the state has been transferred through the file descriptor, the front-end invokes this function to verify success. There is no in-band way (through the file descriptor) to indicate failure, so we need to check explicitly. Once the transfer FD has been established via SET_DEVICE_STATE_FD (which includes establishing the direction of transfer and migration phase), the sending side writes its data into it, and the reading side reads it until it sees an EOF. Then, the front-end will check for success via CHECK_DEVICE_STATE, which on the destination side includes checking for integrity (i.e. errors during deserialization). Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20231016134243.68248-5-hreitz@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-11-07vhost-user.rst: Introduce suspended stateHanna Czenczek1-1/+19
In vDPA, GET_VRING_BASE does not stop the queried vring, which is why SUSPEND was introduced so that the returned index would be stable. In vhost-user, it does stop the vring, so under the same reasoning, it can get away without SUSPEND. Still, we do want to clarify that if the device is completely stopped, i.e. all vrings are stopped, the back-end should cease to modify any state relating to the guest. Do this by calling it "suspended". Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20231016134243.68248-4-hreitz@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-11-07vhost-user.rst: Clarify enabling/disabling vringsHanna Czenczek1-15/+17
Currently, the vhost-user documentation says that rings are to be initialized in a disabled state when VHOST_USER_F_PROTOCOL_FEATURES is negotiated. However, by the time of feature negotiation, all rings have already been initialized, so it is not entirely clear what this means. At least the vhost-user-backend Rust crate's implementation interpreted it to mean that whenever this feature is negotiated, all rings are to put into a disabled state, which means that every SET_FEATURES call would disable all rings, effectively halting the device. This is problematic because the VHOST_F_LOG_ALL feature is also set or cleared this way, which happens during migration. Doing so should not halt the device. Other implementations have interpreted this to mean that the device is to be initialized with all rings disabled, and a subsequent SET_FEATURES call that does not set VHOST_USER_F_PROTOCOL_FEATURES will enable all of them. Here, SET_FEATURES will never disable any ring. This interpretation does not suffer the problem of unintentionally halting the device whenever features are set or cleared, so it seems better and more reasonable. We can clarify this in the documentation by making it explicit that the enabled/disabled state is tracked even while the vring is stopped. Every vring is initialized in a disabled state, and SET_FEATURES without VHOST_USER_F_PROTOCOL_FEATURES simply becomes one way to enable all vrings. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20231016134243.68248-3-hreitz@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-11-07vhost-user.rst: Improve [GS]ET_VRING_BASE docHanna Czenczek1-4/+73
GET_VRING_BASE does not mention that it stops the respective ring. Fix that. Furthermore, it is not fully clear what the "base offset" these commands' documentation refers to is; an offset could be many things. Be more precise and verbose about it, especially given that these commands use different payload structures depending on whether the vring is split or packed. Signed-off-by: Hanna Czenczek <hreitz@redhat.com> Message-Id: <20231016134243.68248-2-hreitz@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-10-22vhost-user: Fix protocol feature bit conflictHanna Czenczek1-0/+11
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 <hreitz@redhat.com> Message-Id: <20231016083201.23736-1-hreitz@redhat.com> Reviewed-by: Emmanouil Pitsidianakis <manos.pitsidianakis@linaro.org> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-10-05nbd/server: Add FLAG_PAYLOAD support to CMD_BLOCK_STATUSEric Blake1-1/+1
Allow a client to request a subset of negotiated meta contexts. For example, a client may ask to use a single connection to learn about both block status and dirty bitmaps, but where the dirty bitmap queries only need to be performed on a subset of the disk; forcing the server to compute that information on block status queries in the rest of the disk is wasted effort (both at the server, and on the amount of traffic sent over the wire to be parsed and ignored by the client). Qemu as an NBD client never requests to use more than one meta context, so it has no need to use block status payloads. Testing this instead requires support from libnbd, which CAN access multiple meta contexts in parallel from a single NBD connection; an interop test submitted to the libnbd project at the same time as this patch demonstrates the feature working, as well as testing some corner cases (for example, when the payload length is longer than the export length), although other corner cases (like passing the same id duplicated) requires a protocol fuzzer because libnbd is not wired up to break the protocol that badly. This also includes tweaks to 'qemu-nbd --list' to show when a server is advertising the capability, and to the testsuite to reflect the addition to that output. Of note: qemu will always advertise the new feature bit during NBD_OPT_INFO if extended headers have alreay been negotiated (regardless of whether any NBD_OPT_SET_META_CONTEXT negotiation has occurred); but for NBD_OPT_GO, qemu only advertises the feature if block status is also enabled (that is, if the client does not negotiate any contexts, then NBD_CMD_BLOCK_STATUS cannot be used, so the feature is not advertised). Signed-off-by: Eric Blake <eblake@redhat.com> Message-ID: <20230925192229.3186470-26-eblake@redhat.com> [eblake: fix logic to reject unnegotiated contexts] Signed-off-by: Eric Blake <eblake@redhat.com>
2023-10-05nbd/server: Enable initial support for extended headersEric Blake1-0/+1
Time to start supporting clients that request extended headers. Now we can finally reach the code added across several previous patches. Even though the NBD spec has been altered to allow us to accept NBD_CMD_READ larger than the max payload size (provided our response is a hole or broken up over more than one data chunk), we are not planning to take advantage of that, and continue to cap NBD_CMD_READ to 32M regardless of header size. For NBD_CMD_WRITE_ZEROES and NBD_CMD_TRIM, the block layer already supports 64-bit operations without any effort on our part. For NBD_CMD_BLOCK_STATUS, the client's length is a hint, and the previous patch took care of implementing the required NBD_REPLY_TYPE_BLOCK_STATUS_EXT. We do not yet support clients that want to do request payload filtering of NBD_CMD_BLOCK_STATUS; that will be added in later patches, but is not essential for qemu as a client since qemu only requests the single context base:allocation. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-ID: <20230925192229.3186470-19-eblake@redhat.com>
2023-10-04vhost-user: add shared_object msgAlbert Esteve1-0/+57
Add three new vhost-user protocol `VHOST_USER_BACKEND_SHARED_OBJECT_* messages`. These new messages are sent from vhost-user back-ends to interact with the virtio-dmabuf table in order to add or remove themselves as virtio exporters, or lookup for virtio dma-buf shared objects. The action taken in the front-end depends on the type stored in the virtio shared object hash table. When the table holds a pointer to a vhost backend for a given UUID, the front-end sends a VHOST_USER_GET_SHARED_OBJECT to the backend holding the shared object. The messages can only be sent after successfully negotiating a new VHOST_USER_PROTOCOL_F_SHARED_OBJECT vhost-user protocol feature bit. Finally, refactor code to send response message so that all common parts both for the common REPLY_ACK case, and other data responses, can call it and avoid code repetition. Signed-off-by: Albert Esteve <aesteve@redhat.com> Message-Id: <20231002065706.94707-4-aesteve@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-09-12docs: vhost-user-gpu: add protocol changes for dmabuf modifiersErico Nunes1-1/+25
VHOST_USER_GPU_DMABUF_SCANOUT2 is defined as a message with all the contents of VHOST_USER_GPU_DMABUF_SCANOUT plus the dmabuf modifiers which were ommitted. The VHOST_USER_GPU_PROTOCOL_F_DMABUF2 protocol feature is defined as a way to check whether this new message is supported or not. Signed-off-by: Erico Nunes <ernunes@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Sergio Lopez <slp@redhat.com> Message-Id: <20230714153900.475857-2-ernunes@redhat.com>
2023-07-11Merge tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu ↵Richard Henderson1-3/+25
into staging pc,pci,virtio: cleanups, fixes, features vhost-user-gpu: edid vhost-user-scmi device vhost-vdpa: _F_CTRL_RX and _F_CTRL_RX_EXTRA support for svq cleanups, fixes all over the place. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> # -----BEGIN PGP SIGNATURE----- # # iQFDBAABCAAtFiEEXQn9CHHI+FuUyooNKB8NuNKNVGkFAmSsjYMPHG1zdEByZWRo # YXQuY29tAAoJECgfDbjSjVRp2vYH/20u6TAMssE/UAJoUU0ypbJkbHjDqiqDeuZN # qDYazLUWIJTUbDnSfXAiRcdJuukEpEFcoHa9O6vgFE/SNod51IrvsJR9CbZxNmk6 # D+Px9dkMckDE/yb8f6hhcHsi7/1v04I0oSXmJTVYxWSKQhD4Km6x8Larqsh0u4yd # n6laZ+VK5H8sk6QvI5vMz+lYavACQVryiWV/GAigP21B0eQK79I5/N6y0q8/axD5 # cpeTzUF+m33SfLfyd7PPmibCQFYrHDwosynSnr3qnKusPRJt2FzWkzOiZgbtgE2L # UQ/S4sYTBy8dZJMc0wTywbs1bSwzNrkQ+uS0v74z9wCUYTgvQTA= # =RsOh # -----END PGP SIGNATURE----- # gpg: Signature made Tue 11 Jul 2023 12:00:19 AM BST # gpg: using RSA key 5D09FD0871C8F85B94CA8A0D281F0DB8D28D5469 # gpg: issuer "mst@redhat.com" # gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>" [undefined] # gpg: aka "Michael S. Tsirkin <mst@redhat.com>" [undefined] # gpg: WARNING: This key is not certified with a trusted signature! # gpg: There is no indication that the signature belongs to the owner. # Primary key fingerprint: 0270 606B 6F3C DF3D 0B17 0970 C350 3912 AFBE 8E67 # Subkey fingerprint: 5D09 FD08 71C8 F85B 94CA 8A0D 281F 0DB8 D28D 5469 * tag 'for_upstream' of https://git.kernel.org/pub/scm/virt/kvm/mst/qemu: (66 commits) vdpa: Allow VIRTIO_NET_F_CTRL_RX_EXTRA in SVQ vdpa: Restore packet receive filtering state relative with _F_CTRL_RX_EXTRA feature vdpa: Allow VIRTIO_NET_F_CTRL_RX in SVQ vdpa: Avoid forwarding large CVQ command failures vdpa: Accessing CVQ header through its structure vhost: Fix false positive out-of-bounds vdpa: Restore packet receive filtering state relative with _F_CTRL_RX feature vdpa: Restore MAC address filtering state vdpa: Use iovec for vhost_vdpa_net_load_cmd() pcie: Specify 0 for ARI next function numbers pcie: Use common ARI next function number include/hw/virtio: document some more usage of notifiers include/hw/virtio: add kerneldoc for virtio_init include/hw/virtio: document virtio_notify_config hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments include/hw: document the device_class_set_parent_* fns include: attempt to document device_class_set_props vdpa: Fix possible use-after-free for VirtQueueElement pcie: Add hotplug detect state register to cmask virtio-iommu: Rework the traces in virtio_iommu_set_page_size_mask() ... Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-07-10docs: vhost-user-gpu: add protocol changes for EDIDErico Nunes1-3/+25
VHOST_USER_GPU_GET_EDID is defined as a message from the backend to the frontend to retrieve the EDID data for a given scanout. The VHOST_USER_GPU_PROTOCOL_F_EDID protocol feature is defined as a way to check whether this new message is supported or not. Signed-off-by: Erico Nunes <ernunes@redhat.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20230626164708.1163239-3-ernunes@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-07-10qga: Add new option --allow-rpcsKonstantin Kostiuk1-0/+5
The allow-rpcs option accepts a comma-separated list of RPCs to enable. This option is opposite to --block-rpcs. Using --block-rpcs and --allow-rpcs at the same time is not allowed. resolves: https://gitlab.com/qemu-project/qemu/-/issues/1505 Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>
2023-06-02qcow2: Explicit mention of padding bytesEric Blake1-0/+1
Although we already covered the need for padding bytes with our changes in commit 3ae3fcfa, commit 66fcbca5 (both v5.0.0) added one byte and relied on the rest of the text for implicitly covering 7 padding bytes. For consistency with other parts of the header (such as the header extension format listing padding from n - m, or the snapshot table entry listing variable padding), we might as well call out the remaining 7 bytes as padding until such time (as any) as they gain another meaning. Signed-off-by: Eric Blake <eblake@redhat.com> CC: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Message-Id: <20230522184631.47211-1-eblake@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
2023-05-22Merge tag 'pull-qapi-2023-05-17-v2' of https://repo.or.cz/qemu/armbru into ↵Richard Henderson3-238/+184
staging QAPI patches patches for 2023-05-17 # -----BEGIN PGP SIGNATURE----- # # iQJGBAABCAAwFiEENUvIs9frKmtoZ05fOHC0AOuRhlMFAmRrTcgSHGFybWJydUBy # ZWRoYXQuY29tAAoJEDhwtADrkYZTMycP/3sP6/U4kwOKMGGcB+n2pHJeioQS4xgF # 94NCW+KpewxApP0XzIC2nDGjUe/rPcUfQmBNUumvYbqHO91tq91wFwkllBv2UR0q # 6qfRji+e8+9H9hMDeVzzSNjlZZg/tSdIJlhkJDw1u4/3fpjfAmzVx6DO3wepSQ9Q # m5Af/+uhVZWyUXMZqcKr2Zq8qur6ZFEBNpXpPvT60Tvy2heuQ+vcoE3tl2ZRQbmj # b/jhtCu+NPjgOHtg9Gr2BPXqQiZBR4vFA7WBsB8wCf2xxULfTwHJvFz/e0vx5fUC # q0Fsyybf4USo2PRMsRFv2v4dEuVGHb3E1RIJY4NTAxQMqqm4zfOyK0BzOGNDkxCn # owNP4vKly0e/CfYDY74FHaPId295xyeo6S4Cj5ib9W23AAWUNt6f6vbjlDOLCLON # c7yXP/aJwhTb2w1t0mLTmsKum3DpLlrudPudTylVlmYfwchkvUGsWYbaxu6H6XWk # 49Ox/QPVwqG6elXNn3kTY4QqTAppXhE7QcPbioX9WOThVPf6aJCLdZSHEHu4HXkZ # 4FRu73Z2wcPNB789xOrQoXs24GdKmWXQ6K01KC4v7WNJQBXccec52yGxvktQRZBm # GL3zYdOOJEL+Y/8JrXTIo26M8HP/4kxV2VqB6KOuaGygMsW9w9jbG+ygLyjqUDQg # 3APV3hdmVOht # =6anf # -----END PGP SIGNATURE----- # gpg: Signature made Mon 22 May 2023 04:11:04 AM PDT # gpg: using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653 # gpg: issuer "armbru@redhat.com" # gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [undefined] # gpg: aka "Markus Armbruster <armbru@pond.sub.org>" [undefined] # gpg: WARNING: This key is not certified with a trusted signature! # gpg: There is no indication that the signature belongs to the owner. # Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653 * tag 'pull-qapi-2023-05-17-v2' of https://repo.or.cz/qemu/armbru: docs/interop: Delete qmp-intro.txt docs/interop/qmp-spec: Update error description for parsing errors docs/interop: Convert qmp-spec.txt to rST qapi: Improve error message for description following section Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-05-22docs/interop: Delete qmp-intro.txtPeter Maydell1-88/+0
qmp-intro.txt is quite small and provides very little information that isn't already in the documentation elsewhere. Fold the example command lines into qemu-options.hx, and delete the now-unneeded plain text document. While we're touching the qemu-options.hx documentation text, wordsmith it a little bit and improve the rST formatting. Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20230515162245.3964307-4-peter.maydell@linaro.org> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-05-22docs/interop/qmp-spec: Update error description for parsing errorsPeter Maydell1-1/+1
The description text for a parsing error has changed since the spec doc was first written; update the example in the docs. Suggested-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20230515162245.3964307-3-peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-05-22docs/interop: Convert qmp-spec.txt to rSTPeter Maydell2-150/+184
Convert the qmp-spec.txt document to restructuredText. Notable points about the conversion: * numbers at the start of section headings are removed, to match the style of the rest of the manual * cross-references to other sections or documents are hyperlinked * various formatting tweaks (notably the examples, which need the -> and <- prefixed so the QMP code-block lexer will accept them) * English prose fixed in a few places Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20230515162245.3964307-2-peter.maydell@linaro.org> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> [.. code-block:: dumbed down to :: to work around CI failure]
2023-05-19docs/interop/qcow2.txt: fix description about "zlib" clustersAkihiro Suda1-3/+7
"zlib" clusters are actually raw deflate (RFC1951) clusters without zlib headers. Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp> Message-Id: <168424874322.11954.1340942046351859521-0@git.sr.ht> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-04-28qapi: @foo should be used to reference, not ``foo``Markus Armbruster1-3/+3
Documentation suggests @foo is merely shorthand for ``foo``. It's not, it carries additional meaning: it's a reference to a QAPI schema name. Reword the documentation to spell that out. Fix up the few ``foo`` that should be @foo. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20230425064223.820979-7-armbru@redhat.com>
2023-04-21docs: vhost-user: Add Xen specific memory mapping supportViresh Kumar1-0/+21
The current model of memory mapping at the back-end works fine where a standard call to mmap() (for the respective file descriptor) is enough before the front-end can start accessing the guest memory. There are other complex cases though where the back-end needs more information and simple mmap() isn't enough. For example Xen, a type-1 hypervisor, currently supports memory mapping via two different methods, foreign-mapping (via /dev/privcmd) and grant-dev (via /dev/gntdev). In both these cases, the back-end needs to call mmap() and ioctl(), with extra information like the Xen domain-id of the guest whose memory we are trying to map. Add a new protocol feature, 'VHOST_USER_PROTOCOL_F_XEN_MMAP', which lets the back-end know about the additional memory mapping requirements. When this feature is negotiated, the front-end will send the additional information within the memory regions themselves. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Message-Id: <6d0bd7f0e1aeec3ddb603ae4ff334c75c7d0d7b3.1678351495.git.viresh.kumar@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
2023-04-21docs: vhost-user: Define memory region separatelyViresh Kumar1-21/+18
The same layout is defined twice, once in "single memory region description" and then in "memory regions description". Separate out details of memory region from these two and reuse the same definition later on. While at it, also rename "memory regions description" to "multiple memory regions description", to avoid potential confusion around similar names. And define single region before multiple ones. This is just a documentation optimization, the protocol remains the same. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Message-Id: <7c3718e5eb99178b22696682ae73aca6df1899c7.1678351495.git.viresh.kumar@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
2023-03-02docs: vhost-user: replace _SLAVE_ with _BACKEND_Maxime Coquelin1-20/+20
Backend's message and protocol features names were still using "_SLAVE_" naming. For consistency with the new naming convention, replace it with _BACKEND_. Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com> Message-Id: <20230208203259.381326-2-maxime.coquelin@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-02-02docs: add an introduction to the system docsAlex Bennée2-0/+4
Drop the frankly misleading quickstart section for a more rounded introduction section. This new section gives an overview of the accelerators as well as a high level introduction to some of the key features of the emulator. We also expand on a general form for a QEMU command line with a hopefully not too scary worked example of what this looks like. Acked-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> Message-Id: <20230124180127.1881110-23-alex.bennee@linaro.org>
2023-01-09docs/interop: Change the vnc-ledstate-Pseudo-encoding doc into .rstThomas Huth2-0/+1
The file seems to contain perfectly valid rst syntax already, so rename it to .rst and wire it up in the index. Message-Id: <20221213101806.46640-1-thuth@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2022-10-12docs: add firmware feature flagsGerd Hoffmann1-5/+16
Add new firmware feature flags for the recently added confidential computing operating modes by amd and intel. While being at it also fix the path to the amd sev documentation. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> Message-Id: <20220930133220.1771336-1-kraxel@redhat.com>
2022-09-20qga: Replace 'blacklist' command line and config file options by 'block-rpcs'Thomas Huth1-4/+4
Let's use a more appropriate wording for this command line and config file option. The old ones are still accepted for compatibility reasons, but marked as deprecated now so that it could be removed in a future version of QEMU. This change is based on earlier patches from Philippe Mathieu-Daudé, with the idea for the new option name suggested by BALATON Zoltan. And while we're at it, replace the "?" in the help text with "help" since that does not have the problem of conflicting with the wildcard character of the shells. Message-Id: <20220727092135.302915-2-thuth@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com> Signed-off-by: Thomas Huth <thuth@redhat.com>
2022-08-01misc: fix commonly doubled up wordsDaniel P. Berrangé1-2/+2
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> Message-Id: <20220707163720.1421716-5-berrange@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Thomas Huth <thuth@redhat.com>
2022-06-27docs/vhost-user: Fix mismergeKevin Wolf1-16/+0
This reverts commit 76b1b64370007234279ea4cc8b09c98cbd2523de. The commit only duplicated some text that had already been merged in commit 31009d13cc5. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20220627134500.94842-2-kwolf@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
2022-06-08Fix 'writeable' typosPeter Maydell1-1/+1
We have about 30 instances of the typo/variant spelling 'writeable', and over 500 of the more common 'writable'. Standardize on the latter. Change produced with: sed -i -e 's/\([Ww][Rr][Ii][Tt]\)[Ee]\([Aa][Bb][Ll][Ee]\)/\1\2/g' $(git grep -il writeable) and then hand-undoing the instance in linux-headers/linux/kvm.h. Most of these changes are in comments or documentation; the exceptions are: * a local variable in accel/hvf/hvf-accel-ops.c * a local variable in accel/kvm/kvm-all.c * the PMCR_WRITABLE_MASK macro in target/arm/internals.h * the EPT_VIOLATION_GPA_WRITABLE macro in target/i386/hvf/vmcs.h (which is never used anywhere) * the AR_TYPE_WRITABLE_MASK macro in target/i386/hvf/vmx.h (which is never used anywhere) Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Reviewed-by: Stefan Weil <sw@weilnetz.de> Message-id: 20220505095015.2714666-1-peter.maydell@linaro.org
2022-05-16docs/vhost-user: Clarifications for VHOST_USER_ADD/REM_MEM_REGKevin Wolf1-0/+16
The specification for VHOST_USER_ADD/REM_MEM_REG messages is unclear in several points, which has led to clients having incompatible implementations. This changes the specification to be more explicit about them: * VHOST_USER_ADD_MEM_REG is not specified as receiving a file descriptor, though it obviously does need to do so. All implementations agree on this one, fix the specification. * VHOST_USER_REM_MEM_REG is not specified as receiving a file descriptor either, and it also has no reason to do so. rust-vmm does not send file descriptors for removing a memory region (in agreement with the specification), libvhost-user and QEMU do (which is a bug), though libvhost-user doesn't actually make any use of it. Change the specification so that for compatibility QEMU's behaviour becomes legal, even if discouraged, but rust-vmm's behaviour becomes the explicitly recommended mode of operation. * VHOST_USER_ADD_MEM_REG doesn't have a documented return value, which is the desired behaviour in the non-postcopy case. It also implemented like this in QEMU and rust-vmm, though libvhost-user is buggy and sometimes sends an unexpected reply. This will be fixed in a separate patch. However, in postcopy mode it does reply like VHOST_USER_SET_MEM_TABLE. This behaviour is shared between libvhost-user and QEMU; rust-vmm doesn't implement postcopy mode yet. Mention it explicitly in the spec. * The specification doesn't mention how VHOST_USER_REM_MEM_REG identifies the memory region to be removed. Change it to describe the existing behaviour of libvhost-user (guest address, user address and size must match). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20220407133657.155281-2-kwolf@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2022-05-16vhost-user: more master/slave thingsMichael S. Tsirkin1-1/+1
we switched to front-end/back-end, but newer patches reintroduced old language. Fix this up. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-16vhost-user.rst: add clarifying language about protocol negotiationAlex Bennée1-2/+16
Make the language about feature negotiation explicitly clear about the handling of the VHOST_USER_F_PROTOCOL_FEATURES feature bit. Try and avoid the sort of bug introduced in vhost.rs REPLY_ACK processing: https://github.com/rust-vmm/vhost/pull/24 Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Cc: Jiang Liu <gerry@linux.alibaba.com> Message-Id: <20210226111619.21178-1-alex.bennee@linaro.org> Message-Id: <20220321153037.3622127-8-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-16docs: vhost-user: replace master/slave with front-end/back-endPaolo Bonzini2-180/+180
This matches the nomenclature that is generally used. Also commonly used is client/server, but it is not as clear because sometimes the front-end exposes a passive (server) socket that the back-end connects to. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210226143413.188046-4-pbonzini@redhat.com> Message-Id: <20220321153037.3622127-7-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-16docs: vhost-user: rewrite section on ring state machinePaolo Bonzini1-25/+21
This section is using the word "back-end" to refer to the "slave's back-end", and talking about the "client" for what the rest of the document calls the "slave". Rework it to free the use of the term "back-end", which in the next patch will replace "slave". Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210226143413.188046-3-pbonzini@redhat.com> Message-Id: <20220321153037.3622127-6-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-16docs: vhost-user: clean up request/reply descriptionPaolo Bonzini1-68/+95
It is not necessary to mention which side is sending/receiving each payload; it is more interesting to say which is the request and which is the reply. This also matches what vhost-user-gpu.rst already does. While at it, ensure that all messages list both the request and the reply payload. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20210226143413.188046-2-pbonzini@redhat.com> Message-Id: <20220321153037.3622127-5-alex.bennee@linaro.org> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
2022-05-12nbd/server: Allow MULTI_CONN for shared writable exportsEric Blake1-0/+1
According to the NBD spec, a server that advertises NBD_FLAG_CAN_MULTI_CONN promises that multiple client connections will not see any cache inconsistencies: when properly separated by a single flush, actions performed by one client will be visible to another client, regardless of which client did the flush. We always satisfy these conditions in qemu - even when we support multiple clients, ALL clients go through a single point of reference into the block layer, with no local caching. The effect of one client is instantly visible to the next client. Even if our backend were a network device, we argue that any multi-path caching effects that would cause inconsistencies in back-to-back actions not seeing the effect of previous actions would be a bug in that backend, and not the fault of caching in qemu. As such, it is safe to unconditionally advertise CAN_MULTI_CONN for any qemu NBD server situation that supports parallel clients. Note, however, that we don't want to advertise CAN_MULTI_CONN when we know that a second client cannot connect (for historical reasons, qemu-nbd defaults to a single connection while nbd-server-add and QMP commands default to unlimited connections; but we already have existing means to let either style of NBD server creation alter those defaults). This is visible by no longer advertising MULTI_CONN for 'qemu-nbd -r' without -e, as in the iotest nbd-qemu-allocation. The harder part of this patch is setting up an iotest to demonstrate behavior of multiple NBD clients to a single server. It might be possible with parallel qemu-io processes, but I found it easier to do in python with the help of libnbd, and help from Nir and Vladimir in writing the test. Signed-off-by: Eric Blake <eblake@redhat.com> Suggested-by: Nir Soffer <nsoffer@redhat.com> Suggested-by: Vladimir Sementsov-Ogievskiy <v.sementsov-og@mail.ru> Message-Id: <20220512004924.417153-3-eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-05-04docs/vhost-user: Clarifications for VHOST_USER_ADD/REM_MEM_REGKevin Wolf1-0/+17
The specification for VHOST_USER_ADD/REM_MEM_REG messages is unclear in several points, which has led to clients having incompatible implementations. This changes the specification to be more explicit about them: * VHOST_USER_ADD_MEM_REG is not specified as receiving a file descriptor, though it obviously does need to do so. All implementations agree on this one, fix the specification. * VHOST_USER_REM_MEM_REG is not specified as receiving a file descriptor either, and it also has no reason to do so. rust-vmm does not send file descriptors for removing a memory region (in agreement with the specification), libvhost-user and QEMU do (which is a bug), though libvhost-user doesn't actually make any use of it. Change the specification so that for compatibility QEMU's behaviour becomes legal, even if discouraged, but rust-vmm's behaviour becomes the explicitly recommended mode of operation. * VHOST_USER_ADD_MEM_REG doesn't have a documented return value, which is the desired behaviour in the non-postcopy case. It also implemented like this in QEMU and rust-vmm, though libvhost-user is buggy and sometimes sends an unexpected reply. This will be fixed in a separate patch. However, in postcopy mode it does reply like VHOST_USER_SET_MEM_TABLE. This behaviour is shared between libvhost-user and QEMU; rust-vmm doesn't implement postcopy mode yet. Mention it explicitly in the spec. * The specification doesn't mention how VHOST_USER_REM_MEM_REG identifies the memory region to be removed. Change it to describe the existing behaviour of libvhost-user (guest address, user address and size must match). Signed-off-by: Kevin Wolf <kwolf@redhat.com> Message-Id: <20220407133657.155281-2-kwolf@redhat.com> Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2022-03-06docs: vhost-user: add subsection for non-Linux platformsSergio Lopez1-0/+20
Add a section explaining how vhost-user is supported on platforms other than Linux. Signed-off-by: Sergio Lopez <slp@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20220304100854.14829-5-slp@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-02-16docs: expand firmware descriptor to allow flash without NVRAMDaniel P. Berrangé1-8/+46
The current firmware descriptor schema for flash requires that both the executable to NVRAM template paths be provided. This is fine for the most common usage of EDK2 builds in virtualization where the separate _CODE and _VARS files are provided. With confidential computing technology like AMD SEV, persistent storage of variables may be completely disabled because the firmware requires a known clean state on every cold boot. There is no way to express this in the firmware descriptor today. Even with regular EDK2 builds it is possible to create a firmware that has both executable code and variable persistence in a single file. This hasn't been commonly used, since it would mean every guest bootup would need to clone the full firmware file, leading to redundant duplicate storage of the code portion. In some scenarios this may not matter and might even be beneficial. For example if a public cloud allows users to bring their own firmware, such that the user can pre-enroll their own secure boot keys, you're going to have this copied on disk for each tenant already. At this point the it can be simpler to just deal with a single file rather than split builds. The firmware descriptor ought to be able to express this combined firmware model too. This all points towards expanding the schema for flash with a 'mode' concept: - "split" - the current implicit behaviour with separate files for code and variables. - "combined" - the alternate behaviour where a single file contains both code and variables. - "stateless" - the confidential computing use case where storage of variables is completely disable, leaving only the code. Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2022-01-07docs: reSTify virtio-balloon-stats documentation and move to docs/interopThomas Huth2-0/+112
The virtio-balloon-stats documentation might be useful for people that are implementing software that talks to QEMU via QMP, so this should reside in the docs/interop/ directory. While we're at it, also convert the file to restructured text and mention it in the MAINTAINERS file. Signed-off-by: Thomas Huth <thuth@redhat.com> Message-Id: <20220105115245.420945-1-thuth@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2021-12-21docs: add dbus-display documentationMarc-André Lureau3-0/+34
Wire up the dbus-display documentation. The interface and feature is implemented next. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
2021-12-21docs: move D-Bus VMState documentation to source XMLMarc-André Lureau1-44/+8
Use the source XML document as single reference, importing its documentation via the dbus-doc directive. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Acked-by: Gerd Hoffmann <kraxel@redhat.com>
2021-11-19docs: Spell QEMU all capsPhilippe Mathieu-Daudé2-7/+7
Replace Qemu -> QEMU. Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Darren Kenny <darren.kenny@oracle.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20211118143401.4101497-1-philmd@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-11-09qapi: deprecate drive-backupVladimir Sementsov-Ogievskiy1-16/+31
Modern way is using blockdev-add + blockdev-backup, which provides a lot more control on how target is opened. As example of drive-backup problems consider the following: User of drive-backup expects that target will be opened in the same cache and aio mode as source. Corresponding logic is in drive_backup_prepare(), where we take bs->open_flags of source. It works rather bad if source was added by blockdev-add. Assume source is qcow2 image. On blockdev-add we should specify aio and cache options for file child of qcow2 node. What happens next: drive_backup_prepare() looks at bs->open_flags of qcow2 source node. But there no BDRV_O_NOCAHE neither BDRV_O_NATIVE_AIO: BDRV_O_NOCAHE is places in bs->file->bs->open_flags, and BDRV_O_NATIVE_AIO is nowhere, as file-posix parse options and simply set s->use_linux_aio. The documentation is updated in a minimal way, so that drive-backup is noted only as a deprecated command, and blockdev-backup used in most of places. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
2021-11-09docs/interop/bitmaps: use blockdev-backupVladimir Sementsov-Ogievskiy1-70/+215
We are going to deprecate drive-backup, so use modern interface here. In examples where target image creation is shown, show blockdev-add as well. If target creation omitted, omit blockdev-add as well. Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-11-08docs: remove non-reference uses of single backticksJohn Snow1-1/+1
The single backtick markup in ReST is the "default role". Currently, Sphinx's default role is called "content". Sphinx suggests you can use the "Any" role instead to turn any single-backtick enclosed item into a cross-reference. This is useful for things like autodoc for Python docstrings, where it's often nicer to reference other types with `foo` instead of the more laborious :py:meth:`foo`. It's also useful in multi-domain cases to easily reference definitions from other Sphinx domains, such as referencing C code definitions from outside of kerneldoc comments. Before we do that, though, we'll need to turn all existing usages of the "content" role to inline verbatim markup wherever it does not correctly resolve into a cross-refernece by using double backticks instead. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Reviewed-by: Alexander Bulekov <alxndr@bu.edu> Message-Id: <20211004215238.1523082-2-jsnow@redhat.com>
2021-09-13docs: standardize directory index to --- with overlinePaolo Bonzini1-1/+2
Use a standard heading format for the index.rst file in a directory. Using overlines makes it clear that individual documents can use e.g. === for chapter titles and --- for section titles, as suggested in the Linux kernel guidelines[1]. They could do it anyway, because documents included in a toctree are parsed separately and therefore are not tied to the same conventions for headings. However, keeping some consistency is useful since sometimes files are included from multiple places. [1] https://www.kernel.org/doc/html/latest/doc-guide/sphinx.html Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-08-02docs: Move the protocol part of barrier.txt into interopPeter Maydell2-0/+427
Most of docs/barrier.txt is describing the protocol implemented by the input-barrier device. Move this into the interop section of the manual, and rstify it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Laurent Vivier <laurent@vivier.eu> Message-id: 20210727204112.12579-2-peter.maydell@linaro.org
2021-08-02docs: Format literals correctlyPeter Maydell1-1/+1
In rST markup, single backticks `like this` represent "interpreted text", which can be handled as a bunch of different things if tagged with a specific "role": https://docutils.sourceforge.io/docs/ref/rst/restructuredtext.html#interpreted-text (the most common one for us is "reference to a URL, which gets hyperlinked"). The default "role" if none is specified is "title_reference", intended for references to book or article titles, and it renders into the HTML as <cite>...</cite> (usually comes out as italics). This commit fixes various places in the manual which were using single backticks when double backticks (for literal text) were intended, and covers those files where only one or two instances of these errors were made. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2021-08-02docs: Move licence/copyright from HTML output to rST commentsPeter Maydell2-8/+11
Our built HTML documentation now has a standard footer which gives the license for QEMU (and its documentation as a whole). In almost all pages, we either don't bother to state the copyright/license for the individual rST sources, or we put it in an rST comment. There are just three pages which render copyright or license information into the user-visible HTML. Quoting a specific (different) license for an individual HTML page within the manual is confusing. Downgrade the license and copyright info to a comment within the rST source, bringing these pages in line with the rest of our documents. Suggested-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Cleber Rosa <crosa@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Message-id: 20210722192016.24915-3-peter.maydell@linaro.org