| 2dcbb11b | 25-Sep-2023 |
Eric Blake <eblake@redhat.com> |
nbd/server: Add FLAG_PAYLOAD support to CMD_BLOCK_STATUS
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
nbd/server: Add FLAG_PAYLOAD support to CMD_BLOCK_STATUS
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>
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| 0ec4468f | 15-May-2023 |
Peter Maydell <peter.maydell@linaro.org> |
docs/interop: Delete qmp-intro.txt
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-opti
docs/interop: Delete qmp-intro.txt
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>
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| 8a85b8ec | 15-May-2023 |
Peter Maydell <peter.maydell@linaro.org> |
docs/interop/qmp-spec: Update error description for parsing errors
The description text for a parsing error has changed since the
spec doc was first written; update the example in the docs.
Suggest
docs/interop/qmp-spec: Update error description for parsing errors
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>
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| f21e95ee | 09-Mar-2023 |
Viresh Kumar <viresh.kumar@linaro.org> |
docs: vhost-user: Add Xen specific memory mapping support
The current model of memory mapping at the back-end works fine where a
standard call to mmap() (for the respective file descriptor) is enoug
docs: vhost-user: Add Xen specific memory mapping support
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>
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