Add support for mounting a shared folder between the host and guest via virtiofs (v2) #93
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nathanchance
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msfjarvis,
nickdesaulniers and
tpimh
as code owners
This will come in handy in trying to warn people when they are missing configurations needed for certain features. Signed-off-by: Nathan Chancellor <nathan@kernel.org>
…rtiofs virtiofs, available in QEMU 5.2 or newer and Linux guests 5.4 or newer, is a more modern way to pass local folders along to QEMU, as it takes advantage of the fact that the folders are on the same machine as the hypervisor. To use virtiofs, we first need to find and run virtiofsd, which has two different implementations: a C implementation included with QEMU up until 8.0 (available on most distros) and a standalone Rust implementation available on GitLab (not packaged on many distros but easy to build and install). Once we find it, we run it in the background and connect to it using some QEMU parameters, which were shamelessly taken from the official virtiofs website: https://virtio-fs.gitlab.io/howto-qemu.html To use it within the guest (you can use a different path than /mnt/shared but 'mount -t virtio shared' must be used): # mkdir /mnt/shared # mount -t virtiofs shared /mnt/shared # echo "$(uname -a)" >/mnt/shared/foo On the host: $ cat shared/foo Linux (none) 6.1.0-rc8-next-20221207 ClangBuiltLinux#2 SMP PREEMPT Wed Dec 7 14:56:03 MST 2022 aarch64 GNU/Linux This does require guest kernel support (CONFIG_VIRTIO_FS=y), otherwise it will not work inside the guest: / # mount -t virtiofs shared /mnt/shared mount: mounting shared on /mnt/shared failed: No such device Closes: ClangBuiltLinux#81 Link: https://gitlab.com/virtio-fs/virtiofsd Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
…mentations of virtiofsd
In at least virtiofsd 1.6.1 (the Rust implementation), the '-o' options
warn that they are deprecated and the '--help' text agrees:
[2023-07-19T19:32:50Z WARN virtiofsd] Use of deprecated option format '-o': Please specify options without it (e.g., '--cache auto' instead of '-o cache=auto')
-o <compat-options>...
Options in a format compatible with the legacy implementation [deprecated]
To defend against a release removing the deprecated option and breaking
the invocation, maintain two sets of arguments depending on what
implementation is being used. This allows us to drop support for the C
implementation once the Rust one is more widely available in
distributions.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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virtiofs, available in QEMU 5.2 or newer and Linux guests 5.4 or newer,
is a more modern way to pass local folders along to QEMU, as it takes
advantage of the fact that the folders are on the same machine as the
hypervisor.
To use virtiofs, we first need to find and run
virtiofsd, which has twodifferent implementations: a C implementation included with QEMU up until
8.0 (available on most distros) and a standalone Rust implementation
available on GitLab (not packaged on many distros but easy to build and
install). Once we find it, we run it in the background and connect to it
using some QEMU parameters, which were shamelessly taken from the
official virtiofs website:
https://virtio-fs.gitlab.io/howto-qemu.html
To use it within the guest (you can use a different path than
/mnt/sharedbutmount -t virtio sharedmust be used):On the host:
This does require guest kernel support (
CONFIG_VIRTIO_FS=y), otherwise it willnot work inside the guest; the script warns when there is a possibility this
configuration is not set so the user is not surprised by the following error:
Closes: #81
Link: https://gitlab.com/virtio-fs/virtiofsd