[libvirt PATCHv4 14/15] qemu: build vhost-user-fs device command line

Peter Krempa pkrempa at redhat.com
Wed Feb 26 09:11:30 UTC 2020


On Thu, Feb 20, 2020 at 15:32:51 +0100, Ján Tomko wrote:
> Format the 'vhost-user-fs' device on the QEMU command line.
> 
> This device provides shared file system access using the FUSE protocol
> carried over virtio.
> The actual file server is implemented in an external vhost-user-fs device
> backend process.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1694166
> 
> Signed-off-by: Ján Tomko <jtomko at redhat.com>
> Reviewed-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  src/qemu/qemu_command.c                       | 45 +++++++++++++++++-
>  ...vhost-user-fs-fd-memory.x86_64-latest.args | 39 +++++++++++++++
>  ...vhost-user-fs-hugepages.x86_64-latest.args | 47 +++++++++++++++++++
>  tests/qemuxml2argvtest.c                      |  3 ++
>  4 files changed, 132 insertions(+), 2 deletions(-)
>  create mode 100644 tests/qemuxml2argvdata/vhost-user-fs-fd-memory.x86_64-latest.args
>  create mode 100644 tests/qemuxml2argvdata/vhost-user-fs-hugepages.x86_64-latest.args
> 
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 9fcd06f8c3..272a0b8d44 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -2574,6 +2574,45 @@ qemuBuildDisksCommandLine(virCommandPtr cmd,
>  }
>  
>  
> +static int
> +qemuBuildVHostUserFsCommandLine(virCommandPtr cmd,
> +                                virDomainFSDef *fs,
> +                                const virDomainDef *def,
> +                                qemuDomainObjPrivatePtr priv)
> +{
> +    g_autofree char *chardev_alias = NULL;
> +    g_auto(virBuffer) opt = VIR_BUFFER_INITIALIZER;
> +
> +    chardev_alias = g_strdup_printf("chr-vu-%s", fs->info.alias);

Neither this function nor any other place actually checks that qemu
supports QEMU_CAPS_DEVICE_VHOST_USER_FS. Actually the capability is only
ever mentioned in qemu_capabilities.(c|h).

> +    virCommandAddArg(cmd, "-chardev");
> +    virBufferAddLit(&opt, "socket");
> +    virBufferAsprintf(&opt, ",id=%s", chardev_alias);
> +    virBufferEscapeString(&opt, ",path=%s", QEMU_DOMAIN_FS_PRIVATE(fs)->vhostuser_fs_sock);

This function is for escaping the string for XML use not shell use.

> +    virCommandAddArg(cmd, virBufferContentAndReset(&opt));

virCommandAddArgBuffer

> +
> +    virCommandAddArg(cmd, "-device");
> +
> +    if (qemuBuildVirtioDevStr(&opt, "vhost-user-fs", priv->qemuCaps,
> +                              VIR_DOMAIN_DEVICE_FS, fs) < 0)
> +        return -1;
> +
> +    virBufferAsprintf(&opt, ",chardev=%s", chardev_alias);
> +    if (fs->queue_size)
> +        virBufferAsprintf(&opt, ",queue-size=%llu", fs->queue_size);
> +    virBufferAddLit(&opt, ",tag=");
> +    virQEMUBuildBufferEscapeComma(&opt, fs->dst);

This one is correct ;)

> +    if (qemuBuildVirtioOptionsStr(&opt, fs->virtio, priv->qemuCaps) < 0)
> +        return -1;
> +
> +    if (qemuBuildDeviceAddressStr(&opt, def, &fs->info, priv->qemuCaps) < 0)
> +        return -1;
> +
> +    virCommandAddArg(cmd, virBufferContentAndReset(&opt));

virCommandAddArgBuffer

> +    return 0;
> +}
> +
> +




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