Re: [libvirt PATCHv2 09/10] qemu: build vhost-user-fs device command line
On Thu, Jan 23, 2020 at 18:46:10 +0100, Ján Tomko wrote:
Format the 'vhost-user-fs' device on the QEMU command line.
https://bugzilla.redhat.com/show_bug.cgi?id=1694166
Rather than posting this bugzilla link to a not very descriptive bug it
would be worthwhile to describe what the device actually does and how it
integrates with the daemon.
Signed-off-by: Ján Tomko <jtomko(a)redhat.com>
---
src/qemu/qemu_command.c | 47 ++++++++++++++++++-
...vhost-user-fs-fd-memory.x86_64-latest.args | 38 +++++++++++++++
...vhost-user-fs-hugepages.x86_64-latest.args | 46 ++++++++++++++++++
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 974c2b79af..31573860dd 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -2581,6 +2581,47 @@ qemuBuildDisksCommandLine(virCommandPtr cmd,
}
+static int
+qemuBuildVHostUserFsCommandLine(virCommandPtr cmd,
+ virDomainFSDef *fs,
+ const virDomainDef *def G_GNUC_UNUSED,
+ qemuDomainObjPrivatePtr priv)
+{
+ g_autofree char *chardev_alias = NULL;
+ g_auto(virBuffer) opt = VIR_BUFFER_INITIALIZER;
+ const char *tag = fs->dst;
+
+ chardev_alias = g_strdup_printf("chr-vu-%s", fs->info.alias);
I don't like to see another alias generated in the command line
generator and then thrown away. Unfortunately it's still a common
practice.
+
+ virCommandAddArg(cmd, "-chardev");
+ virBufferAddLit(&opt, "socket");
+ virBufferAsprintf(&opt, ",id=%s", chardev_alias);
+ virBufferEscapeString(&opt, ",path=%s",
QEMU_DOMAIN_FS_PRIVATE(fs)->vhostuser_fs_sock);
+ virCommandAddArg(cmd, virBufferContentAndReset(&opt));
+
+ 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);
+ virBufferEscapeString(&opt, ",tag=%s", tag);
fs->dst is user-provided and not validated. It must be escaped on the
command line.
+ if (fs->cache_size)
+ virBufferAsprintf(&opt, ",cache-size=%lluK", fs->cache_size);
Hmm, so only cache size and queue is relevant for the device itself. I
think the options in the XML should reflect that.
I'll mention this in the XML schema patch.
+ 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));
+ return 0;
+}
+
+
static char *
qemuBuildFSStr(virDomainFSDefPtr fs)
{
@@ -2673,7 +2714,7 @@ static int
qemuBuildFilesystemCommandLine(virCommandPtr cmd,
const virDomainDef *def,
virQEMUCapsPtr qemuCaps,
- qemuDomainObjPrivatePtr priv G_GNUC_UNUSED)
+ qemuDomainObjPrivatePtr priv)
{
size_t i;