Re: [PATCH 5/5] qemu: make passt+vhostuser reconnect behave identically to passt+user

On 4/10/25 2:55 AM, Jiri Denemark wrote: > On Thu, Apr 10, 2025 at 02:58:30 -0400, Laine Stump wrote: >> When "original passt" support was added, we decided that we always >> wanted to reconnect (i.e. restart the passt process) if it was somehow >> terminated. Generic vhost-user only turns on reconnect if specified in >> the config, but there is no reason to require this if the other end of >> the vhost-user socket is a passt process - we know what has happened >> and what we want to do; no reason to make the default configuration >> "do the *wrong* thing". >> >> Resolves: https://issues.redhat.com/browse/RHEL-80169 >> >> Signed-off-by: Laine Stump <laine(a)redhat.com&gt; >> --- >> src/qemu/qemu_passt.c | 6 ++++++ >> .../qemuxmlconfdata/net-vhostuser-passt.x86_64-latest.args | 6 +++--- >> .../schema-reorder-domain-subelements.x86_64-latest.args | 2 +- >> 3 files changed, 10 insertions(+), 4 deletions(-) >> >> diff --git a/src/qemu/qemu_passt.c b/src/qemu/qemu_passt.c >> index bc495eca1e..018630a5de 100644 >> --- a/src/qemu/qemu_passt.c >> +++ b/src/qemu/qemu_passt.c >> @@ -182,6 +182,12 @@ qemuPasstPrepareVhostUser(virDomainObj *vm, >> */ >> g_free(net->data.vhostuser->data.nix.path); >> net->data.vhostuser->data.nix.path = qemuPasstCreateSocketPath(vm, net); >> + >> + /* reconnect is always enabled, with timeout always at 5 seconds, when >> + * using passt >> + */ >> + net->data.vhostuser->data.nix.reconnect.enabled = VIR_TRISTATE_BOOL_YES; >> + net->data.vhostuser->data.nix.reconnect.timeout = 5;

> Actually, looking at our > documentation the <reconnect> it seems we don't even support setting > reconnect for vhost-user with passt backend. Correct. This is the same behavior as for non-vhostuser passt, where we decided that there was no downside to having reconnect always enabled and no reasonable way to explain how or why a user should modify the timeout, so made it always on and always 5 second timeout.

> If that's the case, the > code is fine as is except for the following nit, which I'd like to see > addressed anyway... > > And I suggest relacing the 5 seconds timeout with a macro that would > also be used in qemuPasstAddNetProps. Sure, I can do that. Thanks for the quick review!