From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202510 header.b=dFyLrtsj; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 172CE5A0BB9 for ; Mon, 10 Nov 2025 07:16:20 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202510; t=1762755377; bh=FCiXMEcA37pX4fehwyOvUhgHU2PtYTdfato27Gd/xGA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dFyLrtsjVw3vl5NmKQxOt55QFErFVTZmB1Om1E6lr1ouglpoDKLxHRxTFfZJnuJVj oyhbhERtZEjtN42TNv9rQ4iy0yjSkdwaVL3H6+sgLPH6MTFOpbP/sVLSgWQ/tdy4aF d7oZBpEXgHEIYn4Bs1OnWAd7O7njpUgkW9CmtIFunoOGhWuPPyWFlaR+6VvwyhyI7V fxI93udincn0Xz53ql18JKCutic6DxZVYAYg7nCGJYVBxuxNLxiioew7wHlw8GAV45 Yn2W8sTFU2nXQ7Hz/VUQc4jIQQ41i07A9flEm8MVY++LGZGptnkbvFkt9UuHax1DgH 06GznAYQyzmzg== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4d4fYs2LsHz4w93; Mon, 10 Nov 2025 17:16:17 +1100 (AEDT) Date: Mon, 10 Nov 2025 17:16:13 +1100 From: David Gibson To: Stefano Brivio Subject: Re: Port Forwarding between host-guest via passt using QEMU-libvirt Message-ID: References: <20251106133736.40e4117e@elisabeth> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Wt/efLzoYWlulgN9" Content-Disposition: inline In-Reply-To: <20251106133736.40e4117e@elisabeth> Message-ID-Hash: KROI5T7YCRPX6MC5VYO53FUMLYB36QZ3 X-Message-ID-Hash: KROI5T7YCRPX6MC5VYO53FUMLYB36QZ3 X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: James Sinton , passt-user@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: "For passt users: support, questions and answers" Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --Wt/efLzoYWlulgN9 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Nov 06, 2025 at 01:37:36PM +0100, Stefano Brivio wrote: > On Thu, 6 Nov 2025 12:08:07 +1100 > David Gibson wrote: >=20 > > That information might supply some clues, but it's pretty likely we'll > > need debugging or packet capture output from passt to work this out. > > Unfortunately, that's a bit trickier than it should be because libvirt > > doesn't (yet) have the ability to pass the necessary options to passt. >=20 > By the way, this feature request for libvirt is currently tracked at > (public RHEL ticket, but applies to libvirt in general): >=20 > https://issues.redhat.com/browse/RHEL-52281 >=20 > Meanwhile, one thing you can do is to add a wrapper at > /usr/local/bin/passt (don't forget to chmod 755 it) with these lines: >=20 > --- > #!/bin/sh >=20 > /usr/bin/passt --debug --log-file /tmp/passt.log --pcap /tmp/passt.pcap $@ > --- >=20 > that's the way I currently debug stuff with libvirt, at least. >=20 > Note that passt can take guest-side packet captures (you would find it > at /tmp/passt.pcap, which you can open with Wireshark / tshark later), > which is usually convenient for cases like these. Right. I think this is the way forward, awkward though it is. I was considering an alternative approach: to kill the passt instance started by libvirt and manually restart it with the options we want. That requires a pretty recent qemu to reliably reconnect to the new passt, though, and generally has more places something could go wrong. The wrapper script is the way to go, thanks for the instructions Stefano. --=20 David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson --Wt/efLzoYWlulgN9 Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmkRgywACgkQzQJF27ox 2GfljA/9HLeS63RCsrmDl45es7Ku2hFzdGxw93qb2Df0GbEnYB4N0UG+V5FqCMLt UBGQnRY2xzSIooTbjJKNMCVpKbA2KeEzyet+iFkzstmXYjdeeJJVkkgmQkY21+RY fTtxvUzjg+z8WvFdX75Md51m9wjhBvAdLFTAAyRWjrzMRp+e+IfzoSvRFzL1j3Q8 6NhArCSAQ+JwjCQjOWnt2tkJ+TsKsCmgonAxZNB8SBUHbltp20bTjjx7pkZGpta+ iKZ8u1oYp2SdcJ7w8BRAJx/79FV3yrN64crlCC0LJOKSwI+5ivu1q9LcVX7avw3u R728gt/PanI098saK65M+YeEydIidokk2KiGdNztyy5CdhvfztLaylcqxv4Ruceo +jeKxxJnL2JKCSQ2h7TjhD4bqvI3PuM10Boq6IUat4/4VgJYwtbQGv3DPU6H3tnx qTJlxVeAegNEIVAOlM1Jy5gc5VLmJL56tz0otFRy20IRw/SWrmANtFw44fq8/kNX fcU0FX5cWD8QtTGBb+0Z/nlzuPhF/5cEYRxnzhCaa6BQXyCbMPDvykiO4ag3CaJG 5sClRbCYMhUACz2upUUov/4m+Yr1gE9ZZYcUdDWNyoTzQPp4Zm+2lL4UXhJY22JP IOlC13NU7Qyxh0z3rgw3fHZtmkVPvtZsgHoSJqcLvZ7vELrpnwY= =mfw5 -----END PGP SIGNATURE----- --Wt/efLzoYWlulgN9--