From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48880) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cTERK-0005CR-0O for qemu-devel@nongnu.org; Mon, 16 Jan 2017 16:03:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cTERG-0007tO-Rz for qemu-devel@nongnu.org; Mon, 16 Jan 2017 16:03:42 -0500 Received: from mail-it0-x243.google.com ([2607:f8b0:4001:c0b::243]:33065) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cTERG-0007t5-Md for qemu-devel@nongnu.org; Mon, 16 Jan 2017 16:03:38 -0500 Received: by mail-it0-x243.google.com with SMTP id v14so13564409itb.0 for ; Mon, 16 Jan 2017 13:03:37 -0800 (PST) References: <20170112114612.14520-1-stefanha@redhat.com> <20170113120240.GB9142@stefanha-x1.localdomain> <75cb767b-2850-4a87-50fc-d957e3a793ac@cardoe.com> <20170116104613.GB12351@stefanha-x1.localdomain> From: Doug Goldstein Message-ID: Date: Mon, 16 Jan 2017 16:03:28 -0500 MIME-Version: 1.0 In-Reply-To: <20170116104613.GB12351@stefanha-x1.localdomain> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="0LpjANfcv712XnxoHcdEnBbeXWhApJjRi" Subject: Re: [Qemu-devel] [PATCH 0/2] virtio: revert virtio_queue_set_notification() nesting List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" , "Dr . David Alan Gilbert" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --0LpjANfcv712XnxoHcdEnBbeXWhApJjRi From: Doug Goldstein To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" , "Dr . David Alan Gilbert" Message-ID: Subject: Re: [PATCH 0/2] virtio: revert virtio_queue_set_notification() nesting References: <20170112114612.14520-1-stefanha@redhat.com> <20170113120240.GB9142@stefanha-x1.localdomain> <75cb767b-2850-4a87-50fc-d957e3a793ac@cardoe.com> <20170116104613.GB12351@stefanha-x1.localdomain> In-Reply-To: <20170116104613.GB12351@stefanha-x1.localdomain> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 1/16/17 5:46 AM, Stefan Hajnoczi wrote: > On Fri, Jan 13, 2017 at 09:15:49AM -0600, Doug Goldstein wrote: >> On 1/13/17 6:02 AM, Stefan Hajnoczi wrote: >>> On Thu, Jan 12, 2017 at 10:57:53AM -0600, Doug Goldstein wrote: >>>> On 1/12/17 5:46 AM, Stefan Hajnoczi wrote: >>>>> The virtio_queue_set_notification() nesting introduced for AioConte= xt polling >>>>> raised an assertion with virtio-net (even in non-polling mode). Co= nverting >>>>> virtio-net and virtio-crypto to use virtio_queue_set_notification()= in a >>>>> nesting fashion would be invasive and isn't worth it. >>>>> >>>>> Patch 1 contains the revert to resolve the bug that Doug noticed. >>>>> >>>>> Patch 2 is a less efficient but safe alternative. >>>>> >>>>> Stefan Hajnoczi (2): >>>>> Revert "virtio: turn vq->notification into a nested counter" >>>>> virtio: disable notifications again after poll succeeded >>>>> >>>>> hw/virtio/virtio.c | 21 +++++++++------------ >>>>> 1 file changed, 9 insertions(+), 12 deletions(-) >>>>> >>>> >>>> So I just gave this series a whirl and it fixes the assert but cause= s >>>> another issue for me. While iPXE is getting a DHCP address the scree= n >>>> immediately flashes over to the UEFI shell. Its like a timeout is >>>> getting hit and just dropping me to the shell. >>> >>> Sounds like an separate problem. >>> >>> Stefan >>> >> >> Is there any debug output that I can provide to help troubleshoot it? >> I've built 23425cc and UEFI via OVMF is able to get an IP address via >> DHCP inside of iPXE. I've also taken master and only applied the first= >> patch in this series (the revert) and it too works. Its only when I ad= d >> the 2nd patch into the mix or don't revert out the "virtio: turn >> vq->notification into a nested counter" patch that it fails. >=20 > The code in Patch 2 should not be executed in your QEMU configuration, > so I wonder how Patch 2 can cause the DHCP failure. >=20 > Please verify as follows: >=20 > $ gdb --args path/to/qemu-system-x86_64 ... > (gdb) handle SIGUSR1 noprint nostop pass > (gdb) handle SIGPIPE noprint nostop pass > (gdb) b virtio_queue_host_notifier_aio_poll_begin > (gdb) r >=20 > I predict the breakpoint will not be hit. >=20 > Stefan >=20 Correct. That did not hit. I reapplied both patches to my current master and it did not hit but it still dropped me to the EFI shell while iPXE was negotiating DHCP. I then rebased on top of the latest master (2ccede18bd24fce5db83fef3674563a1f256717b) and applied both patches. The iPXE issue went away and the assert issue went away. So I will concur with you, the issue was not in either of these patches and is now resolved. --=20 Doug Goldstein --0LpjANfcv712XnxoHcdEnBbeXWhApJjRi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0 iQJ8BAEBCgBmBQJYfTUjXxSAAAAAAC4AKGlzc3Vlci1mcHJAbm90YXRpb25zLm9w ZW5wZ3AuZmlmdGhob3JzZW1hbi5uZXRBNTM5MEQ2RTNFMTkyNzlCNzVDMzIwOTVB MkJDMDNEQzg3RUQxQkQ0AAoJEKK8A9yH7RvUvbwP/RHoH7yMC4YXL6T8RljWK0Ks IuttsqnXZJS7/RUrVCpwD3bvml+Qi91xAYhyRxBD9vTePNM+JduRAkSaBGcyi702 oOGP1nhCSYYc41qsc66PZBu/44U9kJBtkd/5LrqFvuDVgqvyyrlTYLCfUAZLqdZW E/alOS6Jf0agtWq9XhIRSY1BbjFfwG5+b3Vo+qlRrk+lRrnZwJQ6OSPq6sZUjT9N qFTt5C/Vi+MMoljzjoiVcJjWl2nc/llj4kwVxs+74q45OC9IVdVcDemjAoZxF9s4 7XbTDFleI62ncYXyY5hC2OqnkYRaiW6D0G4gBgIoIhpAUIx1ugHXyVXQd575M/AW OgftAF5EBJWmzMkFw1ROmj4QY3Iq3n5M2X7cFzgPFafCKISbASUSX6JwLCVfBMWx P79XCq97zgJjpmLRpUcEChTEdRF2rJW5jmHak+RpFO2hgekEoXHu5XdJ6BXcdYYR 9JZK4hKeIgsBgrnPdZGtStNSrQOJ4YQtxL2GzadJwsIt2zG0tcDTx0Uz0gMMNf03 GodZuwRDM+0rz0s0TT1hpOSX/fo3NFtt2Yz1OH3Nby0YLrqx7KB/g6HBcIhbl4rN IBwB8KcSZCsXzx2KoyU4Demn6HDtuAZZBcKU4Ge9mtONU7zU7CIo42My3a6k/+aw K1J2CL1J0rd1juxC/827 =6inU -----END PGP SIGNATURE----- --0LpjANfcv712XnxoHcdEnBbeXWhApJjRi--