[ipxe-devel] virtnet_open_legacy() fails to find virtqueues on Google Compute Engine

Ladi Prosek lprosek at redhat.com
Mon Dec 19 16:21:22 GMT 2016


On Mon, Dec 19, 2016 at 10:40 AM, Akihiro Suda <suda.kyoto at gmail.com> wrote:

> Hello, Ladi,
>
> Thank you a lot for providing the patch.
> However, unfortunately, it does not seem to have any effect.
>
> BTW, when I was tackling with the issue without your patch, I found some
> interesting behavior:
>
> - Pinging from another instance (Linux) to an iPXE instance seems always
> working as expected. (i.e. iPXE can successfully "pong" by transmitting
> Ethernet packets)
> - When an iPXE instance is being pinged, it can successfully send
> non-"pong" packets as well. So `dhcp` and `imgfetch
> http://10.146.0.2/a.ipxe` <http://10.146.0.2/a.ipxe> work!
>
> So, I guess the issue is somehow related to interruption.
> When iPXE is frequently interrupted due to RX, the interruptions seems
> triggering TX as well.
> However, TX seems failing when it is not triggered by frequent RX
> interruptions.
> (Please correct me if my guess is wrong ��)
>
>
iPXE doesn't rely on interrupts, virtqueues are polled in a loop. The log
you posted suggests that the host is really transmitting, or at least
accepting outbound packets for transmission. I'm not sure what guest driver
issue would explain this behavior :(

Could you please help me set up a GCE instance with iPXE? I haven't been
able to make it produce any output. Do you build iPXE with CONSOLE_SERIAL?
How do you create the .tar.gz for GCE to import the image from? Thanks!



>
> 2016-12-19 18:00 GMT+09:00 Ladi Prosek <lprosek at redhat.com>:
>
>> Hi Akihiro,
>>
>> On Mon, Dec 19, 2016 at 7:17 AM, Akihiro Suda <suda.kyoto at gmail.com>
>> wrote:
>> > Hello Ladi,
>> >
>> > Thank you a lot for looking into this issue and writing patches about
>> the
>> > queue size. The patch set looks good to me.
>> >
>> >>> I haven't captured DHCP packets (because I'm unsure how to do so in
>> GCE's
>> >>> fully managed DHCP server), but I guess DHCPACK is actually sent from
>> the
>> >>> DHCP server but somehow iPXE missed it.
>> >>
>> >> Do you see any interesting log output with DEBUG=virtio-net,virtio-pci
>> ?
>> >
>> > Did not see any interesting log. No error about TX is printed, and it
>> just
>> > fails to receive DHCPACK.
>> >
>> > So, for ease of debugging with capturing packets, I tried to do
>> `imgfetch
>> > http://...` with a static IP address (`set net0/ip`) instead.
>> >
>> > The result implies that "iPXE believes it has sent the second Ethernet
>> > packet without an error, but it is not sent actually".
>> >
>> > This assumption is consistent with my report about DHCP.
>> > iPXE can successfully send the 1st packet (DHCPDISCOVER), but seems
>> failing
>> > to send the 2nd packet (DHCPREQUEST). It should be the reason why it
>> cannot
>> > receive DHCPACK.
>> >
>> >
>> > Here is the log. In the client log, we can see "TX ... PSH ACK", but it
>> is
>> > not received on the server side.
>> >
>> > === iPXE Client 10.146.0.10 (DEBUG=virtio-net:7,virtio-pci
>> :7,tcp:7,ipv4:7
>> > CONFIG=cloud, 26050fd4 with Ladi's 4 great patches) ===
>> >
>> >     iPXE> imgfetch http://10.146.0.2/a.ipxe
>> >     http://10.146.0.2/a.ipxe...TCP 0x12eda4 allocated
>> >     TCP 0x12eda4 transitioned from CLOSED to SYN_SENT
>> >     TCP 0x12eda4 bound to port 46673
>> >     TCP 0x12eda4 timer fired in SYN_SENT for 609cb55e..609cb55e 00000000
>> >     TCP 0x12eda4 TX 46673->80 609cb55e..609cb55f           00000000
>> 0 SYN
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 64 proto 6 id 0100 csum 6489
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ef90 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ef90
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x12f5f4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1335f4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x12eda4 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc
>> 0 SYN
>> > ACK
>> >     TCP 0x12eda4 using timestamps, SACK, TX window x128, RX window x512
>> >     TCP 0x12eda4 transitioned from SYN_SENT to ESTABLISHED
>> >     TCP 0x12eda4 TX 46673->80 609cb55f..609cb5c1           5ae4dacc
>>  98 PSH
>> > ACK
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 150 proto 6 id 0201 csum 6332
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ec94 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ec94
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x12fdf4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12f5f4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x12eda4 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc
>> 0 SYN
>> > ACK
>> >     TCP 0x12eda4 timer fired in ESTABLISHED for 609cb55f..609cb5c1
>> 5ae4dacc
>> >     TCP 0x12eda4 TX 46673->80 609cb55f..609cb5c1           5ae4dacc
>>  98 PSH
>> > ACK
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 150 proto 6 id 0302 csum 6231
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ec94 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ec94
>> >     .TCP 0x12eda4 timer fired in ESTABLISHED for 609cb55f..609cb5c1
>> 5ae4dacc
>> >     TCP 0x12eda4 TX 46673->80 609cb55f..609cb5c1           5ae4dacc
>>  98 PSH
>> > ACK
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 150 proto 6 id 0402 csum 6131
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ec94 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ec94
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x1305f4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12fdf4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x12eda4 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc
>> 0 SYN
>> > ACK
>> >     ..TCP 0x12eda4 timer fired in ESTABLISHED for 609cb55f..609cb5c1
>> > 5ae4dacc
>> >     TCP 0x12eda4 TX 46673->80 609cb55f..609cb5c1           5ae4dacc
>>  98 PSH
>> > ACK
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 150 proto 6 id 0503 csum 6030
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ec94 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ec94
>> >     ..VIRTIO-NET 0xee704 rx complete iobuf 0x130df4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1305f4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x12eda4 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc
>> 0 SYN
>> > ACK
>> >     .TCP 0x12eda4 timer fired in ESTABLISHED for 609cb55f..609cb5c1
>> 5ae4dacc
>> >     TCP 0x12eda4 TX 46673->80 609cb55f..609cb5c1           5ae4dacc
>>  98 PSH
>> > ACK
>> >     IPv4 TX 10.146.0.10->10.146.0.2 len 150 proto 6 id 0604 csum 5f2f
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x12ec94 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x12ec94
>> >     ......TCP 0x12eda4 timer expired in ESTABLISHED for
>> 609cb55f..609cb5c1
>> > 5ae4dacc
>> >     TCP 0x12eda4 transitioned from ESTABLISHED to CLOSED
>> >     TCP 0x12eda4 connection deleted
>> >      Connection timed out (http://ipxe.org/4c0a6035)
>> >     iPXE> VIRTIO-NET 0xee704 rx complete iobuf 0x1315f4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x130df4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x0 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc    0 SYN
>> ACK
>> >     IPv4 received packet rejected by stack: The socket is not connected
>> > (http://ipxe.org/380a6001)
>> >
>> >     iPXE> VIRTIO-NET 0xee704 rx complete iobuf 0x131df4 len 74
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1315f4 on vq 0
>> >     IPv4 RX 10.146.0.10<-10.146.0.2 len 60 proto 6 id 0000 csum 258d
>> >     TCP 0x0 RX 46673<-80           609cb55f 5ae4dacb..5ae4dacc    0 SYN
>> ACK
>> >     IPv4 received packet rejected by stack: The socket is not connected
>> > (http://ipxe.org/380a6001)
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x1325f4 len 42
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x131df4 on vq 0
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1325f4 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x1325f4
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x132df4 len 62
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1325f4 on vq 0
>> >     IPv4 RX 10.146.0.10<-221.204.224.56 len 48 proto 6 id 6aac csum 167b
>> >     TCP 0x0 RX 22<-2281           0a4bb0cf 3368312b..3368312c    0 SYN
>> >     IPv4 received packet rejected by stack: The socket is not connected
>> > (http://ipxe.org/380a6001)
>> >     VIRTIO-NET 0xee704 rx complete iobuf 0x1335f4 len 42
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x132df4 on vq 0
>> >     VIRTIO-NET 0xee704 enqueuing iobuf 0x1335f4 on vq 1
>> >     VIRTIO-NET 0xee704 tx complete iobuf 0x1335f4
>> >
>> >
>> >
>> > === HTTP server 10.146.0.2 (ws01) ===
>> >
>> >     $ sudo tcpdump host 10.146.0.10
>> >     tcpdump: verbose output suppressed, use -v or -vv for full protocol
>> > decode
>> >     listening on ens4, link-type EN10MB (Ethernet), capture size 262144
>> > bytes
>> >     04:55:43.715483 IP ipxe01.c.suda-main.internal.46673 >
>> > ws01.c.suda-main.internal.http: Flags [S], seq 1620882782, win 65532,
>> > options [nop,nop,TS val 323011 ecr 0,nop,nop,sackOK,nop,wscale 9,mss
>> 1460],
>> > length 0
>> >     04:55:43.715549 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77061640 ecr
>> > 323011,nop,wscale 7], length 0
>> >     04:55:44.712811 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77061890 ecr
>> > 323011,nop,wscale 7], length 0
>> >     04:55:46.712829 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77062390 ecr
>> > 323011,nop,wscale 7], length 0
>> >     04:55:50.712864 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77063390 ecr
>> > 323011,nop,wscale 7], length 0
>> >     04:55:58.712842 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77065390 ecr
>> > 323011,nop,wscale 7], length 0
>> >     04:56:14.712836 IP ws01.c.suda-main.internal.http >
>> > ipxe01.c.suda-main.internal.46673: Flags [S.], seq 1524947659, ack
>> > 1620882783, win 28160, options [mss 1420,sackOK,TS val 77069390 ecr
>> > 323011,nop,wscale 7], length 0
>>
>> Thanks for the logs. Can you please try the following patch? It's a
>> crazy workaround to reinitialize the driver on each transmitted
>> packet. If it works, we'll go from there and try something more
>> sophisticated. Thanks!
>>
>>
>> --- a/src/drivers/net/virtio-net.c
>> +++ b/src/drivers/net/virtio-net.c
>> @@ -345,6 +345,8 @@ static void virtnet_close ( struct net_device *netdev
>> ) {
>>   */
>>  static int virtnet_transmit ( struct net_device *netdev,
>>                               struct io_buffer *iobuf ) {
>> +       virtnet_close ( netdev );
>> +       virtnet_open ( netdev );
>>         virtnet_enqueue_iob ( netdev, TX_INDEX, iobuf );
>>         return 0;
>>  }
>>
>>
>> > 2016-12-14 18:17 GMT+09:00 Ladi Prosek <lprosek at redhat.com>:
>> >>
>> >> Hi Akihiro,
>> >>
>> >> On Wed, Dec 14, 2016 at 8:51 AM, Akihiro Suda <suda.kyoto at gmail.com>
>> >> wrote:
>> >> > Hi Christian,
>> >> >
>> >> > Thank you for the suggestion, I'll try to report this to google.
>> >> >
>> >> > I found that the cause of this issue is because GCE's
>> >> > VIRTIO_PCI_QUEUE_NUM
>> >> > is 4096, which is larger than iPXE's MAX_QUEUE_NUM (256).
>> >> >
>> >> >
>> >> > https://git.ipxe.org/ipxe.git/blob/26050fd4c87c50503d5bd573b
>> 2ec91703676e211:/src/drivers/bus/virtio-pci.c#l43
>> >> >
>> >> > https://git.ipxe.org/ipxe.git/blob/26050fd4c87c50503d5bd573b
>> 2ec91703676e211:/src/include/ipxe/virtio-ring.h#l24
>> >> >
>> >> >
>> >> > IIUC this issue will be resolved if GCE supports virtio 1.0, which
>> would
>> >> > allow iPXE to use custom queue num smaller than the virtio device's
>> max
>> >> > value.
>> >>
>> >> iPXE virtio 1.0 code does not cap the queue size to MAX_QUEUE_NUM. In
>> >> fact, it does not check it against any maximum and still uses
>> >> fixed-sized virtqueue data structures, just like legacy. This is a
>> >> bug.
>> >>
>> >> > However, it would be great if iPXE can support setting MAX_QUEUE_NUM
>> to
>> >> > 4096
>> >> > (via `config/general.h`, probably).
>> >>
>> >> Even better, iPXE should try to use the host provided size in legacy
>> >> mode, i.e. no MAX_QUEUE_NUM needed. The few extra dynamic allocations
>> >> shouldn't hurt anything.
>> >>
>> >> > Actually I tried to set MAX_QUEUE_NUM to 4096 and got
>> >> > virtnet_open_legacy()
>> >> > succeeded, but it still doesn't work:
>> >> >
>> >> >     iPXE> dhcp
>> >> >     DHCP 0x120e44 entering discovery state
>> >> >     Configuring (net0 42:01:0a:92:00:0a)...DHCP 0x120e44 DHCPDISCOVER
>> >> >     DHCP 0x120e44 DHCPOFFER from 169.254.169.254:67 for 10.146.0.10
>> >> >     .DHCP 0x120e44 DHCPDISCOVER
>> >> >     ..DHCP 0x120e44 entering request state
>> >> >     DHCP 0x120e44 DHCPREQUEST to 169.254.169.254:67 for 10.146.0.10
>> >> >     DHCP 0x120e44 DHCPREQUEST to 169.254.169.254:67 for 10.146.0.10
>> >> >     .DHCP 0x120e44 DHCPREQUEST to 169.254.169.254:67 for 10.146.0.10
>> >> >     .DHCP 0x120e44 DHCPREQUEST to 169.254.169.254:67 for 10.146.0.10
>> >> >     ...DHCP 0x120e44 DHCPREQUEST to 169.254.169.254:67 for
>> 10.146.0.10
>> >> >     ....... No configuration methods succeeded
>> >> > (http://ipxe.org/040ee119)
>> >> >     iPXE>
>> >> >
>> >> > I haven't captured DHCP packets (because I'm unsure how to do so in
>> >> > GCE's
>> >> > fully managed DHCP server), but I guess DHCPACK is actually sent from
>> >> > the
>> >> > DHCP server but somehow iPXE missed it.
>> >>
>> >> Do you see any interesting log output with DEBUG=virtio-net,virtio-pci
>> ?
>> >>
>> >> > I'd appreciate if anyone can support me to set MAX_QUEUE_NUM to 4096.
>> >>
>> >> I'll look into it. My proposal is to keep using 128 as the cap in
>> >> virtio 1.0 and support any queue size in legacy, only subject to
>> >> available memory.
>> >>
>> >> > 2016-12-14 16:19 GMT+09:00 Christian Nilsson <nikize at gmail.com>:
>> >> >>
>> >> >> You might want to report this to google as well if you haven't
>> already.
>> >> >>
>> >> >> On Wed, Dec 14, 2016 at 7:16 AM, Akihiro Suda <suda.kyoto at gmail.com
>> >
>> >> >> wrote:
>> >> >> > Hello,
>> >> >> >
>> >> >> > I tried to boot iPXE on a Google Compute Engine instance, but the
>> >> >> > virtio
>> >> >> > driver doesn't work because virtnet_open_legacy() fails to find
>> >> >> > virtqueues.
>> >> >> >
>> >> >> > Please let me know what I can do for providing further
>> information to
>> >> >> > debug
>> >> >> > the issue.
>> >> >> >
>> >> >> > The serial console output with "DEBUG=virtio-net" is as follows:
>> >> >> >
>> >> >> >     iPXE initialising devices...Common virtio capability not
>> found!
>> >> >> >     VIRTIO-NET 0xdf584 busaddr=0000:00:04.0 ioaddr=0xc040 irq=11
>> >> >> >     VIRTIO-NET 0xdf584 mac=42:01:0a:92:00:0a
>> >> >> >     ok
>> >> >> >
>> >> >> >     iPXE 1.0.0+ (26050) -- Open Source Network Boot Firmware --
>> >> >> > http://ipxe.org
>> >> >> >     Features: DNS HTTP iSCSI TFTP SRP AoE ELF MBOOT PXE bzImage
>> Menu
>> >> >> > PXEXT
>> >> >> >     iPXE> ifstat
>> >> >> >     net0: 42:01:0a:92:00:0a using virtio-net on 0000:00:04.0
>> (closed)
>> >> >> >       [Link:up, TX:0 TXE:0 RX:0 RXE:0]
>> >> >> >     iPXE> dhcp
>> >> >> >     VIRTIO-NET 0xdf584 cannot register queue 0
>> >> >> >     Could not open net0: No such file or directory
>> >> >> > (http://ipxe.org/2d5c403b)
>> >> >> >     iPXE>
>> >> >> >
>> >> >> >
>> >> >> > This ENOENT is raised from virtnet_open_legacy():
>> >> >> >
>> >> >> >
>> >> >> > https://git.ipxe.org/ipxe.git/blob/26050fd4c87c50503d5bd573b
>> 2ec91703676e211:/src/drivers/net/virtio-net.c#l205
>> >> >> >
>> >> >> >
>> >> >> > I also tested some previous commits, but all of them failed, so
>> the
>> >> >> > issue is
>> >> >> > not a regression in some recent commit:
>> >> >> >
>> >> >> >  * 26050fd (Dec  8, 2016): the last commit when I tested
>> >> >> >  * 7b499f8 (Apr 11, 2016): the last commit without support for
>> virtio
>> >> >> > 1.0
>> >> >> >  * e4419ff (Jul  2, 2010):  the first commit with the "native iPXE
>> >> >> > driver"
>> >> >> > (The commit date is older than 232c208, but actually newer than
>> >> >> > 232c208)
>> >> >> >  * 232c208 (Jul 11, 2010): the last commit without the "native
>> iPXE
>> >> >> > driver".
>> >> >> > The error message is "ERROR: queue size 4096 > 512", "Cannot
>> register
>> >> >> > queue
>> >> >> > #0"
>> >> >> >
>> >> >> >
>> >> >> > Regards,
>> >> >> >
>> >> >> > Akihiro Suda
>> >> >> >
>> >> >> >
>> >> >> > _______________________________________________
>> >> >> > ipxe-devel mailing list
>> >> >> > ipxe-devel at lists.ipxe.org
>> >> >> > https://lists.ipxe.org/mailman/listinfo.cgi/ipxe-devel
>> >> >> >
>> >> >
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > ipxe-devel mailing list
>> >> > ipxe-devel at lists.ipxe.org
>> >> > https://lists.ipxe.org/mailman/listinfo.cgi/ipxe-devel
>> >> >
>> >
>> >
>>
>
>
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