RE: [PATCH 2/3] hv_netvsc: Wait for completion on request NVSP_MSG4_TYPE_SWITCH_DATA_PATH
From: Long Li
Date: Wed Jan 06 2021 - 19:00:58 EST
> Subject: Re: [PATCH 2/3] hv_netvsc: Wait for completion on request
> NVSP_MSG4_TYPE_SWITCH_DATA_PATH
>
> Hi Long,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on linus/master] [also build test WARNING on
> v5.11-rc2 next-20210104] [If your patch is applied to the wrong git tree, kindly
> drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit-
> scm.com%2Fdocs%2Fgit-format-
> patch&data=04%7C01%7Clongli%40microsoft.com%7C695cf3d454eb468
> b85fb08d8b1fb3ddd%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6
> 37455042608743102%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMD
> AiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=
> 90AgH9HlZumRZ4UNC4uD2WIRpZ6ZEnvIdOKOfzYcXpI%3D&reserved=0]
>
> url:
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2F0day-ci%2Flinux%2Fcommits%2FLong-Li%2Fhv_netvsc-Check-VF-
> datapath-when-sending-traffic-to-VF%2F20210106-
> 092237&data=04%7C01%7Clongli%40microsoft.com%7C695cf3d454eb46
> 8b85fb08d8b1fb3ddd%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C
> 637455042608753098%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwM
> DAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata
> =vtVJ8pXIOxIYeKdaqT9pD1%2BEuOM3wz4yqsHh8uWsGP4%3D&reserv
> ed=0
> base:
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.k
> ernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git&
> amp;data=04%7C01%7Clongli%40microsoft.com%7C695cf3d454eb468b85fb0
> 8d8b1fb3ddd%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C6374550
> 42608753098%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQ
> IjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=FXMG
> CFODFoq3KLklxr17iVHiq%2FWmJ3c0fM7vIZRfNmc%3D&reserved=0
> e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62
> config: i386-allyesconfig (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> reproduce (this is a W=1 build):
> #
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2F0day-
> ci%2Flinux%2Fcommit%2F8c92b5574da1b0c2aee3eab7da2c4dad8d92572c&a
> mp;data=04%7C01%7Clongli%40microsoft.com%7C695cf3d454eb468b85fb08
> d8b1fb3ddd%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63745504
> 2608753098%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIj
> oiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=MMXkQ
> KENGpyfW0NJs2khBSKTuBExFSZaWHgWyyIj6UU%3D&reserved=0
> git remote add linux-review
> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgith
> ub.com%2F0day-
> ci%2Flinux&data=04%7C01%7Clongli%40microsoft.com%7C695cf3d454e
> b468b85fb08d8b1fb3ddd%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0
> %7C637455042608753098%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjA
> wMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&s
> data=uge6PX2NyAe%2BjRtvgOhR5xzN2ltBctZXeZwn0hoYco0%3D&reser
> ved=0
> git fetch --no-tags linux-review Long-Li/hv_netvsc-Check-VF-datapath-
> when-sending-traffic-to-VF/20210106-092237
> git checkout 8c92b5574da1b0c2aee3eab7da2c4dad8d92572c
> # save the attached .config to linux build tree
> make W=1 ARCH=i386
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> All warnings (new ones prefixed by >>):
>
> drivers/net/hyperv/netvsc.c: In function 'netvsc_send_completion':
> >> drivers/net/hyperv/netvsc.c:778:14: warning: cast to pointer from
> >> integer of different size [-Wint-to-pointer-cast]
> 778 | pkt_rqst = (struct nvsp_message *)cmd_rqst;
> | ^
I think this warning can be safely ignored.
When sending packets over vmbus, the address is passed as u64 and stored internally as u64 in vmbus_next_request_id(). Passing a 32 bit address will not lose any data. Later the address is retrieved from vmbus_request_addr() as a u64. Again, it will not lose data when casting to a 32 bit address.
This method of storing and retrieving addresses are used throughout other hyper-v drivers. If we want to not to trigger this warning, I suggest making a patch to convert all those usages in all hyper-v drivers.
Thanks,
Long
>
>
> vim +778 drivers/net/hyperv/netvsc.c
>
> 757
> 758 static void netvsc_send_completion(struct net_device *ndev,
> 759 struct netvsc_device *net_device,
> 760 struct vmbus_channel
> *incoming_channel,
> 761 const struct vmpacket_descriptor
> *desc,
> 762 int budget)
> 763 {
> 764 const struct nvsp_message *nvsp_packet =
> hv_pkt_data(desc);
> 765 u32 msglen = hv_pkt_datalen(desc);
> 766 struct nvsp_message *pkt_rqst;
> 767 u64 cmd_rqst;
> 768
> 769 /* First check if this is a VMBUS completion without data
> payload */
> 770 if (!msglen) {
> 771 cmd_rqst =
> vmbus_request_addr(&incoming_channel->requestor,
> 772 (u64)desc->trans_id);
> 773 if (cmd_rqst == VMBUS_RQST_ERROR) {
> 774 netdev_err(ndev, "Invalid transaction id\n");
> 775 return;
> 776 }
> 777
> > 778 pkt_rqst = (struct nvsp_message *)cmd_rqst;
> 779 switch (pkt_rqst->hdr.msg_type) {
> 780 case NVSP_MSG4_TYPE_SWITCH_DATA_PATH:
> 781 complete(&net_device->channel_init_wait);
> 782 break;
> 783
> 784 default:
> 785 netdev_err(ndev, "Unexpected VMBUS
> completion!!\n");
> 786 }
> 787 return;
> 788 }
> 789
> 790 /* Ensure packet is big enough to read header fields */
> 791 if (msglen < sizeof(struct nvsp_message_header)) {
> 792 netdev_err(ndev, "nvsp_message length too
> small: %u\n", msglen);
> 793 return;
> 794 }
> 795
> 796 switch (nvsp_packet->hdr.msg_type) {
> 797 case NVSP_MSG_TYPE_INIT_COMPLETE:
> 798 if (msglen < sizeof(struct nvsp_message_header) +
> 799 sizeof(struct
> nvsp_message_init_complete)) {
> 800 netdev_err(ndev, "nvsp_msg length too
> small: %u\n",
> 801 msglen);
> 802 return;
> 803 }
> 804 fallthrough;
> 805
> 806 case NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE:
> 807 if (msglen < sizeof(struct nvsp_message_header) +
> 808 sizeof(struct
> nvsp_1_message_send_receive_buffer_complete)) {
> 809 netdev_err(ndev, "nvsp_msg1 length too
> small: %u\n",
> 810 msglen);
> 811 return;
> 812 }
> 813 fallthrough;
> 814
> 815 case NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE:
> 816 if (msglen < sizeof(struct nvsp_message_header) +
> 817 sizeof(struct
> nvsp_1_message_send_send_buffer_complete)) {
> 818 netdev_err(ndev, "nvsp_msg1 length too
> small: %u\n",
> 819 msglen);
> 820 return;
> 821 }
> 822 fallthrough;
> 823
> 824 case NVSP_MSG5_TYPE_SUBCHANNEL:
> 825 if (msglen < sizeof(struct nvsp_message_header) +
> 826 sizeof(struct
> nvsp_5_subchannel_complete)) {
> 827 netdev_err(ndev, "nvsp_msg5 length too
> small: %u\n",
> 828 msglen);
> 829 return;
> 830 }
> 831 /* Copy the response back */
> 832 memcpy(&net_device->channel_init_pkt,
> nvsp_packet,
> 833 sizeof(struct nvsp_message));
> 834 complete(&net_device->channel_init_wait);
> 835 break;
> 836
> 837 case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
> 838 netvsc_send_tx_complete(ndev, net_device,
> incoming_channel,
> 839 desc, budget);
> 840 break;
> 841
> 842 default:
> 843 netdev_err(ndev,
> 844 "Unknown send completion type %d
> received!!\n",
> 845 nvsp_packet->hdr.msg_type);
> 846 }
> 847 }
> 848
>
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
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> %7C0%7C637455042608753098%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC
> 4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&
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