linux-stable.git/drivers/net/hyperv, branch linux-5.8.y Linux kernel stable tree hv_netvsc: Cache the current data path to avoid duplicate call and message 2020-10-07T06:02:48+00:00 Dexuan Cui decui@microsoft.com 2020-09-09T04:08:19+00:00 9c524f9df9c7afec25995f4f973b7aa742412cdd [ Upstream commit da26658c3d7005aa67a706dceff7b2807b59e123 ] The previous change "hv_netvsc: Switch the data path at the right time during hibernation" adds the call of netvsc_vf_changed() upon NETDEV_CHANGE, so it's necessary to avoid the duplicate call and message when the VF is brought UP or DOWN. Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit da26658c3d7005aa67a706dceff7b2807b59e123 ]

The previous change "hv_netvsc: Switch the data path at the right time
during hibernation" adds the call of netvsc_vf_changed() upon
NETDEV_CHANGE, so it's necessary to avoid the duplicate call and message
when the VF is brought UP or DOWN.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
hv_netvsc: Switch the data path at the right time during hibernation 2020-10-01T15:36:28+00:00 Dexuan Cui decui@microsoft.com 2020-09-09T04:07:32+00:00 a634ff2bb06a4e3a57ec887f1a3e290c9044aba1 [ Upstream commit de214e52de1bba5392b5b7054924a08dbd57c2f6 ] When netvsc_resume() is called, the mlx5 VF NIC has not been resumed yet, so in the future the host might sliently fail the call netvsc_vf_changed() -> netvsc_switch_datapath() there, even if the call works now. Call netvsc_vf_changed() in the NETDEV_CHANGE event handler: at that time the mlx5 VF NIC has been resumed. Fixes: 19162fd4063a ("hv_netvsc: Fix hibernation for mlx5 VF driver") Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit de214e52de1bba5392b5b7054924a08dbd57c2f6 ]

When netvsc_resume() is called, the mlx5 VF NIC has not been resumed yet,
so in the future the host might sliently fail the call netvsc_vf_changed()
-> netvsc_switch_datapath() there, even if the call works now.

Call netvsc_vf_changed() in the NETDEV_CHANGE event handler: at that time
the mlx5 VF NIC has been resumed.

Fixes: 19162fd4063a ("hv_netvsc: Fix hibernation for mlx5 VF driver")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
hv_netvsc: Fix hibernation for mlx5 VF driver 2020-09-26T16:05:27+00:00 Dexuan Cui decui@microsoft.com 2020-09-07T07:13:39+00:00 150feba39d809c37a3e95f8802c0219237936371 [ Upstream commit 19162fd4063a3211843b997a454b505edb81d5ce ] mlx5_suspend()/resume() keep the network interface, so during hibernation netvsc_unregister_vf() and netvsc_register_vf() are not called, and hence netvsc_resume() should call netvsc_vf_changed() to switch the data path back to the VF after hibernation. Note: after we close and re-open the vmbus channel of the netvsc NIC in netvsc_suspend() and netvsc_resume(), the data path is implicitly switched to the netvsc NIC. Similarly, netvsc_suspend() should not call netvsc_unregister_vf(), otherwise the VF can no longer be used after hibernation. For mlx4, since the VF network interafce is explicitly destroyed and re-created during hibernation (see mlx4_suspend()/resume()), hv_netvsc already explicitly switches the data path from and to the VF automatically via netvsc_register_vf() and netvsc_unregister_vf(), so mlx4 doesn't need this fix. Note: mlx4 can still work with the fix because in netvsc_suspend()/resume() ndev_ctx->vf_netdev is NULL for mlx4. Fixes: 0efeea5fb153 ("hv_netvsc: Add the support of hibernation") Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 19162fd4063a3211843b997a454b505edb81d5ce ]

mlx5_suspend()/resume() keep the network interface, so during hibernation
netvsc_unregister_vf() and netvsc_register_vf() are not called, and hence
netvsc_resume() should call netvsc_vf_changed() to switch the data path
back to the VF after hibernation. Note: after we close and re-open the
vmbus channel of the netvsc NIC in netvsc_suspend() and netvsc_resume(),
the data path is implicitly switched to the netvsc NIC. Similarly,
netvsc_suspend() should not call netvsc_unregister_vf(), otherwise the VF
can no longer be used after hibernation.

For mlx4, since the VF network interafce is explicitly destroyed and
re-created during hibernation (see mlx4_suspend()/resume()), hv_netvsc
already explicitly switches the data path from and to the VF automatically
via netvsc_register_vf() and netvsc_unregister_vf(), so mlx4 doesn't need
this fix. Note: mlx4 can still work with the fix because in
netvsc_suspend()/resume() ndev_ctx->vf_netdev is NULL for mlx4.

Fixes: 0efeea5fb153 ("hv_netvsc: Add the support of hibernation")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hv_netvsc: Remove "unlikely" from netvsc_select_queue 2020-09-23T10:59:49+00:00 Haiyang Zhang haiyangz@microsoft.com 2020-08-20T21:53:14+00:00 0fb2de68a876af1c1ae8f3943dc1a70f0b020d45 commit 4d820543c54c47a2bd3c95ddbf52f83c89a219a0 upstream. When using vf_ops->ndo_select_queue, the number of queues of VF is usually bigger than the synthetic NIC. This condition may happen often. Remove "unlikely" from the comparison of ndev->real_num_tx_queues. Fixes: b3bf5666a510 ("hv_netvsc: defer queue selection to VF") Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4d820543c54c47a2bd3c95ddbf52f83c89a219a0 upstream.

When using vf_ops->ndo_select_queue, the number of queues of VF is
usually bigger than the synthetic NIC. This condition may happen
often.
Remove "unlikely" from the comparison of ndev->real_num_tx_queues.

Fixes: b3bf5666a510 ("hv_netvsc: defer queue selection to VF")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hv_netvsc: Fix the queue_mapping in netvsc_vf_xmit() 2020-08-26T09:49:18+00:00 Haiyang Zhang haiyangz@microsoft.com 2020-08-20T21:53:15+00:00 0c831e9dad9defeb4129369e2ddc53af8bc8c33a [ Upstream commit c3d897e01aef8ddc43149e4d661b86f823e3aae7 ] netvsc_vf_xmit() / dev_queue_xmit() will call VF NIC’s ndo_select_queue or netdev_pick_tx() again. They will use skb_get_rx_queue() to get the queue number, so the “skb->queue_mapping - 1” will be used. This may cause the last queue of VF not been used. Use skb_record_rx_queue() here, so that the skb_get_rx_queue() called later will get the correct queue number, and VF will be able to use all queues. Fixes: b3bf5666a510 ("hv_netvsc: defer queue selection to VF") Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c3d897e01aef8ddc43149e4d661b86f823e3aae7 ]

netvsc_vf_xmit() / dev_queue_xmit() will call VF NIC’s ndo_select_queue
or netdev_pick_tx() again. They will use skb_get_rx_queue() to get the
queue number, so the “skb->queue_mapping - 1” will be used. This may
cause the last queue of VF not been used.

Use skb_record_rx_queue() here, so that the skb_get_rx_queue() called
later will get the correct queue number, and VF will be able to use
all queues.

Fixes: b3bf5666a510 ("hv_netvsc: defer queue selection to VF")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
hv_netvsc: do not use VF device if link is down 2020-08-19T06:26:56+00:00 Stephen Hemminger stephen@networkplumber.org 2020-08-04T16:54:15+00:00 b187671275ac312fb47271388b225369dd02b3dd [ Upstream commit 7c9864bbccc23e1812ac82966555d68c13ea4006 ] If the accelerated networking SRIOV VF device has lost carrier use the synthetic network device which is available as backup path. This is a rare case since if VF link goes down, normally the VMBus device will also loose external connectivity as well. But if the communication is between two VM's on the same host the VMBus device will still work. Reported-by: "Shah, Ashish N" <ashish.n.shah@intel.com> Fixes: 0c195567a8f6 ("netvsc: transparent VF management") Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7c9864bbccc23e1812ac82966555d68c13ea4006 ]

If the accelerated networking SRIOV VF device has lost carrier
use the synthetic network device which is available as backup
path. This is a rare case since if VF link goes down, normally
the VMBus device will also loose external connectivity as well.
But if the communication is between two VM's on the same host
the VMBus device will still work.

Reported-by: "Shah, Ashish N" <ashish.n.shah@intel.com>
Fixes: 0c195567a8f6 ("netvsc: transparent VF management")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2020-06-03T23:27:18+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-06-03T23:27:18+00:00 cb8e59cc87201af93dfbb6c3dccc8fcad72a09c2 Pull networking updates from David Miller: 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz Augusto von Dentz. 2) Add GSO partial support to igc, from Sasha Neftin. 3) Several cleanups and improvements to r8169 from Heiner Kallweit. 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a device self-test. From Andrew Lunn. 5) Start moving away from custom driver versions, use the globally defined kernel version instead, from Leon Romanovsky. 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin. 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet. 8) Add sriov and vf support to hinic, from Luo bin. 9) Support Media Redundancy Protocol (MRP) in the bridging code, from Horatiu Vultur. 10) Support netmap in the nft_nat code, from Pablo Neira Ayuso. 11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina Dubroca. Also add ipv6 support for espintcp. 12) Lots of ReST conversions of the networking documentation, from Mauro Carvalho Chehab. 13) Support configuration of ethtool rxnfc flows in bcmgenet driver, from Doug Berger. 14) Allow to dump cgroup id and filter by it in inet_diag code, from Dmitry Yakunin. 15) Add infrastructure to export netlink attribute policies to userspace, from Johannes Berg. 16) Several optimizations to sch_fq scheduler, from Eric Dumazet. 17) Fallback to the default qdisc if qdisc init fails because otherwise a packet scheduler init failure will make a device inoperative. From Jesper Dangaard Brouer. 18) Several RISCV bpf jit optimizations, from Luke Nelson. 19) Correct the return type of the ->ndo_start_xmit() method in several drivers, it's netdev_tx_t but many drivers were using 'int'. From Yunjian Wang. 20) Add an ethtool interface for PHY master/slave config, from Oleksij Rempel. 21) Add BPF iterators, from Yonghang Song. 22) Add cable test infrastructure, including ethool interfaces, from Andrew Lunn. Marvell PHY driver is the first to support this facility. 23) Remove zero-length arrays all over, from Gustavo A. R. Silva. 24) Calculate and maintain an explicit frame size in XDP, from Jesper Dangaard Brouer. 25) Add CAP_BPF, from Alexei Starovoitov. 26) Support terse dumps in the packet scheduler, from Vlad Buslov. 27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei. 28) Add devm_register_netdev(), from Bartosz Golaszewski. 29) Minimize qdisc resets, from Cong Wang. 30) Get rid of kernel_getsockopt and kernel_setsockopt in order to eliminate set_fs/get_fs calls. From Christoph Hellwig. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits) selftests: net: ip_defrag: ignore EPERM net_failover: fixed rollback in net_failover_open() Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv" Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv" vmxnet3: allow rx flow hash ops only when rss is enabled hinic: add set_channels ethtool_ops support selftests/bpf: Add a default $(CXX) value tools/bpf: Don't use $(COMPILE.c) bpf, selftests: Use bpf_probe_read_kernel s390/bpf: Use bcr 0,%0 as tail call nop filler s390/bpf: Maintain 8-byte stack alignment selftests/bpf: Fix verifier test selftests/bpf: Fix sample_cnt shared between two threads bpf, selftests: Adapt cls_redirect to call csum_level helper bpf: Add csum_level helper for fixing up csum levels bpf: Fix up bpf_skb_adjust_room helper's skb csum setting sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf() crypto/chtls: IPv6 support for inline TLS Crypto/chcr: Fixes a coccinile check error Crypto/chcr: Fixes compilations warnings ... 
Pull networking updates from David Miller:

 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz
    Augusto von Dentz.

 2) Add GSO partial support to igc, from Sasha Neftin.

 3) Several cleanups and improvements to r8169 from Heiner Kallweit.

 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a
    device self-test. From Andrew Lunn.

 5) Start moving away from custom driver versions, use the globally
    defined kernel version instead, from Leon Romanovsky.

 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin.

 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet.

 8) Add sriov and vf support to hinic, from Luo bin.

 9) Support Media Redundancy Protocol (MRP) in the bridging code, from
    Horatiu Vultur.

10) Support netmap in the nft_nat code, from Pablo Neira Ayuso.

11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina
    Dubroca. Also add ipv6 support for espintcp.

12) Lots of ReST conversions of the networking documentation, from Mauro
    Carvalho Chehab.

13) Support configuration of ethtool rxnfc flows in bcmgenet driver,
    from Doug Berger.

14) Allow to dump cgroup id and filter by it in inet_diag code, from
    Dmitry Yakunin.

15) Add infrastructure to export netlink attribute policies to
    userspace, from Johannes Berg.

16) Several optimizations to sch_fq scheduler, from Eric Dumazet.

17) Fallback to the default qdisc if qdisc init fails because otherwise
    a packet scheduler init failure will make a device inoperative. From
    Jesper Dangaard Brouer.

18) Several RISCV bpf jit optimizations, from Luke Nelson.

19) Correct the return type of the ->ndo_start_xmit() method in several
    drivers, it's netdev_tx_t but many drivers were using
    'int'. From Yunjian Wang.

20) Add an ethtool interface for PHY master/slave config, from Oleksij
    Rempel.

21) Add BPF iterators, from Yonghang Song.

22) Add cable test infrastructure, including ethool interfaces, from
    Andrew Lunn. Marvell PHY driver is the first to support this
    facility.

23) Remove zero-length arrays all over, from Gustavo A. R. Silva.

24) Calculate and maintain an explicit frame size in XDP, from Jesper
    Dangaard Brouer.

25) Add CAP_BPF, from Alexei Starovoitov.

26) Support terse dumps in the packet scheduler, from Vlad Buslov.

27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei.

28) Add devm_register_netdev(), from Bartosz Golaszewski.

29) Minimize qdisc resets, from Cong Wang.

30) Get rid of kernel_getsockopt and kernel_setsockopt in order to
    eliminate set_fs/get_fs calls. From Christoph Hellwig.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits)
  selftests: net: ip_defrag: ignore EPERM
  net_failover: fixed rollback in net_failover_open()
  Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv"
  Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"
  vmxnet3: allow rx flow hash ops only when rss is enabled
  hinic: add set_channels ethtool_ops support
  selftests/bpf: Add a default $(CXX) value
  tools/bpf: Don't use $(COMPILE.c)
  bpf, selftests: Use bpf_probe_read_kernel
  s390/bpf: Use bcr 0,%0 as tail call nop filler
  s390/bpf: Maintain 8-byte stack alignment
  selftests/bpf: Fix verifier test
  selftests/bpf: Fix sample_cnt shared between two threads
  bpf, selftests: Adapt cls_redirect to call csum_level helper
  bpf: Add csum_level helper for fixing up csum levels
  bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
  sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
  crypto/chtls: IPv6 support for inline TLS
  Crypto/chcr: Fixes a coccinile check error
  Crypto/chcr: Fixes compilations warnings
  ...
Merge tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux 2020-06-03T22:00:05+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-06-03T22:00:05+00:00 6b2591c21273ebf65c13dae5d260ce88f0f197dd Pull hyper-v updates from Wei Liu: - a series from Andrea to support channel reassignment - a series from Vitaly to clean up Vmbus message handling - a series from Michael to clean up and augment hyperv-tlfs.h - patches from Andy to clean up GUID usage in Hyper-V code - a few other misc patches * tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (29 commits) Drivers: hv: vmbus: Resolve more races involving init_vp_index() Drivers: hv: vmbus: Resolve race between init_vp_index() and CPU hotplug vmbus: Replace zero-length array with flexible-array Driver: hv: vmbus: drop a no long applicable comment hyper-v: Switch to use UUID types directly hyper-v: Replace open-coded variant of %*phN specifier hyper-v: Supply GUID pointer to printf() like functions hyper-v: Use UUID API for exporting the GUID (part 2) asm-generic/hyperv: Add definitions for Get/SetVpRegister hypercalls x86/hyperv: Split hyperv-tlfs.h into arch dependent and independent files x86/hyperv: Remove HV_PROCESSOR_POWER_STATE #defines KVM: x86: hyperv: Remove duplicate definitions of Reference TSC Page drivers: hv: remove redundant assignment to pointer primary_channel scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal hv_utils: Always execute the fcopy and vss callbacks in a tasklet ... 
Pull hyper-v updates from Wei Liu:

 - a series from Andrea to support channel reassignment

 - a series from Vitaly to clean up Vmbus message handling

 - a series from Michael to clean up and augment hyperv-tlfs.h

 - patches from Andy to clean up GUID usage in Hyper-V code

 - a few other misc patches

* tag 'hyperv-next-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (29 commits)
  Drivers: hv: vmbus: Resolve more races involving init_vp_index()
  Drivers: hv: vmbus: Resolve race between init_vp_index() and CPU hotplug
  vmbus: Replace zero-length array with flexible-array
  Driver: hv: vmbus: drop a no long applicable comment
  hyper-v: Switch to use UUID types directly
  hyper-v: Replace open-coded variant of %*phN specifier
  hyper-v: Supply GUID pointer to printf() like functions
  hyper-v: Use UUID API for exporting the GUID (part 2)
  asm-generic/hyperv: Add definitions for Get/SetVpRegister hypercalls
  x86/hyperv: Split hyperv-tlfs.h into arch dependent and independent files
  x86/hyperv: Remove HV_PROCESSOR_POWER_STATE #defines
  KVM: x86: hyperv: Remove duplicate definitions of Reference TSC Page
  drivers: hv: remove redundant assignment to pointer primary_channel
  scsi: storvsc: Re-init stor_chns when a channel interrupt is re-assigned
  Drivers: hv: vmbus: Introduce the CHANNELMSG_MODIFYCHANNEL message type
  Drivers: hv: vmbus: Synchronize init_vp_index() vs. CPU hotplug
  Drivers: hv: vmbus: Remove the unused HV_LOCALIZED channel affinity logic
  PCI: hv: Prepare hv_compose_msi_msg() for the VMBus-channel-interrupt-to-vCPU reassignment functionality
  Drivers: hv: vmbus: Use a spin lock for synchronizing channel scheduling vs. channel removal
  hv_utils: Always execute the fcopy and vss callbacks in a tasklet
  ...
xsk: Remove MEM_TYPE_ZERO_COPY and corresponding code 2020-05-22T00:31:27+00:00 Björn Töpel bjorn.topel@intel.com 2020-05-20T19:21:00+00:00 0807892ecb35734b7ce6f7c29b078f1b60151c94 There are no users of MEM_TYPE_ZERO_COPY. Remove all corresponding code, including the "handle" member of struct xdp_buff. rfc->v1: Fixed spelling in commit message. (Björn) Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com 
There are no users of MEM_TYPE_ZERO_COPY. Remove all corresponding
code, including the "handle" member of struct xdp_buff.

rfc->v1: Fixed spelling in commit message. (Björn)

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com
hv_netvsc: Add XDP frame size to driver 2020-05-15T04:21:54+00:00 Jesper Dangaard Brouer brouer@redhat.com 2020-05-14T10:49:58+00:00 7358877ac11041a22ce1cb35c352809051eac48f The hyperv NIC driver does memory allocation and copy even without XDP. In XDP mode it will allocate a new page for each packet and copy over the payload, before invoking the XDP BPF-prog. The positive thing it that its easy to determine the xdp.frame_sz. The XDP implementation for hv_netvsc transparently passes xdp_prog to the associated VF NIC. Many of the Azure VMs are using SRIOV, so majority of the data are actually processed directly on the VF driver's XDP path. So the overhead of the synthetic data path (hv_netvsc) is minimal. Then XDP is enabled on this driver, XDP_PASS and XDP_TX will create the SKB via build_skb (based on the newly allocated page). Now using XDP frame_sz this will provide more skb_tailroom, which netstack can use for SKB coalescing (e.g tcp_try_coalesce -> skb_try_coalesce). V3: Adjust patch desc to be more positive. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: Wei Liu <wei.liu@kernel.org> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Link: https://lore.kernel.org/bpf/158945339857.97035.10212138582505736163.stgit@firesoul 
The hyperv NIC driver does memory allocation and copy even without XDP.
In XDP mode it will allocate a new page for each packet and copy over
the payload, before invoking the XDP BPF-prog.

The positive thing it that its easy to determine the xdp.frame_sz.

The XDP implementation for hv_netvsc transparently passes xdp_prog
to the associated VF NIC. Many of the Azure VMs are using SRIOV, so
majority of the data are actually processed directly on the VF driver's XDP
path. So the overhead of the synthetic data path (hv_netvsc) is minimal.

Then XDP is enabled on this driver, XDP_PASS and XDP_TX will create the
SKB via build_skb (based on the newly allocated page). Now using XDP
frame_sz this will provide more skb_tailroom, which netstack can use for
SKB coalescing (e.g tcp_try_coalesce -> skb_try_coalesce).

V3: Adjust patch desc to be more positive.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Link: https://lore.kernel.org/bpf/158945339857.97035.10212138582505736163.stgit@firesoul