hv_netvsc: Remove rmsg_pgcnt

init_page_array() now always creates a single page buffer array entry
for the rndis message, even if the rndis message crosses a page
boundary. As such, the number of pa

hv_netvsc: Remove rmsg_pgcnt

init_page_array() now always creates a single page buffer array entry
for the rndis message, even if the rndis message crosses a page
boundary. As such, the number of page buffer array entries used for
the rndis message must no longer be tracked -- it is always just 1.
Remove the rmsg_pgcnt field and use "1" where the value is needed.

Cc: <[email protected]> # 6.1.x
Signed-off-by: Michael Kelley <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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hv_netvsc: Preserve contiguous PFN grouping in the page buffer array

Starting with commit dca5161f9bd0 ("hv_netvsc: Check status in
SEND_RNDIS_PKT completion message") in the 6.3 kernel, the Linux
d

hv_netvsc: Preserve contiguous PFN grouping in the page buffer array

Starting with commit dca5161f9bd0 ("hv_netvsc: Check status in
SEND_RNDIS_PKT completion message") in the 6.3 kernel, the Linux
driver for Hyper-V synthetic networking (netvsc) occasionally reports
"nvsp_rndis_pkt_complete error status: 2".[1] This error indicates
that Hyper-V has rejected a network packet transmit request from the
guest, and the outgoing network packet is dropped. Higher level
network protocols presumably recover and resend the packet so there is
no functional error, but performance is slightly impacted. Commit
dca5161f9bd0 is not the cause of the error -- it only added reporting
of an error that was already happening without any notice. The error
has presumably been present since the netvsc driver was originally
introduced into Linux.

The root cause of the problem is that the netvsc driver in Linux may
send an incorrectly formatted VMBus message to Hyper-V when
transmitting the network packet. The incorrect formatting occurs when
the rndis header of the VMBus message crosses a page boundary due to
how the Linux skb head memory is aligned. In such a case, two PFNs are
required to describe the location of the rndis header, even though
they are contiguous in guest physical address (GPA) space. Hyper-V
requires that two rndis header PFNs be in a single "GPA range" data
struture, but current netvsc code puts each PFN in its own GPA range,
which Hyper-V rejects as an error.

The incorrect formatting occurs only for larger packets that netvsc
must transmit via a VMBus "GPA Direct" message. There's no problem
when netvsc transmits a smaller packet by copying it into a pre-
allocated send buffer slot because the pre-allocated slots don't have
page crossing issues.

After commit 14ad6ed30a10 ("net: allow small head cache usage with
large MAX_SKB_FRAGS values") in the 6.14-rc4 kernel, the error occurs
much more frequently in VMs with 16 or more vCPUs. It may occur every
few seconds, or even more frequently, in an ssh session that outputs a
lot of text. Commit 14ad6ed30a10 subtly changes how skb head memory is
allocated, making it much more likely that the rndis header will cross
a page boundary when the vCPU count is 16 or more. The changes in
commit 14ad6ed30a10 are perfectly valid -- they just had the side
effect of making the netvsc bug more prominent.

Current code in init_page_array() creates a separate page buffer array
entry for each PFN required to identify the data to be transmitted.
Contiguous PFNs get separate entries in the page buffer array, and any
information about contiguity is lost.

Fix the core issue by having init_page_array() construct the page
buffer array to represent contiguous ranges rather than individual
pages. When these ranges are subsequently passed to
netvsc_build_mpb_array(), it can build GPA ranges that contain
multiple PFNs, as required to avoid the error "nvsp_rndis_pkt_complete
error status: 2". If instead the network packet is sent by copying
into a pre-allocated send buffer slot, the copy proceeds using the
contiguous ranges rather than individual pages, but the result of the
copying is the same. Also fix rndis_filter_send_request() to construct
a contiguous range, since it has its own page buffer array.

This change has a side benefit in CoCo VMs in that netvsc_dma_map()
calls dma_map_single() on each contiguous range instead of on each
page. This results in fewer calls to dma_map_single() but on larger
chunks of memory, which should reduce contention on the swiotlb.

Since the page buffer array now contains one entry for each contiguous
range instead of for each individual page, the number of entries in
the array can be reduced, saving 208 bytes of stack space in
netvsc_xmit() when MAX_SKG_FRAGS has the default value of 17.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=217503

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217503
Cc: <[email protected]> # 6.1.x
Signed-off-by: Michael Kelley <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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hv_netvsc: Use VF's tso_max_size value when data path is VF

On Azure, increasing VF's gso/gro packet size to up-to GSO_MAX_SIZE
is not possible without allowing the same for netvsc NIC
(as the NICs

hv_netvsc: Use VF's tso_max_size value when data path is VF

On Azure, increasing VF's gso/gro packet size to up-to GSO_MAX_SIZE
is not possible without allowing the same for netvsc NIC
(as the NICs are bonded together). For bonded NICs, the min of the max
aggregated pkt size of the members is propagated in the stack.

Therefore, we use netif_set_tso_max_size() to set max aggregated pkt size
to VF's packet size for netvsc too, when the data path is switched over
to the VF
Tested on azure env with Accelerated Networking enabled and disabled.

Signed-off-by: Shradha Gupta <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Replace one-element array with flexible array member

Replace the deprecated one-element array with a modern flexible array
member in the struct nvsp_1_message_send_receive_buffer_complete

hv_netvsc: Replace one-element array with flexible array member

Replace the deprecated one-element array with a modern flexible array
member in the struct nvsp_1_message_send_receive_buffer_complete.

Use struct_size_t(,,1) instead of sizeof() to maintain the same size.

Compile-tested only.

Link: https://github.com/KSPP/linux/issues/79
Signed-off-by: Thorsten Blum <[email protected]>
Tested-by: Roman Kisel <[email protected]>
Reviewed-by: Roman Kisel <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: netvsc: Update default VMBus channels

Change VMBus channels macro (VRSS_CHANNEL_DEFAULT) in
Linux netvsc from 8 to 16 to align with Azure Windows VM
and improve networking throughput.

For VMs

net: netvsc: Update default VMBus channels

Change VMBus channels macro (VRSS_CHANNEL_DEFAULT) in
Linux netvsc from 8 to 16 to align with Azure Windows VM
and improve networking throughput.

For VMs having less than 16 vCPUS, the channels depend
on number of vCPUs. For greater than 16 vCPUs,
set the channels to maximum of VRSS_CHANNEL_DEFAULT and
number of physical cores / 2 which is returned by
netif_get_num_default_rss_queues() as a way to optimize CPU
resource utilization and scale for high-end processors with
many cores.
Maximum number of channels are by default set to 64.

Based on this change the channel creation would change as follows:

-----------------------------------------------------------------
| No. of vCPU | dev_info->num_chn | channels created |
-----------------------------------------------------------------
| 1-16 | 16 | vCPU |
| >16 | max(16,#cores/2) | min(64 , max(16,#cores/2)) |
-----------------------------------------------------------------

Performance tests showed significant improvement in throughput:
- 0.54% for 16 vCPUs
- 0.83% for 32 vCPUs
- 0.86% for 48 vCPUs
- 9.72% for 64 vCPUs
- 13.57% for 96 vCPUs

Signed-off-by: Erni Sri Satya Vennela <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Reviewed-by: Shradha Gupta <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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eth: add missing xdp.h includes in drivers

Handful of drivers currently expect to get xdp.h by virtue
of including netdevice.h. This will soon no longer be the case
so add explicit includes.

Review

eth: add missing xdp.h includes in drivers

Handful of drivers currently expect to get xdp.h by virtue
of including netdevice.h. This will soon no longer be the case
so add explicit includes.

Reviewed-by: Wei Fang <[email protected]>
Reviewed-by: Gerhard Engleder <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>

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hv_netvsc: Allocate rx indirection table size dynamically

Allocate the size of rx indirection table dynamically in netvsc
from the value of size provided by OID_GEN_RECEIVE_SCALE_CAPABILITIES
query

hv_netvsc: Allocate rx indirection table size dynamically

Allocate the size of rx indirection table dynamically in netvsc
from the value of size provided by OID_GEN_RECEIVE_SCALE_CAPABILITIES
query instead of using a constant value of ITAB_NUM.

Signed-off-by: Shradha Gupta <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Tested-on: Ubuntu22 (azure VM, SKU size: Standard_F72s_v2)
Testcases:
1. ethtool -x eth0 output
2. LISA testcase:PERF-NETWORK-TCP-THROUGHPUT-MULTICONNECTION-NTTTCP-Synthetic
3. LISA testcase:PERF-NETWORK-TCP-THROUGHPUT-MULTICONNECTION-NTTTCP-SRIOV
Reviewed-by: Simon Horman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Remove second mapping of send and recv buffers

With changes to how Hyper-V guest VMs flip memory between private
(encrypted) and shared (decrypted), creating a second kernel virtual
mappi

hv_netvsc: Remove second mapping of send and recv buffers

With changes to how Hyper-V guest VMs flip memory between private
(encrypted) and shared (decrypted), creating a second kernel virtual
mapping for shared memory is no longer necessary. Everything needed
for the transition to shared is handled by set_memory_decrypted().

As such, remove the code to create and manage the second
mapping for the pre-allocated send and recv buffers. This mapping
is the last user of hv_map_memory()/hv_unmap_memory(), so delete
these functions as well. Finally, hv_map_memory() is the last
user of vmap_pfn() in Hyper-V guest code, so remove the Kconfig
selection of VMAP_PFN.

Signed-off-by: Michael Kelley <[email protected]>
Reviewed-by: Tianyu Lan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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hv_netvsc: Fix race between VF offering and VF association message from host

During vm boot, there might be possibility that vf registration
call comes before the vf association from host to vm.

An

hv_netvsc: Fix race between VF offering and VF association message from host

During vm boot, there might be possibility that vf registration
call comes before the vf association from host to vm.

And this might break netvsc vf path, To prevent the same block
vf registration until vf bind message comes from host.

Cc: [email protected]
Fixes: 00d7ddba11436 ("hv_netvsc: pair VF based on serial number")
Reviewed-by: Haiyang Zhang <[email protected]>
Signed-off-by: Gaurav Kohli <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Add support for XDP_REDIRECT

Handle XDP_REDIRECT action in netvsc driver.
Also, transparently pass ndo_xdp_xmit to VF when available.

Signed-off-by: Haiyang Zhang <[email protected]

hv_netvsc: Add support for XDP_REDIRECT

Handle XDP_REDIRECT action in netvsc driver.
Also, transparently pass ndo_xdp_xmit to VF when available.

Signed-off-by: Haiyang Zhang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: netvsc: Add Isolation VM support for netvsc driver

In Isolation VM, all shared memory with host needs to mark visible
to host via hvcall. vmbus_establish_gpadl() has already done it for
netvsc

net: netvsc: Add Isolation VM support for netvsc driver

In Isolation VM, all shared memory with host needs to mark visible
to host via hvcall. vmbus_establish_gpadl() has already done it for
netvsc rx/tx ring buffer. The page buffer used by vmbus_sendpacket_
pagebuffer() stills need to be handled. Use DMA API to map/umap
these memory during sending/receiving packet and Hyper-V swiotlb
bounce buffer dma address will be returned. The swiotlb bounce buffer
has been masked to be visible to host during boot up.

rx/tx ring buffer is allocated via vzalloc() and they need to be
mapped into unencrypted address space(above vTOM) before sharing
with host and accessing. Add hv_map/unmap_memory() to map/umap rx
/tx ring buffer.

Signed-off-by: Tianyu Lan <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM

Mark vmbus ring buffer visible with set_memory_decrypted() when
establish gpadl handle.

Reviewed-by: Michael Kelley <mikel

Drivers: hv: vmbus: Mark vmbus ring buffer visible to host in Isolation VM

Mark vmbus ring buffer visible with set_memory_decrypted() when
establish gpadl handle.

Reviewed-by: Michael Kelley <[email protected]>
Signed-off-by: Tianyu Lan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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hv_netvsc: Avoid field-overflowing memcpy()

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally wr

hv_netvsc: Avoid field-overflowing memcpy()

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Add flexible array to represent start of buf_info, improving readability
and avoid future warning where memcpy() thinks it is writing past the
end of the structure.

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer

Pointers to ring-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values o

Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer

Pointers to ring-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values or modify
packet fields after they are processed by the guest. To defend
against these scenarios, return a copy of the incoming VMBus packet
after validating its length and offset fields in hv_pkt_iter_first().
In this way, the packet can no longer be modified by the host.

Signed-off-by: Andres Beltran <[email protected]>
Co-developed-by: Andrea Parri (Microsoft) <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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hv_netvsc: Add error handling while switching data path

Add error handling in case of failure to send switching data path message
to the host.

Reported-by: Shachar Raindel <[email protected]>

hv_netvsc: Add error handling while switching data path

Add error handling in case of failure to send switching data path message
to the host.

Reported-by: Shachar Raindel <[email protected]>
Signed-off-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Fix validation in netvsc_linkstatus_callback()

Contrary to the RNDIS protocol specification, certain (pre-Fe)
implementations of Hyper-V's vSwitch did not account for the status
buffer fi

hv_netvsc: Fix validation in netvsc_linkstatus_callback()

Contrary to the RNDIS protocol specification, certain (pre-Fe)
implementations of Hyper-V's vSwitch did not account for the status
buffer field in the length of an RNDIS packet; the bug was fixed in
newer implementations. Validate the status buffer fields using the
length of the 'vmtransfer_page' packet (all implementations), that
is known/validated to be less than or equal to the receive section
size and not smaller than the length of the RNDIS message.

Reported-by: Dexuan Cui <[email protected]>
Suggested-by: Haiyang Zhang <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Fixes: 505e3f00c3f36 ("hv_netvsc: Add (more) validation for untrusted Hyper-V values")
Signed-off-by: David S. Miller <[email protected]>

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Revert "Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer"

This reverts commit a8c3209998afb5c4941b49e35b513cea9050cb4a.

It is reported that the said commit caused regression

Revert "Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer"

This reverts commit a8c3209998afb5c4941b49e35b513cea9050cb4a.

It is reported that the said commit caused regression in netvsc.

Reported-by: Andrea Parri (Microsoft) <[email protected]>
Signed-off-by: Wei Liu <[email protected]>

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Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer

Pointers to ring-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values o

Drivers: hv: vmbus: Copy packets sent by Hyper-V out of the ring buffer

Pointers to ring-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values or modify
packet fields after they are processed by the guest. To defend
against these scenarios, return a copy of the incoming VMBus packet
after validating its length and offset fields in hv_pkt_iter_first().
In this way, the packet can no longer be modified by the host.

Signed-off-by: Andres Beltran <[email protected]>
Co-developed-by: Andrea Parri (Microsoft) <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Michael Kelley <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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hv_netvsc: Copy packets sent by Hyper-V out of the receive buffer

Pointers to receive-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values or

hv_netvsc: Copy packets sent by Hyper-V out of the receive buffer

Pointers to receive-buffer packets sent by Hyper-V are used within the
guest VM. Hyper-V can send packets with erroneous values or modify
packet fields after they are processed by the guest. To defend against
these scenarios, copy (sections of) the incoming packet after validating
their length and offset fields in netvsc_filter_receive(). In this way,
the packet can no longer be modified by the host.

Reported-by: Juan Vazquez <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening

Currently, pointers to guest memory are passed to Hyper-V as
transaction IDs in netvsc. In the face of errors or malici

hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening

Currently, pointers to guest memory are passed to Hyper-V as
transaction IDs in netvsc. In the face of errors or malicious
behavior in Hyper-V, netvsc should not expose or trust the transaction
IDs returned by Hyper-V to be valid guest memory addresses. Instead,
use small integers generated by vmbus_requestor as requests
(transaction) IDs.

Signed-off-by: Andres Beltran <[email protected]>
Co-developed-by: Andrea Parri (Microsoft) <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Reviewed-by: Michael Kelley <[email protected]>
Acked-by: Jakub Kicinski <[email protected]>
Reviewed-by: Wei Liu <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Wei Liu <[email protected]>

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hv_netvsc: Add validation for untrusted Hyper-V values

For additional robustness in the face of Hyper-V errors or malicious
behavior, validate all values that originate from packets that Hyper-V
has

hv_netvsc: Add validation for untrusted Hyper-V values

For additional robustness in the face of Hyper-V errors or malicious
behavior, validate all values that originate from packets that Hyper-V
has sent to the guest in the host-to-guest ring buffer. Ensure that
invalid values cannot cause indexing off the end of an array, or
subvert an existing validation via integer overflow. Ensure that
outgoing packets do not have any leftover guest memory that has not
been zeroed out.

Signed-off-by: Andres Beltran <[email protected]>
Co-developed-by: Andrea Parri (Microsoft) <[email protected]>
Signed-off-by: Andrea Parri (Microsoft) <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: [email protected]
Reviewed-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Cache the current data path to avoid duplicate call and message

The previous change "hv_netvsc: Switch the data path at the right time
during hibernation" adds the call of netvsc_vf_chang

hv_netvsc: Cache the current data path to avoid duplicate call and message

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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: add support for vlans in AF_PACKET mode

Vlan tagged packets are getting dropped when used with DPDK that uses
the AF_PACKET interface on a hyperV guest.

The packet layer uses the tpacket

hv_netvsc: add support for vlans in AF_PACKET mode

Vlan tagged packets are getting dropped when used with DPDK that uses
the AF_PACKET interface on a hyperV guest.

The packet layer uses the tpacket interface to communicate the vlans
information to the upper layers. On Rx path, these drivers can read the
vlan info from the tpacket header but on the Tx path, this information
is still within the packet frame and requires the paravirtual drivers to
push this back into the NDIS header which is then used by the host OS to
form the packet.

This transition from the packet frame to NDIS header is currently missing
hence causing the host OS to drop the all vlan tagged packets sent by
the drivers that use AF_PACKET (ETH_P_ALL) such as DPDK.

Here is an overview of the changes in the vlan header in the packet path:

The RX path (userspace handles everything):
1. RX VLAN packet is stripped by HOST OS and placed in NDIS header
2. Guest Kernel RX hv_netvsc packets and moves VLAN info from NDIS
header into kernel SKB
3. Kernel shares packets with user space application with PACKET_MMAP.
The SKB VLAN info is copied to tpacket layer and indication set
TP_STATUS_VLAN_VALID.
4. The user space application will re-insert the VLAN info into the frame

The TX path:
1. The user space application has the VLAN info in the frame.
2. Guest kernel gets packets from the application with PACKET_MMAP.
3. The kernel later sends the frame to the hv_netvsc driver. The only way
to send VLANs is when the SKB is setup & the VLAN is stripped from the
frame.
4. TX VLAN is re-inserted by HOST OS based on the NDIS header. If it sees
a VLAN in the frame the packet is dropped.

Cc: [email protected]
Cc: Sriram Krishnan <[email protected]>
Signed-off-by: Sriram Krishnan <[email protected]>
Reviewed-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Add XDP support

This patch adds support of XDP in native mode for hv_netvsc driver, and
transparently sets the XDP program on the associated VF NIC as well.

Setting / unsetting XDP progr

hv_netvsc: Add XDP support

This patch adds support of XDP in native mode for hv_netvsc driver, and
transparently sets the XDP program on the associated VF NIC as well.

Setting / unsetting XDP program on synthetic NIC (netvsc) propagates to
VF NIC automatically. Setting / unsetting XDP program on VF NIC directly
is not recommended, also not propagated to synthetic NIC, and may be
overwritten by setting of synthetic NIC.

The Azure/Hyper-V synthetic NIC receive buffer doesn't provide headroom
for XDP. We thought about re-use the RNDIS header space, but it's too
small. So we decided to copy the packets to a page buffer for XDP. And,
most of our VMs on Azure have Accelerated Network (SRIOV) enabled, so
most of the packets run on VF NIC. The synthetic NIC is considered as a
fallback data-path. So the data copy on netvsc won't impact performance
significantly.

XDP program cannot run with LRO (RSC) enabled, so you need to disable LRO
before running XDP:
ethtool -K eth0 lro off

XDP actions not yet supported:
XDP_REDIRECT

Signed-off-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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hv_netvsc: Fix unwanted rx_table reset

In existing code, the receive indirection table, rx_table, is in
struct rndis_device, which will be reset when changing MTU, ringparam,
etc. User configured re

hv_netvsc: Fix unwanted rx_table reset

In existing code, the receive indirection table, rx_table, is in
struct rndis_device, which will be reset when changing MTU, ringparam,
etc. User configured receive indirection table values will be lost.

To fix this, move rx_table to struct net_device_context, and check
netif_is_rxfh_configured(), so rx_table will be set to default only
if no user configured value.

Fixes: ff4a44199012 ("netvsc: allow get/set of RSS indirection table")
Signed-off-by: Haiyang Zhang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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