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[ Upstream commit 527db74b71ee5a279f818aae51f2c26b4e5c7648 ]
Atomic operations on the NFP are currently always in big endian.
The driver keeps track of regions of memory storing atomic values
and byte swaps them accordingly. There are corner cases where
the map values may be initialized before the driver knows they
are used as atomic counters. This can happen either when the
datapath is performing the update and the stack contents are
unknown or when map is updated before the program which will
use it for atomic values is loaded.
To avoid situation where user initializes the value to 0 1 2 3
and then after loading a program which uses the word as an atomic
counter starts reading 3 2 1 0 - only allow atomic counters to be
initialized to endian-neutral values.
For updates from the datapath the stack information may not be
as precise, so just allow initializing such values to 0.
Example code which would break:
struct bpf_map_def SEC("maps") rxcnt = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(__u32),
.value_size = sizeof(__u64),
.max_entries = 1,
};
int xdp_prog1()
{
__u64 nonzeroval = 3;
__u32 key = 0;
__u64 *value;
value = bpf_map_lookup_elem(&rxcnt, &key);
if (!value)
bpf_map_update_elem(&rxcnt, &key, &nonzeroval, BPF_ANY);
else
__sync_fetch_and_add(value, 1);
return XDP_PASS;
}
$ offload bpftool map dump
key: 00 00 00 00 value: 00 00 00 03 00 00 00 00
should be:
$ offload bpftool map dump
key: 00 00 00 00 value: 03 00 00 00 00 00 00 00
Reported-by: David Beckett <david.beckett@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Add support for adjust_tail. There are no FW changes needed but add
a FW capability just in case there would be any issue with previously
released FW, or we will have to change the ABI in the future.
The helper is trivial and shouldn't be used too often so just inline
the body of the function. We add the delta to locally maintained
packet length register and check for overflow, since add of negative
value must overflow if result is positive. Note that if delta of 0
would be allowed in the kernel this trick stops working and we need
one more instruction to compare lengths before and after the change.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Record perf maps by map ID, not raw kernel pointer. This helps
with debug messages, because printing pointers to logs is frowned
upon, and makes debug easier for the users, as map ID is something
they should be more familiar with. Note that perf maps are offload
neutral, therefore IDs won't be orphaned.
While at it use a rate limited print helper for the error message.
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Control queue is fairly low latency, and requires SKB allocations,
which means we can't even reach 0.5Msps with perf events. Allow
perf events to be delivered to data queues. This allows us to not
only use multiple queues, but also receive and deliver to user space
more than 5Msps per queue (Xeon E5-2630 v4 2.20GHz, no retpolines).
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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In preparation for SKB-less perf event handling make
nfp_bpf_event_output() take buffer address and length,
not SKB as parameters.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Create a higher-level entity to represent a device/ASIC to allow
programs and maps to be shared between device ports. The extra
work is required to make sure we don't destroy BPF objects as
soon as the netdev for which they were loaded gets destroyed,
as other ports may still be using them. When netdev goes away
all of its BPF objects will be moved to other netdevs of the
device, and only destroyed when last netdev is unregistered.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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NFP doesn't have integer divide instruction, this patch use reciprocal
algorithm (the basic one, reciprocal_div) to emulate it.
For each u32 divide, we would need 11 instructions to finish the operation.
7 (for multiplication) + 4 (various ALUs) = 11
Given NFP only supports multiplication no bigger than u32, we'd require
divisor and dividend no bigger than that as well.
Also eBPF doesn't support signed divide and has enforced this on C language
level by failing compilation. However LLVM assembler hasn't enforced this,
so it is possible for negative constant to leak in as a BPF_K operand
through assembly code, we reject such cases as well.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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NFP supports u16 and u32 multiplication. Multiplication is done 8-bits per
step, therefore we need 2 steps for u16 and 4 steps for u32.
We also need one start instruction to initialize the sequence and one or
two instructions to fetch the result depending on either you need the high
halve of u32 multiplication.
For ALU64, if either operand is beyond u32's value range, we reject it. One
thing to note, if the source operand is BPF_K, then we need to check "imm"
field directly, and we'd reject it if it is negative. Because for ALU64,
"imm" (with s32 type) is expected to be sign extended to s64 which NFP mul
doesn't support. For ALU32, it is fine for "imm" be negative though,
because the result is 32-bits and here is no difference on the low halve
of result for signed/unsigned mul, so we will get correct result.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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NFP verifier hook is coping range information of the shift amount for
indirect shift operation so optimized shift sequences could be generated.
We want to use range info to do more things. For example, to decide whether
multiplication and divide are supported on the given range.
This patch simply let NFP verifier hook to copy range info for all operands
of all ALU operands.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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The two fields are a copy of umin and umax info of bpf_insn->src_reg
generated by verifier.
Rename to make their meaning clear.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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For indirect shifts, shift amount is not specified as constant, NFP needs
to get the shift amount through the low 5 bits of source A operand in
PREV_ALU, therefore extra instructions are needed compared with shifts by
constants.
Because NFP is 32-bit, so we are using register pair for 64-bit shifts and
therefore would need different instruction sequences depending on whether
shift amount is less than 32 or not.
NFP branch-on-bit-test instruction emitter is added by this patch and is
used for efficient runtime check on shift amount. We'd think the shift
amount is less than 32 if bit 5 is clear and greater or equal than 32
otherwise. Shift amount is greater than or equal to 64 will result in
undefined behavior.
This patch also use range info to avoid generating unnecessary runtime code
if we are certain shift amount is less than 32 or not.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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BPF has access to all internal FW datapath structures. Including
the structure containing RX queue selection. With little coordination
with the datapath we can let the offloaded BPF select the RX queue.
We just need a way to tell the datapath that queue selection has already
been done and it shouldn't overwrite it. Define a bit to tell datapath
BPF already selected a queue (QSEL_SET), if the selected queue is not
enabled (>= number of enabled queues) datapath will perform normal RSS.
BPF queue selection on the NIC can be used to replace standard
datapath RSS with fully programmable BPF/XDP RSS.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Add support for the perf_event_output family of helpers.
The implementation on the NFP will not match the host code exactly.
The state of the host map and rings is unknown to the device, hence
device can't return errors when rings are not installed. The device
simply packs the data into a firmware notification message and sends
it over to the host, returning success to the program.
There is no notion of a host CPU on the device when packets are being
processed. Device will only offload programs which set BPF_F_CURRENT_CPU.
Still, if map index doesn't match CPU no error will be returned (see
above).
Dropped/lost firmware notification messages will not cause "lost
events" event on the perf ring, they are only visible via device
error counters.
Firmware notification messages may also get reordered in respect
to the packets which caused their generation.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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For asynchronous events originating from the device, like perf event
output, we need to be able to make sure that objects being referred
to by the FW message are valid on the host. FW events can get queued
and reordered. Even if we had a FW message "barrier" we should still
protect ourselves from bogus FW output.
Add a reverse-mapping hash table and record in it all raw map pointers
FW may refer to. Only record neutral maps, i.e. perf event arrays.
These are currently the only objects FW can refer to. Use RCU protection
on the read side, update side is under RTNL.
Since program vs map destruction order is slightly painful for offload
simply take an extra reference on all the recorded maps to make sure
they don't disappear.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Comparison instruction requires a subtraction. If the constant
is negative we are more likely to fit it into a NFP instruction
directly if we change the sign and use addition.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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NFP has a prng register, which we can read to obtain a u32 worth
of pseudo random data. Generate code for it.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Allow atomic add to be used even when the value is not guaranteed
to fit into a 16 bit immediate. This requires the value to be pulled
as data, and therefore use of a transfer register and a context swap.
Track the information about possible lengths of the value, if it's
guaranteed to be larger than 16bits don't generate the code for the
optimized case at all.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Implement atomic add operation for 32 and 64 bit values. Depend
on the verifier to ensure alignment. Values have to be kept in
big endian and swapped upon read/write. For now only support
atomic add of a constant.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Support calling map_delete_elem() FW helper from the datapath
programs. For JIT checks and code are basically equivalent
to map lookups. Similarly to other map helper key must be on
the stack. Different pointer types are left for future extension.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Support calling map_update_elem() from the datapath programs
by calling into FW-provided helper. Value pointer is passed
in LM pointer #2. Keeping track of old state for arg3 is not
necessary, since LM pointer #2 will be always loaded in this
case, the trivial optimization for value at the bottom of the
stack can't be done here.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Our implementation has restriction on stack pointers for function
calls. Move the common checks into a helper for reuse. The state
has to be encapsulated into a structure to support parameters
other than BPF_REG_2.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch is the front end of this optimisation, it detects and marks
those packet reads that could be cached. Then the optimisation "backend"
will be activated automatically.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch assumes there is a packet data cache, and would try to read
packet data from the cache instead of from memory.
This patch only implements the optimisation "backend", it doesn't build
the packet data cache, so this optimisation is not enabled.
This patch has only enabled aligned packet data read, i.e. when the read
offset to the start of cache is REG_WIDTH aligned.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Commit 84ce5b987783 ("scripts: kernel-doc: improve nested logic to
handle multiple identifiers") improved the handling of nested structure
definitions in scripts/kernel-doc, and changed the expected format of
documentation. This causes new warnings to appear on W=1 builds.
Only comment changes.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Use the recently added extack support for eBPF offload in the driver.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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If an eBPF instruction is unknown to the driver JIT compiler, we can
reject the program at verification time.
Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Plug in to the stack's map offload callbacks for BPF map offload.
Get next call needs some special handling on the FW side, since
we can't send a NULL pointer to the FW there is a get first entry
FW command.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Verify our current constraints on the location of the key are
met and generate the code for calling map lookup on the datapath.
New relocation types have to be added - for helpers and return
addresses.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Parse helper function and supported map FW TLV capabilities.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Implement calls for FW map communication.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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For map support we will need to send and receive control messages.
Add basic support for sending a message to FW, and waiting for a
reply.
Control messages are tagged with a 16 bit ID. Add a simple ID
allocator and make sure we don't allow too many messages in flight,
to avoid request <> reply mismatches.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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To be able to split code into reasonable chunks we need to add
the map data structures already. Later patches will add code
piece by piece.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Instead of having an app callback per message type hand off
all offload-related handling to apps with one "rest of ndo_bpf"
callback.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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To make absolute relocated branches (branches which will be completely
rewritten with br_set_offset()) distinguishable in user space dumps
from normal jumps add a large offset to them.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Don't translate the program assuming it will be loaded at a given
address. This will be required for sharing programs between ports
of the same NIC, tail calls and subprograms. It will also make the
jump targets easier to understand when dumping the program to user
space.
Translate the program as if it was going to be loaded at address
zero. When load happens add the load offset in and set addresses
of special branches.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Jump target resolution should be in jit.c not offload.c.
No functional changes.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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To allow verifier instruction callbacks without any extra locking
NETDEV_UNREGISTER notification would wait on a waitqueue for verifier
to finish. This design decision was made when rtnl lock was providing
all the locking. Use the read/write lock instead and remove the
workqueue.
Verifier will now call into the offload code, so dev_ops are moved
to offload structure. Since verifier calls are all under
bpf_prog_is_dev_bound() we no longer need static inline implementations
to please builds with CONFIG_NET=n.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Lots of overlapping changes. Also on the net-next side
the XDP state management is handled more in the generic
layers so undo the 'net' nfp fix which isn't applicable
in net-next.
Include a necessary change by Jakub Kicinski, with log message:
====================
cls_bpf no longer takes care of offload tracking. Make sure
netdevsim performs necessary checks. This fixes a warning
caused by TC trying to remove a filter it has not added.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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After TC offloads were converted to callbacks we have no choice
but keep track of the offloaded filter in the driver.
The check for nn->dp.bpf_offload_xdp was a stop gap solution
to make sure failed TC offload won't disable XDP, it's no longer
necessary. nfp_net_bpf_offload() will return -EBUSY on
TC vs XDP conflicts.
Fixes: 3f7889c4c79b ("net: sched: cls_bpf: call block callbacks for offload")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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If the program is simple and has only one adjust head call
with constant parameters, we can check that the call will
always succeed at translation time. We need to track the
location of the call and make sure parameters are always
the same. We also have to check the parameters against
datapath constraints and ETH_HLEN.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Support bpf_xdp_adjust_head(). We need to check whether the
packet offset after adjustment is within datapath's limits.
We also check if the frame is at least ETH_HLEN long (similar
to the kernel implementation).
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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BPF FW creates a run time symbol called bpf_capabilities which
contains TLV-formatted capability information. Allocate app
private structure to store parsed capabilities and add a skeleton
of parsing logic.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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For NFP, we want to re-group a sequence of load/store pairs lowered from
memcpy/memmove into single memory bulk operation which then could be
accelerated using NFP CPP bus.
This patch extends the existing load/store auxiliary information by adding
two new fields:
struct bpf_insn *paired_st;
s16 ldst_gather_len;
Both fields are supposed to be carried by the the load instruction at the
head of the sequence. "paired_st" is the corresponding store instruction at
the head and "ldst_gather_len" is the gathered length.
If "ldst_gather_len" is negative, then the sequence is doing memory
load/store in descending order, otherwise it is in ascending order. We need
this information to detect overlapped memory access.
This patch then optimize memory bulk copy when the copy length is within
32-bytes.
The strategy of read/write used is:
* Read.
Use read32 (direct_ref), always.
* Write.
- length <= 8-bytes
write8 (direct_ref).
- length <= 32-bytes and is 4-byte aligned
write32 (direct_ref).
- length <= 32-bytes but is not 4-byte aligned
write8 (indirect_ref).
NOTE: the optimization should not change program semantics. The destination
register of the last load instruction should contain the same value before
and after this optimization.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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It is usual that we need to check if one BPF insn is for loading/storeing
data from/to memory.
Therefore, it makes sense to factor out related code to become common
helper functions.
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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NFP eBPF offload JIT engine is doing some instruction combine based
optimizations which however must not be safe if the combined sequences
are across basic block boarders.
Currently, there are post checks during fixing jump destinations. If the
jump destination is found to be eBPF insn that has been combined into
another one, then JIT engine will raise error and abort.
This is not optimal. The JIT engine ought to disable the optimization on
such cross-bb-border sequences instead of abort.
As there is no control flow information in eBPF infrastructure that we
can't do basic block based optimizations, this patch extends the existing
jump destination record pass to also flag the jump destination, then in
instruction combine passes we could skip the optimizations if insns in the
sequence are jump targets.
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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eBPF insns are internally organized as dual-list inside NFP offload JIT.
Random access to an insn needs to be done by either forward or backward
traversal along the list.
One place we need to do such traversal is at nfp_fixup_branches where one
traversal is needed for each jump insn to find the destination. Such
traversals could be avoided if jump destinations are collected through a
single travesal in a pre-scan pass, and such information could also be
useful in other places where jump destination info are needed.
This patch adds such jump destination collection in nfp_prog_prepare.
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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This patch adds support for backward jump on NFP.
- restrictions on backward jump in various functions have been removed.
- nfp_fixup_branches now supports backward jump.
There is one thing to note, currently an input eBPF JMP insn may generate
several NFP insns, for example,
NFP imm move insn A \
NFP compare insn B --> 3 NFP insn jited from eBPF JMP insn M
NFP branch insn C /
---
NFP insn X --> 1 NFP insn jited from eBPF insn N
---
...
therefore, we are doing sanity check to make sure the last jited insn from
an eBPF JMP is a NFP branch instruction.
Once backward jump is allowed, it is possible an eBPF JMP insn is at the
end of the program. This is however causing trouble for the sanity check.
Because the sanity check requires the end index of the NFP insns jited from
one eBPF insn while only the start index is recorded before this patch that
we can only get the end index by:
start_index_of_the_next_eBPF_insn - 1
or for the above example:
start_index_of_eBPF_insn_N (which is the index of NFP insn X) - 1
nfp_fixup_branches was using nfp_for_each_insn_walk2 to expose *next* insn
to each iteration during the traversal so the last index could be
calculated from which. Now, it needs some extra code to handle the last
insn. Meanwhile, the use of walk2 is actually unnecessary, we could simply
use generic single instruction walk to do this, the next insn could be
easily calculated using list_next_entry.
So, this patch migrates the jump fixup traversal method to
*list_for_each_entry*, this simplifies the code logic a little bit.
The other thing to note is a new state variable "last_bpf_off" is
introduced to track the index of the last jited NFP insn. This is necessary
because NFP is generating special purposes epilogue sequences, so the index
of the last jited NFP insn is *not* always nfp_prog->prog_len - 1.
Suggested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Following steps are taken in the driver to offload an XDP program:
XDP_SETUP_PROG:
* prepare:
- allocate program state;
- run verifier (bpf_analyzer());
- run translation;
* load:
- stop old program if needed;
- load program;
- enable BPF if not enabled;
* clean up:
- free program image.
With new infrastructure the flow will look like this:
BPF_OFFLOAD_VERIFIER_PREP:
- allocate program state;
BPF_OFFLOAD_TRANSLATE:
- run translation;
XDP_SETUP_PROG:
- stop old program if needed;
- load program;
- enable BPF if not enabled;
BPF_OFFLOAD_DESTROY:
- free program image.
Take advantage of the new infrastructure. Allocation of driver
metadata has to be moved from jit.c to offload.c since it's now
done at a different stage. Since there is no separate driver
private data for verification step, move temporary nfp_meta
pointer into nfp_prog. We will now use user space context
offsets.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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struct nfp_prog is currently only used internally by the translator.
This means there is a lot of parameter passing going on, between
the translator and different stages of offload. Simplify things
by allocating nfp_prog in offload.c already.
We will now use kmalloc() to allocate the program area and only
DMA map it for the time of loading (instead of allocating DMA
coherent memory upfront).
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Most of offload/translation prepare logic will be moved to
offload.c. To help git generate more reasonable diffs
move nfp_prog_prepare() and nfp_prog_free() functions
there as a first step.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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