Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

branches: 1.2.2;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.1.2;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Merge thorpej-cfargs2.

branches: 1.2.8;
Merge thorpej-cfargs branch:

Simplify and make extensible the config_search() / config_found() /
config_attach() interfaces: rather than having different variants for
which arguments you want pass along, just have a single call that
takes a variadic list of tag-value arguments.

Adjust all call sites:
- Simplify wherever possible; don't pass along arguments that aren't
actually needed.
- Don't be explicit about what interface attribute is attaching if
the device only has one. (More simplification.)
- Add a config_probe() function to be used in indirect configuiration
situations, making is visibly easier to see when indirect config is
in play, and allowing for future change in semantics. (As of now,
this is just a wrapper around config_match(), but that is an
implementation detail.)

Remove unnecessary or redundant interface attributes where they're not
needed.

There are currently 5 "cfargs" defined:
- CFARG_SUBMATCH (submatch function for direct config)
- CFARG_SEARCH (search function for indirect config)
- CFARG_IATTR (interface attribte)
- CFARG_LOCATORS (locators array)
- CFARG_DEVHANDLE (devhandle_t - wraps OFW, ACPI, etc. handles)

...and a sentinel value CFARG_EOL.

Add some extra sanity checking to ensure that interface attributes
aren't ambiguous.

Use CFARG_DEVHANDLE in MI FDT, OFW, and ACPI code, and macppc and shark
ports to associate those device handles with device_t instance. This
will trickle trough to more places over time (need back-end for pre-OFW
Sun OBP; any others?).

branches: 1.1.2; 1.1.4; 1.1.16;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.1.2; 1.1.4;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.2.2; 1.2.6;
Update Hyper-V related drivers description.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Merge thorpej-cfargs2.

branches: 1.8.8;
Merge thorpej-cfargs branch:

Simplify and make extensible the config_search() / config_found() /
config_attach() interfaces: rather than having different variants for
which arguments you want pass along, just have a single call that
takes a variadic list of tag-value arguments.

Adjust all call sites:
- Simplify wherever possible; don't pass along arguments that aren't
actually needed.
- Don't be explicit about what interface attribute is attaching if
the device only has one. (More simplification.)
- Add a config_probe() function to be used in indirect configuiration
situations, making is visibly easier to see when indirect config is
in play, and allowing for future change in semantics. (As of now,
this is just a wrapper around config_match(), but that is an
implementation detail.)

Remove unnecessary or redundant interface attributes where they're not
needed.

There are currently 5 "cfargs" defined:
- CFARG_SUBMATCH (submatch function for direct config)
- CFARG_SEARCH (search function for indirect config)
- CFARG_IATTR (interface attribte)
- CFARG_LOCATORS (locators array)
- CFARG_DEVHANDLE (devhandle_t - wraps OFW, ACPI, etc. handles)

...and a sentinel value CFARG_EOL.

Add some extra sanity checking to ensure that interface attributes
aren't ambiguous.

Use CFARG_DEVHANDLE in MI FDT, OFW, and ACPI code, and macppc and shark
ports to associate those device handles with device_t instance. This
will trickle trough to more places over time (need back-end for pre-OFW
Sun OBP; any others?).

branches: 1.7.2;
hvkbd(4): Don't wait forever.

branches: 1.6.8;
hvn(4), hvkbd(4): Only need to poll when cold.

vmbus(4), hvn(4), hvkbd(4): Fixed wait time for tsleep(9).

hvn(4), hvkbd(4): No need to call vmbus_channel_setdeferred().

These devices do not perform batch reading.

in many device attach paths, allocate memory with KM_SLEEP instead of KM_NOSLEEP
and remove code to handle failures that can no longer happen.

branches: 1.2.2;
Fix build for !WSDISPLAY_COMPAT_RAWKBD.

branches: 1.1.2; 1.1.4;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.1.2; 1.1.4;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

Merge thorpej-cfargs2.

branches: 1.6.2;
hvs(4): Pass correct pointer of scsibus device to scsi_probe_bus().

branches: 1.5.2;
Merge thorpej-cfargs branch:

Simplify and make extensible the config_search() / config_found() /
config_attach() interfaces: rather than having different variants for
which arguments you want pass along, just have a single call that
takes a variadic list of tag-value arguments.

Adjust all call sites:
- Simplify wherever possible; don't pass along arguments that aren't
actually needed.
- Don't be explicit about what interface attribute is attaching if
the device only has one. (More simplification.)
- Add a config_probe() function to be used in indirect configuiration
situations, making is visibly easier to see when indirect config is
in play, and allowing for future change in semantics. (As of now,
this is just a wrapper around config_match(), but that is an
implementation detail.)

Remove unnecessary or redundant interface attributes where they're not
needed.

There are currently 5 "cfargs" defined:
- CFARG_SUBMATCH (submatch function for direct config)
- CFARG_SEARCH (search function for indirect config)
- CFARG_IATTR (interface attribte)
- CFARG_LOCATORS (locators array)
- CFARG_DEVHANDLE (devhandle_t - wraps OFW, ACPI, etc. handles)

...and a sentinel value CFARG_EOL.

Add some extra sanity checking to ensure that interface attributes
aren't ambiguous.

Use CFARG_DEVHANDLE in MI FDT, OFW, and ACPI code, and macppc and shark
ports to associate those device handles with device_t instance. This
will trickle trough to more places over time (need back-end for pre-OFW
Sun OBP; any others?).

branches: 1.4.4;
Use howmany() macro.

hvs(4), hvn(4): Set correct size for bus_dmamap_sync(9).

in many device attach paths, allocate memory with KM_SLEEP instead of KM_NOSLEEP
and remove code to handle failures that can no longer happen.

branches: 1.1.2; 1.1.6; 1.1.8;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

branches: 1.2.2; 1.2.6;
Update Hyper-V related drivers description.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

rename sneaky snyc in hvtimesnyc_sample_verbose variable to sync.

branches: 1.2.2; 1.2.6;
Update Hyper-V related drivers description.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

hvn(4) can be added and deleted dynamically.

Get a Hyper-V virtual processor id in cpu_hatch().

Currently, it is got in config_interrupts context.
However, since it is required when attaching a device,
it is got earlier than now.

Clear the allocated memory in hyperv_dma_alloc().

branches: 1.2.2;
Avoid undefined reference to `hyperv_is_gen1' without hyperv(4).

branches: 1.1.2;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

branches: 1.1.2; 1.1.6;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

hyper-v: move idt vector allocating to vmbus_init_interrupts_md()
for refactoring

And, the deallocating is also moved to
vmbus_deinit_interrupts_md().

reviewed by nonaka@n.o.

hvn(4) can be added and deleted dynamically.

Get a Hyper-V virtual processor id in cpu_hatch().

Currently, it is got in config_interrupts context.
However, since it is required when attaching a device,
it is got earlier than now.

branches: 1.2.2;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.1.2;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

copy dhost and shost without flagging overflow

avoid buffer overflow when copying the ether header host into the ether vland header host
on hyper-v

sys: Drop redundant NULL check before m_freem(9)

m_freem(9) safely has accepted NULL argument at least since 4.2BSD:
https://www.tuhs.org/cgi-bin/utree.pl?file=4.2BSD/usr/src/sys/sys/uipc_mbuf.c

Compile-tested on amd64/ALL.

Suggested by knakahara@

branches: 1.27.2;
fix spelling mistakes, mainly in comments and log messages.

Remove unnecssary #include

fix triple s typos in comments.

Eliminate use of IFF_OACTIVE.

Audit unload/unmap v.s. free against DMA buffer for sys/dev;
make sure that bus_dmamap_unload(9) [or bus_dmamap_destroy(9)] or
bus_dmamem_unmap(9) are preceding to freeing DMA buffer, if it is
loaded or mapped, respectively.

This is mandatory for some archs. See, e.g.:

http://www.nerv.org/netbsd/?q=id:20210511T013030Z.013443cc790088147e4beed43f53dedabeaf9312
http://www.nerv.org/netbsd/?q=id:20220511T172220Z.561179f0b6fcc5b9cd73e274f69d74e2ce9e4c93

For some drivers, resource leaks for error paths are fixed at
the same time.

XXX XXX XXX
Compile test only (at least one arch per driver).

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

if_attach and if_initialize cannot fail, don't test return value

These were originally made failable back in 2017 when if_initialize
allocated a softint in every interface for link state changes, so
that it could fail gracefully instead of panicking:

https://mail-index.NetBSD.org/source-changes/2017/10/23/msg089053.html

However, this spawned many seldom- or never-tested error branches,
which are risky to have around. And that softint in every interface
has since been replaced by a single global workqueue, because link
state changes require thread context but not low latency or high
throughput:

https://mail-index.NetBSD.org/source-changes/2020/02/06/msg113759.html

So there is no longer any reason for if_initialize to fail. (The
subroutine if_stats_init can't fail because percpu_alloc can't fail
either.)

There is a snag: the softint_establish in if_percpuq_create could
fail, potentially leading to bad consequences later on trying to use
the softint. This change doesn't introduce any new bugs because of
the snag -- if_percpuq_attach was already broken. However, the snag
can be better addressed without spawning error branches, either by
using a single softint or making softints less scarce.

(Separate commit will change the signatures of if_attach and
if_initialize to return void, scheduled to ride whatever is the next
convenient kernel bump.)

Patch and testing on amd64 and evbmips64-eb by maya@; commit message
soliloquy, and compile-testing on evbppc/i386/earmv7hf, by me.

branches: 1.20.4;
hvn(4): Don't wait forever.

hvn(4): fix unable to ifconfig up/down.

branches: 1.18.2;
hvn(4): Prevent from occur panic when acquiring the media status.

hvn(4) sleeps during hvn_media_status(), and thus requires an adaptive mutex
for the media lock. Taken from recent iwm(4) change.

Use ifmedia_fini().

Adopt <net/if_stats.h>.

branches: 1.15.2;
hvn(4): Handle CFI field of VLAN.

hvn(4): Use vlan_{get,set,has}_tag().

hvn(4) can be added and deleted dynamically.

hvn(4): Handle VMBUS_CHANPKT_TYPE_INBAND packet type.

hvn(4): Fix incorrect ident when waiting for NVS command response.

hvs(4), hvn(4): Set correct size for bus_dmamap_sync(9).

hvn(4), hvkbd(4): Only need to poll when cold.

vmbus(4), hvn(4), hvkbd(4): Fixed wait time for tsleep(9).

Fixed incorrect m_defrag return value check.

hvn(4), hvkbd(4): No need to call vmbus_channel_setdeferred().

These devices do not perform batch reading.

in many device attach paths, allocate memory with KM_SLEEP instead of KM_NOSLEEP
and remove code to handle failures that can no longer happen.

branches: 1.4.2;
Don't automatically set ec_capenable's ETHERCAP_VLAN_HWTAGGING bit in
vlan_config() to make it user-controllable. Instead, set the bit in
xxx_attach().

branches: 1.3.2;
Even if we don't use MII(4), use the common path of SIOC[GS]IFMEDIA in
sys/net/if_ethersubr.c if we can.
- Add ec_ifmedia into struct ethercom.
- ec_mii in struct ethercom is kept and used as it is. It might be used in
future. Note that some Ethernet drivers which _DOESN'T_ use mii(4) use
ec_mii for keeping the if_media. Those should be changed in future.

branches: 1.2.2;
Centralize ETHER_ALIGN into net/if_ether.h. Note that this commit also changes
if_upgt.c's ETHER_ALIGN from 0 to 2.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

fix spelling mistakes, mainly in comments and log messages.

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

fix various typos, mainly in comments, but also in man pages and log messages.

branches: 1.1.2; 1.1.6;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

hyperv(4): Use paravirt_membar_sync(9) where needed.

Annotate each remaining membar_sync with the bus_dmamap_sync that I
think it really ought to be. Sprinkle some more annotations of where
bus_dmamap_sync ought to go. (Although these likely don't matter --
except as __insn_barrier equivalents -- for hyperv on x86, and these
buffers are not likely to ever bounce, the syncs may be needed on Arm
for the underlying r-before-r/w and r/w-before-w ordering if nothing
else.)

PR kern/59618: occasional virtio block device lock ups/hangs

(hyperv(4) is not virtio(4) but the same fundamental issue arises.)

branches: 1.19.2;
vmbus(4): Fix missing conversion to condvar(9).

branches: 1.18.4; 1.18.10;
Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

sys: Use membar_release/acquire around reference drop.

This just goes through my recent reference count membar audit and
changes membar_exit to membar_release and membar_enter to
membar_acquire -- this should make everything cheaper on most CPUs
without hurting correctness, because membar_acquire is generally
cheaper than membar_enter.

sys: Membar audit around reference count releases.

If two threads are using an object that is freed when the reference
count goes to zero, we need to ensure that all memory operations
related to the object happen before freeing the object.

Using an atomic_dec_uint_nv(&refcnt) == 0 ensures that only one
thread takes responsibility for freeing, but it's not enough to
ensure that the other thread's memory operations happen before the
freeing.

Consider:

Thread A Thread B
obj->foo = 42; obj->baz = 73;
mumble(&obj->bar); grumble(&obj->quux);
/* membar_exit(); */ /* membar_exit(); */
atomic_dec -- not last atomic_dec -- last
/* membar_enter(); */
KASSERT(invariant(obj->foo,
obj->bar));
free_stuff(obj);

The memory barriers ensure that

obj->foo = 42;
mumble(&obj->bar);

in thread A happens before

KASSERT(invariant(obj->foo, obj->bar));
free_stuff(obj);

in thread B. Without them, this ordering is not guaranteed.

So in general it is necessary to do

membar_exit();
if (atomic_dec_uint_nv(&obj->refcnt) != 0)
return;
membar_enter();

to release a reference, for the `last one out hit the lights' style
of reference counting. (This is in contrast to the style where one
thread blocks new references and then waits under a lock for existing
ones to drain with a condvar -- no membar needed thanks to mutex(9).)

I searched for atomic_dec to find all these. Obviously we ought to
have a better abstraction for this because there's so much copypasta.
This is a stop-gap measure to fix actual bugs until we have that. It
would be nice if an abstraction could gracefully handle the different
styles of reference counting in use -- some years ago I drafted an
API for this, but making it cover everything got a little out of hand
(particularly with struct vnode::v_usecount) and I ended up setting
it aside to work on psref/localcount instead for better scalability.

I got bored of adding #ifdef __HAVE_ATOMIC_AS_MEMBAR everywhere, so I
only put it on things that look performance-critical on 5sec review.
We should really adopt membar_enter_preatomic/membar_exit_postatomic
or something (except they are applicable only to atomic r/m/w, not to
atomic_load/store_*, making the naming annoying) and get rid of all
the ifdefs.

hyper-v: move idt vector allocating to vmbus_init_interrupts_md()
for refactoring

And, the deallocating is also moved to
vmbus_deinit_interrupts_md().

reviewed by nonaka@n.o.

Merge thorpej-cfargs2.

branches: 1.13.8;
Merge thorpej-cfargs branch:

Simplify and make extensible the config_search() / config_found() /
config_attach() interfaces: rather than having different variants for
which arguments you want pass along, just have a single call that
takes a variadic list of tag-value arguments.

Adjust all call sites:
- Simplify wherever possible; don't pass along arguments that aren't
actually needed.
- Don't be explicit about what interface attribute is attaching if
the device only has one. (More simplification.)
- Add a config_probe() function to be used in indirect configuiration
situations, making is visibly easier to see when indirect config is
in play, and allowing for future change in semantics. (As of now,
this is just a wrapper around config_match(), but that is an
implementation detail.)

Remove unnecessary or redundant interface attributes where they're not
needed.

There are currently 5 "cfargs" defined:
- CFARG_SUBMATCH (submatch function for direct config)
- CFARG_SEARCH (search function for indirect config)
- CFARG_IATTR (interface attribte)
- CFARG_LOCATORS (locators array)
- CFARG_DEVHANDLE (devhandle_t - wraps OFW, ACPI, etc. handles)

...and a sentinel value CFARG_EOL.

Add some extra sanity checking to ensure that interface attributes
aren't ambiguous.

Use CFARG_DEVHANDLE in MI FDT, OFW, and ACPI code, and macppc and shark
ports to associate those device handles with device_t instance. This
will trickle trough to more places over time (need back-end for pre-OFW
Sun OBP; any others?).

branches: 1.12.2;
vmbus(4): Don't wait forever.

branches: 1.11.2;
vmbus(4): Do not call hyperv_dma_alloc() in interrupt context.

The channel offer and rescind process is performed on another context.

vmbus(4): Fixed incorrect use of vmbus_wait() in vmbus_channel_scan().

Found by kUBSan.

Use howmany() macro.

hvn(4) can be added and deleted dynamically.

Get a Hyper-V virtual processor id in cpu_hatch().

Currently, it is got in config_interrupts context.
However, since it is required when attaching a device,
it is got earlier than now.

Clear the allocated memory in hyperv_dma_alloc().

vmbus(4), hvn(4), hvkbd(4): Fixed wait time for tsleep(9).

branches: 1.4.2;
Zero clear the allocated ring buffer for vmbus_channel.
This change makes Hyper-V's vmbus devices work properly even after reboot.

branches: 1.3.2;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.2.2;
Add __diagused.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

in many device attach paths, allocate memory with KM_SLEEP instead of KM_NOSLEEP
and remove code to handle failures that can no longer happen.

branches: 1.1.2; 1.1.6;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

branches: 1.2.2; 1.2.6;
Remove unused definition.

Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

branches: 1.1.2; 1.1.6;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.

Improve Hyper-V support.

vmbus(4):
- Added support for multichannel.

hvn(4):
- Added support for multichannel.
- Added support for change MTU.
- Added support for TX aggregation.
- Improve VLAN support.
- Improve checksum offload support.

Introduce per-cpu IDTs

This is realized by following modifications:
- Add IDT pages and its allocation maps for each cpu in "struct cpu_info"
- Load per-cpu IDTs at cpu_init_idt(struct cpu_info*)
- Copy the IDT entries for cpu0 to other CPUs at attach
- These are, for example, exceptions, db, system calls, etc.

And, added a kernel option named PCPU_IDT to enable the feature.

vmbus(4): Do not call hyperv_dma_alloc() in interrupt context.

The channel offer and rescind process is performed on another context.

hvn(4) can be added and deleted dynamically.

Get a Hyper-V virtual processor id in cpu_hatch().

Currently, it is got in config_interrupts context.
However, since it is required when attaching a device,
it is got earlier than now.

branches: 1.2.2;
Added drivers for Hyper-V Synthetic Keyboard and Video device.

branches: 1.1.2;
Added Microsoft Hyper-V support. It ported from OpenBSD and FreeBSD.

graphical console is not work on Gen.2 VM yet. To use the serial console,
enter "consdev com,0x3f8,115200" on efiboot.