virtio_ring: add a struct device forward declaration

The virtio_ring header file uses the struct device without a forward
declaration.

Signed-off-by: Shunsuke Mie <[email protected]>
Message-Id: <2023

virtio_ring: add a struct device forward declaration

The virtio_ring header file uses the struct device without a forward
declaration.

Signed-off-by: Shunsuke Mie <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio: add VIRTIO_F_NOTIFICATION_DATA feature support

According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
indicates that the driver passes extra data along with the queue
notification

virtio: add VIRTIO_F_NOTIFICATION_DATA feature support

According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
indicates that the driver passes extra data along with the queue
notifications.

In a split queue case, the extra data is 16-bit available index. In a
packed queue case, the extra data is 1-bit wrap counter and 15-bit
available index.

Add support for this feature for MMIO, channel I/O and modern PCI
transports.

Signed-off-by: Viktor Prutyanov <[email protected]>
Acked-by: Jason Wang <[email protected]>
Reviewed-by: Xuan Zhuo <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio_ring: per virtqueue dma device

This patch introduces a per virtqueue dma device. This will be used
for virtio devices whose virtqueue are backed by different underlayer
devices.

One example

virtio_ring: per virtqueue dma device

This patch introduces a per virtqueue dma device. This will be used
for virtio devices whose virtqueue are backed by different underlayer
devices.

One example is the vDPA that where the control virtqueue could be
implemented through software mediation.

Some of the work are actually done before since the helper like
vring_dma_device(). This work left are:

- Let vring_dma_device() return the per virtqueue dma device instead
of the vdev's parent.
- Allow passing a dma_device when creating the virtqueue through a new
helper, old vring creation helper will keep using vdev's parent.

Reviewed-by: Eli Cohen <[email protected]>
Tested-by: Eli Cohen <[email protected]>
Signed-off-by: Jason Wang <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio_ring: split: stop __vring_new_virtqueue as export symbol

There is currently only one place to reference __vring_new_virtqueue()
directly from the outside of virtio core. And here vring_new_vi

virtio_ring: split: stop __vring_new_virtqueue as export symbol

There is currently only one place to reference __vring_new_virtqueue()
directly from the outside of virtio core. And here vring_new_virtqueue()
can be used instead.

Subsequent patches will modify __vring_new_virtqueue, so stop it as an
export symbol for now.

Signed-off-by: Xuan Zhuo <[email protected]>
Acked-by: Jason Wang <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio_ring: sparse warning fixup

virtio_store_mb was built with split ring in mind so it accepts
__virtio16 arguments. Packed ring uses __le16 values, so sparse
complains. It's just a store with s

virtio_ring: sparse warning fixup

virtio_store_mb was built with split ring in mind so it accepts
__virtio16 arguments. Packed ring uses __le16 values, so sparse
complains. It's just a store with some barriers so let's convert it to
a macro, we don't loose too much type safety by doing that.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Cornelia Huck <[email protected]>

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virtio: Honour 'may_reduce_num' in vring_create_virtqueue

vring_create_virtqueue() allows the caller to specify via the
may_reduce_num parameter whether the vring code is allowed to
allocate a small

virtio: Honour 'may_reduce_num' in vring_create_virtqueue

vring_create_virtqueue() allows the caller to specify via the
may_reduce_num parameter whether the vring code is allowed to
allocate a smaller ring than specified.

However, the split ring allocation code tries to allocate a
smaller ring on allocation failure regardless of what the
caller specified. This may cause trouble for e.g. virtio-pci
in legacy mode, which does not support ring resizing. (The
packed ring code does not resize in any case.)

Let's fix this by bailing out immediately in the split ring code
if the requested size cannot be allocated and may_reduce_num has
not been specified.

While at it, fix a typo in the usage instructions.

Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API")
Cc: [email protected] # v4.6+
Signed-off-by: Cornelia Huck <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Halil Pasic <[email protected]>
Reviewed-by: Jens Freimann <[email protected]>

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virtio_ring: switch to dma_XX barriers for rpmsg

virtio is using barriers to order memory accesses, thus
dma_wmb/rmb is a good match.

Before
[mst@tuck linux]$ size drivers/virtio/virtio_ring.o
t

virtio_ring: switch to dma_XX barriers for rpmsg

virtio is using barriers to order memory accesses, thus
dma_wmb/rmb is a good match.

Before
[mst@tuck linux]$ size drivers/virtio/virtio_ring.o
text data bss dec hex filename
11392 820 0 12212 2fb4 drivers/virtio/virtio_ring.o

After
mst@tuck linux]$ size drivers/virtio/virtio_ring.o
text data bss dec hex filename
11284 820 0 12104 2f48 drivers/virtio/virtio_ring.o

Cc: Ohad Ben-Cohen <[email protected]>
Cc: Bjorn Andersson <[email protected]>
Cc: [email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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virtio: add context flag to find vqs

Allows maintaining extra context per vq. For ease of use, passing in
NULL is legal and disables the feature for all vqs.

Includes fixes by Christian for s390,

virtio: add context flag to find vqs

Allows maintaining extra context per vq. For ease of use, passing in
NULL is legal and disables the feature for all vqs.

Includes fixes by Christian for s390, acked by Cornelia.

Signed-off-by: Christian Borntraeger <[email protected]>
Acked-by: Cornelia Huck <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio: Add improved queue allocation API

This leaves vring_new_virtqueue alone for compatbility, but it
adds two new improved APIs:

vring_create_virtqueue: Creates a virtqueue backed by automatica

virtio: Add improved queue allocation API

This leaves vring_new_virtqueue alone for compatbility, but it
adds two new improved APIs:

vring_create_virtqueue: Creates a virtqueue backed by automatically
allocated coherent memory. (Some day it this could be extended to
support non-coherent memory, too, if there ends up being a platform
on which it's worthwhile.)

__vring_new_virtqueue: Creates a virtqueue with a manually-specified
layout. This should allow mic_virtio to work much more cleanly.

Signed-off-by: Andy Lutomirski <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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virtio_ring: use virt_store_mb

We need a full barrier after writing out event index, using
virt_store_mb there seems better than open-coding. As usual, we need a
wrapper to account for strong barri

virtio_ring: use virt_store_mb

We need a full barrier after writing out event index, using
virt_store_mb there seems better than open-coding. As usual, we need a
wrapper to account for strong barriers.

It's tempting to use this in vhost as well, for that, we'll
need a variant of smp_store_mb that works on __user pointers.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>

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virtio_ring: update weak barriers to use virt_xxx

virtio ring uses smp_wmb on SMP and wmb on !SMP,
the reason for the later being that it might be
talking to another kernel on the same SMP machine.

virtio_ring: update weak barriers to use virt_xxx

virtio ring uses smp_wmb on SMP and wmb on !SMP,
the reason for the later being that it might be
talking to another kernel on the same SMP machine.

This is exactly what virt_xxx barriers do,
so switch to these instead of homegrown ifdef hacks.

Cc: Peter Zijlstra <[email protected]>
Cc: Alexander Duyck <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>

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Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"

This reverts commit 9e1a27ea42691429e31f158cce6fc61bc79bb2e9.

While that commit optimizes !CONFIG_SMP, it mixes
up DMA and SMP concepts

Revert "virtio_ring: Update weak barriers to use dma_wmb/rmb"

This reverts commit 9e1a27ea42691429e31f158cce6fc61bc79bb2e9.

While that commit optimizes !CONFIG_SMP, it mixes
up DMA and SMP concepts, making the code hard
to figure out.

A better way to optimize this is with the new __smp_XXX
barriers.

As a first step, go back to full rmb/wmb barriers
for !SMP.
We switch to __smp_XXX barriers in the next patch.

Cc: Peter Zijlstra <[email protected]>
Cc: Alexander Duyck <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>

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virtio_ring: Update weak barriers to use dma_wmb/rmb

This change makes it so that instead of using smp_wmb/rmb which varies
depending on the kernel configuration we can can use dma_wmb/rmb which for

virtio_ring: Update weak barriers to use dma_wmb/rmb

This change makes it so that instead of using smp_wmb/rmb which varies
depending on the kernel configuration we can can use dma_wmb/rmb which for
most architectures should be equal to or slightly more strict than
smp_wmb/rmb.

The advantage to this is that these barriers are available to uniprocessor
builds as well so the performance should improve under such a
configuration.

Signed-off-by: Alexander Duyck <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio_ring: change host notification API

Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host n

virtio_ring: change host notification API

Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host notification seems to be one
prerequisite in order to be able to handle such errors in the context
where the kick is triggered.

This patch changes the notify API. The notify function must return a
bool return value. It returns false if the host notification failed.

Signed-off-by: Heinz Graalfs <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio: include asm/barrier explicitly

virtio_ring.h uses mb() and friends, make
it pull in asm/barrier.h itself, not rely
on other headers to do it.

Signed-off-by: Michael S. Tsirkin <[email protected]

virtio: include asm/barrier explicitly

virtio_ring.h uses mb() and friends, make
it pull in asm/barrier.h itself, not rely
on other headers to do it.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio_ring: expose virtio barriers for use in vringh.

The host side of ring needs this logic too.

Signed-off-by: Rusty Russell <[email protected]>

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Michae

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Michael Kerrisk <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Acked-by: Dave Jones <[email protected]>

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virtio-ring: move queue_index to vring_virtqueue

Instead of storing the queue index in transport-specific virtio structs,
this patch moves them to vring_virtqueue and introduces an helper to get
the

virtio-ring: move queue_index to vring_virtqueue

Instead of storing the queue index in transport-specific virtio structs,
this patch moves them to vring_virtqueue and introduces an helper to get
the value. This lets drivers simplify their management and tracing of
virtqueues.

Signed-off-by: Jason Wang <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio: harsher barriers for rpmsg.

We were cheating with our barriers; using the smp ones rather than the
real device ones. That was fine, until rpmsg came along, which is
used to talk to a real d

virtio: harsher barriers for rpmsg.

We were cheating with our barriers; using the smp ones rather than the
real device ones. That was fine, until rpmsg came along, which is
used to talk to a real device (a non-SMP CPU).

Unfortunately, just putting back the real barriers (reverting
d57ed95d) causes a performance regression on virtio-pci. In
particular, Amos reports netbench's TCP_RR over virtio_net CPU
utilization increased up to 35% while throughput went down by up to
14%.

By comparison, this branch is in the noise.

Reference: https://lkml.org/lkml/2011/12/11/22

Signed-off-by: Rusty Russell <[email protected]>

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virtio: modify vring_init and vring_size to take account of the layout containing *_event_idx

Based on the layout description in the comments, take account of
the *_event_idx in functions vring_init

virtio: modify vring_init and vring_size to take account of the layout containing *_event_idx

Based on the layout description in the comments, take account of
the *_event_idx in functions vring_init and vring_size.

Signed-off-by: Wang Sheng-Hui <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio ring: inline function to check for events

With the new used_event and avail_event and features, both
host and guest need similar logic to check whether events are
enabled, so it helps to put

virtio ring: inline function to check for events

With the new used_event and avail_event and features, both
host and guest need similar logic to check whether events are
enabled, so it helps to put the common code in the header.

Note that Xen has similar logic for notification hold-off
in include/xen/interface/io/ring.h with req_event and req_prod
corresponding to event_idx + 1 and new_idx respectively.
+1 comes from the fact that req_event and req_prod in Xen start at 1,
while event index in virtio starts at 0.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio: event index interface

Define a new feature bit for the guest and host to utilize
an event index (like Xen) instead if a flag bit to enable/disable
interrupts and kicks.

Signed-off-by: Micha

virtio: event index interface

Define a new feature bit for the guest and host to utilize
an event index (like Xen) instead if a flag bit to enable/disable
interrupts and kicks.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Rusty Russell <[email protected]>

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virtio: add full three-clause BSD text to headers.

It's unclear to me if it's important, but it's obviously causing my
technical colleages some headaches and I'd hate such imprecision to
slow virtio

virtio: add full three-clause BSD text to headers.

It's unclear to me if it's important, but it's obviously causing my
technical colleages some headaches and I'd hate such imprecision to
slow virtio adoption.

I've emailed this to all non-trivial contributors for approval, too.

Signed-off-by: Rusty Russell <[email protected]>
Acked-by: Grant Likely <[email protected]>
Acked-by: Ryan Harper <[email protected]>
Acked-by: Anthony Liguori <[email protected]>
Acked-by: Eric Van Hensbergen <[email protected]>
Acked-by: john cooper <[email protected]>
Acked-by: Aneesh Kumar K.V <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Acked-by: Fernando Luis Vazquez Cao <[email protected]>

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lguest and virtio: cleanup struct definitions to Linux style.

I've been doing this for years, and akpm picked me up on it about 12
months ago. lguest partly serves as example code, so let's do it R

lguest and virtio: cleanup struct definitions to Linux style.

I've been doing this for years, and akpm picked me up on it about 12
months ago. lguest partly serves as example code, so let's do it Right.

Also, remove two unused fields in struct vblk_info in the example launcher.

Signed-off-by: Rusty Russell <[email protected]>
Cc: Ingo Molnar <[email protected]>

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