vhost-scsi: Dynamically allocate scatterlists

We currently preallocate scatterlists which have 2048 entries for each
command. For a small device with just 1 queue this results in:

8 MB = 32 bytes p

vhost-scsi: Dynamically allocate scatterlists

We currently preallocate scatterlists which have 2048 entries for each
command. For a small device with just 1 queue this results in:

8 MB = 32 bytes per sg * 2048 entries * 128 cmd

When mq is turned on and we increase the virtqueue_size so we can handle
commands from multiple queues in parallel, then this can sky rocket.

This patch allows us to dynamically allocate the scatterlist like is done
with drivers like NVMe and SCSI.

For small IO (4-16K) IOPs testing, we didn't see any regressions, but
for throughput testing we sometimes saw a 2-5% regression when the
backend device was very fast (8 NVMe drives in a MD RAID0 config or a
memory backed device). As a result this patch makes the dynamic
allocation feature a modparam so userspace can decide how it wants to
balance mem use and perf.

Signed-off-by: Mike Christie <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Stefan Hajnoczi <[email protected]>

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vhost_task: Allow vhost layer to use copy_process

Qemu will create vhost devices in the kernel which perform network, SCSI,
etc IO and management operations from worker threads created by the
kthrea

vhost_task: Allow vhost layer to use copy_process

Qemu will create vhost devices in the kernel which perform network, SCSI,
etc IO and management operations from worker threads created by the
kthread API. Because the kthread API does a copy_process on the kthreadd
thread, the vhost layer has to use kthread_use_mm to access the Qemu
thread's memory and cgroup_attach_task_all to add itself to the Qemu
thread's cgroups, and it bypasses the RLIMIT_NPROC limit which can result
in VMs creating more threads than the admin expected.

This patch adds a new struct vhost_task which can be used instead of
kthreads. They allow the vhost layer to use copy_process and inherit
the userspace process's mm and cgroups, the task is accounted for
under the userspace's nproc count and can be seen in its process tree,
and other features like namespaces work and are inherited by default.

Signed-off-by: Mike Christie <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

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vhost_vdpa: implement IRQ offloading in vhost_vdpa

This patch introduce a set of functions for setup/unsetup
and update irq offloading respectively by register/unregister
and re-register the irq_byp

vhost_vdpa: implement IRQ offloading in vhost_vdpa

This patch introduce a set of functions for setup/unsetup
and update irq offloading respectively by register/unregister
and re-register the irq_bypass_producer.

With these functions, this commit can setup/unsetup
irq offloading through setting DRIVER_OK/!DRIVER_OK, and
update irq offloading through SET_VRING_CALL.

Signed-off-by: Zhu Lingshan <[email protected]>
Suggested-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasi

treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <[email protected]>

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vhost: revert "vhost: disable for OABI"

This reverts commit d085eb8ce727 ("vhost: disable for OABI")
With commit "virtio: force spec specified alignment on types"
in place, we force proper alignment

vhost: revert "vhost: disable for OABI"

This reverts commit d085eb8ce727 ("vhost: disable for OABI")
With commit "virtio: force spec specified alignment on types"
in place, we force proper alignment for all structures,
so there's no longer a reason to blacklist OABI.

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

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vhost: disable for OABI

vhost is currently broken on the some ARM configs.

The reason is that the ring element addresses are passed between
components with different alignments assumptions. Thus, i

vhost: disable for OABI

vhost is currently broken on the some ARM configs.

The reason is that the ring element addresses are passed between
components with different alignments assumptions. Thus, if
guest selects a pointer and host then gets and dereferences
it, then alignment assumed by the host's compiler might be
greater than the actual alignment of the pointer.
compiler on the host from assuming pointer is aligned.

This actually triggers on ARM with -mabi=apcs-gnu - which is a
deprecated configuration. With this OABI, compiler assumes that
all structures are 4 byte aligned - which is stronger than
virtio guarantees for available and used rings, which are
merely 2 bytes. Thus a guest without -mabi=apcs-gnu running
on top of host with -mabi=apcs-gnu will be broken.

The correct fix is to force alignment of structures - however
that is an intrusive fix that's best deferred until the next release.

We didn't previously support such ancient systems at all - this surfaced
after vdpa support prompted removing dependency of vhost on
VIRTULIZATION. So for now, let's just add something along the lines of

depends on !ARM || AEABI

to the virtio Kconfig declaration, and add a comment that it has to do
with struct member alignment.

Note: we can't make VHOST and VHOST_RING themselves have
a dependency since these are selected. Add a new symbol for that.

We should be able to drop this dependency down the road.

Fixes: 20c384f1ea1a0bc7 ("vhost: refine vhost and vringh kconfig")
Suggested-by: Ard Biesheuvel <[email protected]>
Suggested-by: Richard Earnshaw <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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vdpa: make vhost, virtio depend on menu

If user did not configure any vdpa drivers, neither vhost
nor virtio vdpa are going to be useful. So there's no point
in prompting for these and selecting vdp

vdpa: make vhost, virtio depend on menu

If user did not configure any vdpa drivers, neither vhost
nor virtio vdpa are going to be useful. So there's no point
in prompting for these and selecting vdpa core automatically.
Simplify configuration by making virtio and vhost vdpa
drivers depend on vdpa menu entry. Once done, we no longer
need a separate menu entry, so also get rid of this.
While at it, fix up the IFC entry: VDPA->vDPA for consistency
with other places.

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

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virtio/test: fix up after IOTLB changes

Allow building vringh without IOTLB (that's the case for userspace
builds, will be useful for CAIF/VOD down the road too).
Update for API tweaks.
Don't includ

virtio/test: fix up after IOTLB changes

Allow building vringh without IOTLB (that's the case for userspace
builds, will be useful for CAIF/VOD down the road too).
Update for API tweaks.
Don't include vringh with userspace builds.

Cc: Jason Wang <[email protected]>
Cc: Eugenio Pérez <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Acked-by: Jason Wang <[email protected]>

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vhost: introduce vDPA-based backend

This patch introduces a vDPA-based vhost backend. This backend is
built on top of the same interface defined in virtio-vDPA and provides
a generic vhost interface

vhost: introduce vDPA-based backend

This patch introduces a vDPA-based vhost backend. This backend is
built on top of the same interface defined in virtio-vDPA and provides
a generic vhost interface for userspace to accelerate the virtio
devices in guest.

This backend is implemented as a vDPA device driver on top of the same
ops used in virtio-vDPA. It will create char device entry named
vhost-vdpa-$index for userspace to use. Userspace can use vhost ioctls
on top of this char device to setup the backend.

Vhost ioctls are extended to make it type agnostic and behave like a
virtio device, this help to eliminate type specific API like what
vhost_net/scsi/vsock did:

- VHOST_VDPA_GET_DEVICE_ID: get the virtio device ID which is defined
by virtio specification to differ from different type of devices
- VHOST_VDPA_GET_VRING_NUM: get the maximum size of virtqueue
supported by the vDPA device
- VHSOT_VDPA_SET/GET_STATUS: set and get virtio status of vDPA device
- VHOST_VDPA_SET/GET_CONFIG: access virtio config space
- VHOST_VDPA_SET_VRING_ENABLE: enable a specific virtqueue

For memory mapping, IOTLB API is mandated for vhost-vDPA which means
userspace drivers are required to use
VHOST_IOTLB_UPDATE/VHOST_IOTLB_INVALIDATE to add or remove mapping for
a specific userspace memory region.

The vhost-vDPA API is designed to be type agnostic, but it allows net
device only in current stage. Due to the lacking of control virtqueue
support, some features were filter out by vhost-vdpa.

We will enable more features and devices in the near future.

Signed-off-by: Tiwei Bie <[email protected]>
Signed-off-by: Eugenio Pérez <[email protected]>
Signed-off-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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vringh: IOTLB support

This patch implements the third memory accessor for vringh besides
current kernel and userspace accessors. This idea is to allow vringh
to do the address translation through an

vringh: IOTLB support

This patch implements the third memory accessor for vringh besides
current kernel and userspace accessors. This idea is to allow vringh
to do the address translation through an IOTLB which is implemented
via vhost_map interval tree. Users should setup and IOVA to PA mapping
in this IOTLB.

This allows us to:

- Use vringh to access virtqueues with vIOMMU
- Use vringh to implement software virtqueues for vDPA devices

Signed-off-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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vhost: factor out IOTLB

This patch factors out IOTLB into a dedicated module in order to be
reused by other modules like vringh. User may choose to enable the
automatic retiring by specifying VHOST_

vhost: factor out IOTLB

This patch factors out IOTLB into a dedicated module in order to be
reused by other modules like vringh. User may choose to enable the
automatic retiring by specifying VHOST_IOTLB_FLAG_RETIRE flag to fit
for the case of vhost device IOTLB implementation.

Signed-off-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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vhost: refine vhost and vringh kconfig

Currently, CONFIG_VHOST depends on CONFIG_VIRTUALIZATION. But vhost is
not necessarily for VM since it's a generic userspace and kernel
communication protocol.

vhost: refine vhost and vringh kconfig

Currently, CONFIG_VHOST depends on CONFIG_VIRTUALIZATION. But vhost is
not necessarily for VM since it's a generic userspace and kernel
communication protocol. Such dependency may prevent archs without
virtualization support from using vhost.

To solve this, a dedicated vhost menu is created under drivers so
CONIFG_VHOST can be decoupled out of CONFIG_VIRTUALIZATION.

While at it, also squash Kconfig.vringh into vhost Kconfig file. This
avoids the trick of conditional inclusion from VOP or CAIF. Then it
will be easier to introduce new vringh users and common dependency for
both vringh and vhost.

Signed-off-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

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treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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vhost: allow vhost-scsi driver to be built-in

It's useful to allow vhost-scsi to be built-in when testing vhost in L1
+ L2 VMs and booting L1 VM with QEMU '-kernel' option.

Signed-off-by: Greg Edwa

vhost: allow vhost-scsi driver to be built-in

It's useful to allow vhost-scsi to be built-in when testing vhost in L1
+ L2 VMs and booting L1 VM with QEMU '-kernel' option.

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

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tap: tap as an independent module

This patch makes tap a separate module for other types of virtual interfaces, for example,
ipvlan to use.

Signed-off-by: Sainath Grandhi <[email protected]

tap: tap as an independent module

This patch makes tap a separate module for other types of virtual interfaces, for example,
ipvlan to use.

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

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vhost: split out vringh Kconfig

vringh is pulled in by caif and mic, but the other
vhost config does not need to be there.
In particular, it makes no sense to have vhost net/scsi/sock
under caif/mic

vhost: split out vringh Kconfig

vringh is pulled in by caif and mic, but the other
vhost config does not need to be there.
In particular, it makes no sense to have vhost net/scsi/sock
under caif/mic.

Create a separate Kconfig file and put vringh bits there.

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

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VSOCK: Add Makefile and Kconfig

Enable virtio-vsock and vhost-vsock.

Signed-off-by: Asias He <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Michael S. Tsirki

VSOCK: Add Makefile and Kconfig

Enable virtio-vsock and vhost-vsock.

Signed-off-by: Asias He <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>

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vhost: drop vringh dependency

vringh isn't used by vhost net or scsi - it's used
by CAIF only at the moment. Drop the dependency.

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

Revert "Merge branch 'vsock-virtio'"

This reverts commit 0d76d6e8b2507983a2cae4c09880798079007421 and merge
commit c402293bd76fbc93e52ef8c0947ab81eea3ae019, reversing changes made
to c89359a42e2a496

Revert "Merge branch 'vsock-virtio'"

This reverts commit 0d76d6e8b2507983a2cae4c09880798079007421 and merge
commit c402293bd76fbc93e52ef8c0947ab81eea3ae019, reversing changes made
to c89359a42e2a49656451569c382eed63e781153c.

The virtio-vsock device specification is not finalized yet. Michael
Tsirkin voiced concerned about merging this code when the hardware
interface (and possibly the userspace interface) could still change.

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

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VSOCK: Add Makefile and Kconfig

Enable virtio-vsock and vhost-vsock.

Signed-off-by: Asias He <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: David S. Miller <

VSOCK: Add Makefile and Kconfig

Enable virtio-vsock and vhost-vsock.

Signed-off-by: Asias He <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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vhost: cross-endian support for legacy devices

This patch brings cross-endian support to vhost when used to implement
legacy virtio devices. Since it is a relatively rare situation, the
feature avai

vhost: cross-endian support for legacy devices

This patch brings cross-endian support to vhost when used to implement
legacy virtio devices. Since it is a relatively rare situation, the
feature availability is controlled by a kernel config option (not set
by default).

The vq->is_le boolean field is added to cache the endianness to be
used for ring accesses. It defaults to native endian, as expected
by legacy virtio devices. When the ring gets active, we force little
endian if the device is modern. When the ring is deactivated, we
revert to the native endian default.

If cross-endian was compiled in, a vq->user_be boolean field is added
so that userspace may request a specific endianness. This field is
used to override the default when activating the ring of a legacy
device. It has no effect on modern devices.

Signed-off-by: Greg Kurz <[email protected]>

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

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vhost: Make vhost a separate module

Currently, vhost-net and vhost-scsi are sharing the vhost core code.
However, vhost-scsi shares the code by including the vhost.c file
directly.

Making vhost a s

vhost: Make vhost a separate module

Currently, vhost-net and vhost-scsi are sharing the vhost core code.
However, vhost-scsi shares the code by including the vhost.c file
directly.

Making vhost a separate module makes it is easier to share code with
other vhost devices.

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

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vhost_scsi: module rename

Rename module and update Kconfig and Makefile.
Add alias for compatibility with old userspace
scripts if any.

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

vhost_scsi: module rename

Rename module and update Kconfig and Makefile.
Add alias for compatibility with old userspace
scripts if any.

Signed-off-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Asias He <[email protected]>
Acked-by: Nicholas Bellinger <[email protected]>

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vringh: host-side implementation of virtio rings.

Getting use of virtio rings correct is tricky, and a recent patch saw
an implementation of in-kernel rings (as separate from userspace).

This abstr

vringh: host-side implementation of virtio rings.

Getting use of virtio rings correct is tricky, and a recent patch saw
an implementation of in-kernel rings (as separate from userspace).

This abstracts the business of dealing with the virtio ring layout
from the access (userspace or direct); to do this, we use function
pointers, which gcc inlines correctly.

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

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drivers/vhost: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Li

drivers/vhost: remove depends on CONFIG_EXPERIMENTAL

The CONFIG_EXPERIMENTAL config item has not carried much meaning for a
while now and is almost always enabled by default. As agreed during the
Linux kernel summit, remove it from any "depends on" lines in Kconfigs.

Acked-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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