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SubjectRe: [PATCH V9 1/9] vhost: refine vhost and vringh kconfig
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On 2020/4/1 下午10:13, Michael S. Tsirkin wrote:
> On Wed, Apr 01, 2020 at 10:08:59PM +0800, Jason Wang wrote:
>> On 2020/4/1 下午9:22, Michael S. Tsirkin wrote:
>>> On Thu, Mar 26, 2020 at 10:01:17PM +0800, Jason Wang wrote:
>>>> 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 <jasowang@redhat.com>
>>> Is this just so we can drop the dependency on CONFIG_VIRTUALIZATION?
>>> If yes what happens if we drop this patch?
>>
>> The problem is that then VHOST_RING must depend on CONFIG_VIRTUALIZATION
>> (which enable VHOST_IOTLB) to work.
>>
>> But it looks to me CAIF and VOP doesn't requires CONFIG_VIRTUALIZATION.
> How about stubs for IOTLB so VHOST_RING does not depend on VHOST_IOTLB?


That could work.


> I'm pretty sure neither user of vringh can actually use IOTLB, it's a
> software only thing.


Right.


>
>>> Given the impact it had I'd like to defer it till next release if
>>> possible.
>>>
>>>
>>>> ---
>>>> arch/arm/kvm/Kconfig | 2 --
>>>> arch/arm64/kvm/Kconfig | 2 --
>>>> arch/mips/kvm/Kconfig | 2 --
>>>> arch/powerpc/kvm/Kconfig | 2 --
>>>> arch/s390/kvm/Kconfig | 4 ----
>>>> arch/x86/kvm/Kconfig | 4 ----
>>>> drivers/Kconfig | 2 ++
>>>> drivers/misc/mic/Kconfig | 4 ----
>>>> drivers/net/caif/Kconfig | 4 ----
>>>> drivers/vhost/Kconfig | 23 ++++++++++++++---------
>>>> drivers/vhost/Kconfig.vringh | 6 ------
>>>> 11 files changed, 16 insertions(+), 39 deletions(-)
>>>> delete mode 100644 drivers/vhost/Kconfig.vringh
>>>>
>>>> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
>>>> index f591026347a5..be97393761bf 100644
>>>> --- a/arch/arm/kvm/Kconfig
>>>> +++ b/arch/arm/kvm/Kconfig
>>>> @@ -54,6 +54,4 @@ config KVM_ARM_HOST
>>>> ---help---
>>>> Provides host support for ARM processors.
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
>>>> index a475c68cbfec..449386d76441 100644
>>>> --- a/arch/arm64/kvm/Kconfig
>>>> +++ b/arch/arm64/kvm/Kconfig
>>>> @@ -64,6 +64,4 @@ config KVM_ARM_PMU
>>>> config KVM_INDIRECT_VECTORS
>>>> def_bool KVM && (HARDEN_BRANCH_PREDICTOR || HARDEN_EL2_VECTORS)
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig
>>>> index eac25aef21e0..b91d145aa2d5 100644
>>>> --- a/arch/mips/kvm/Kconfig
>>>> +++ b/arch/mips/kvm/Kconfig
>>>> @@ -72,6 +72,4 @@ config KVM_MIPS_DEBUG_COP0_COUNTERS
>>>> If unsure, say N.
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig
>>>> index 711fca9bc6f0..12885eda324e 100644
>>>> --- a/arch/powerpc/kvm/Kconfig
>>>> +++ b/arch/powerpc/kvm/Kconfig
>>>> @@ -204,6 +204,4 @@ config KVM_XIVE
>>>> default y
>>>> depends on KVM_XICS && PPC_XIVE_NATIVE && KVM_BOOK3S_HV_POSSIBLE
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
>>>> index d3db3d7ed077..def3b60f1fe8 100644
>>>> --- a/arch/s390/kvm/Kconfig
>>>> +++ b/arch/s390/kvm/Kconfig
>>>> @@ -55,8 +55,4 @@ config KVM_S390_UCONTROL
>>>> If unsure, say N.
>>>> -# OK, it's a little counter-intuitive to do this, but it puts it neatly under
>>>> -# the virtualization menu.
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
>>>> index 991019d5eee1..0dfe70e17af9 100644
>>>> --- a/arch/x86/kvm/Kconfig
>>>> +++ b/arch/x86/kvm/Kconfig
>>>> @@ -94,8 +94,4 @@ config KVM_MMU_AUDIT
>>>> This option adds a R/W kVM module parameter 'mmu_audit', which allows
>>>> auditing of KVM MMU events at runtime.
>>>> -# OK, it's a little counter-intuitive to do this, but it puts it neatly under
>>>> -# the virtualization menu.
>>>> -source "drivers/vhost/Kconfig"
>>>> -
>>>> endif # VIRTUALIZATION
>>>> diff --git a/drivers/Kconfig b/drivers/Kconfig
>>>> index 8befa53f43be..7a6d8b2b68b4 100644
>>>> --- a/drivers/Kconfig
>>>> +++ b/drivers/Kconfig
>>>> @@ -138,6 +138,8 @@ source "drivers/virt/Kconfig"
>>>> source "drivers/virtio/Kconfig"
>>>> +source "drivers/vhost/Kconfig"
>>>> +
>>>> source "drivers/hv/Kconfig"
>>>> source "drivers/xen/Kconfig"
>>>> diff --git a/drivers/misc/mic/Kconfig b/drivers/misc/mic/Kconfig
>>>> index b6841ba6d922..8f201d019f5a 100644
>>>> --- a/drivers/misc/mic/Kconfig
>>>> +++ b/drivers/misc/mic/Kconfig
>>>> @@ -133,8 +133,4 @@ config VOP
>>>> OS and tools for MIC to use with this driver are available from
>>>> <http://software.intel.com/en-us/mic-developer>.
>>>> -if VOP
>>>> -source "drivers/vhost/Kconfig.vringh"
>>>> -endif
>>>> -
>>>> endmenu
>>>> diff --git a/drivers/net/caif/Kconfig b/drivers/net/caif/Kconfig
>>>> index e74e2bb61236..9db0570c5beb 100644
>>>> --- a/drivers/net/caif/Kconfig
>>>> +++ b/drivers/net/caif/Kconfig
>>>> @@ -58,8 +58,4 @@ config CAIF_VIRTIO
>>>> ---help---
>>>> The CAIF driver for CAIF over Virtio.
>>>> -if CAIF_VIRTIO
>>>> -source "drivers/vhost/Kconfig.vringh"
>>>> -endif
>>>> -
>>>> endif # CAIF_DRIVERS
>>>> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
>>>> index 3d03ccbd1adc..4aef10a54cd1 100644
>>>> --- a/drivers/vhost/Kconfig
>>>> +++ b/drivers/vhost/Kconfig
>>>> @@ -1,8 +1,20 @@
>>>> # SPDX-License-Identifier: GPL-2.0-only
>>>> +config VHOST_RING
>>>> + tristate
>>>> + help
>>>> + This option is selected by any driver which needs to access
>>>> + the host side of a virtio ring.
>>>> +
>>>> +menuconfig VHOST
>>>> + tristate "Host kernel accelerator for virtio (VHOST)"
>>>> + help
>>>> + This option is selected by any driver which needs to access
>>>> + the core of vhost.
>>>> +if VHOST
>>>> +
>>> The description here is wrong, isn't it?
>>> VHOST and VHOST_RING are no longer selected, right?
>>
>> For VHOST not currently.
> Can we just bring it back and select it?


Right, so if bring it back, we don't even need the stub.

How about something like attached?

Thanks


>
>> For VHOST_RING, it was selected by CAIF, VOP and VDPASIM.
>>
>> Thanks
>>
>>
>>>
>>>> config VHOST_NET
>>>> tristate "Host kernel accelerator for virtio net"
>>>> depends on NET && EVENTFD && (TUN || !TUN) && (TAP || !TAP)
>>>> - select VHOST
>>>> ---help---
>>>> This kernel module can be loaded in host kernel to accelerate
>>>> guest networking with virtio_net. Not to be confused with virtio_net
>>>> @@ -14,7 +26,6 @@ config VHOST_NET
>>>> config VHOST_SCSI
>>>> tristate "VHOST_SCSI TCM fabric driver"
>>>> depends on TARGET_CORE && EVENTFD
>>>> - select VHOST
>>>> default n
>>>> ---help---
>>>> Say M here to enable the vhost_scsi TCM fabric module
>>>> @@ -24,7 +35,6 @@ config VHOST_VSOCK
>>>> tristate "vhost virtio-vsock driver"
>>>> depends on VSOCKETS && EVENTFD
>>>> select VIRTIO_VSOCKETS_COMMON
>>>> - select VHOST
>>>> default n
>>>> ---help---
>>>> This kernel module can be loaded in the host kernel to provide AF_VSOCK
>>>> @@ -34,12 +44,6 @@ config VHOST_VSOCK
>>>> To compile this driver as a module, choose M here: the module will be called
>>>> vhost_vsock.
>>>> -config VHOST
>>>> - tristate
>>>> - ---help---
>>>> - This option is selected by any driver which needs to access
>>>> - the core of vhost.
>>>> -
>>>> config VHOST_CROSS_ENDIAN_LEGACY
>>>> bool "Cross-endian support for vhost"
>>>> default n
>>>> @@ -54,3 +58,4 @@ config VHOST_CROSS_ENDIAN_LEGACY
>>>> adds some overhead, it is disabled by default.
>>>> If unsure, say "N".
>>>> +endif
>>>> diff --git a/drivers/vhost/Kconfig.vringh b/drivers/vhost/Kconfig.vringh
>>>> deleted file mode 100644
>>>> index c1fe36a9b8d4..000000000000
>>>> --- a/drivers/vhost/Kconfig.vringh
>>>> +++ /dev/null
>>>> @@ -1,6 +0,0 @@
>>>> -# SPDX-License-Identifier: GPL-2.0-only
>>>> -config VHOST_RING
>>>> - tristate
>>>> - ---help---
>>>> - This option is selected by any driver which needs to access
>>>> - the host side of a virtio ring.
>>>> --
>>>> 2.20.1
From 9b3a5d23b8bf6b0a11e65e688335d782f8e6aa5c Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang@redhat.com>
Date: Wed, 1 Apr 2020 22:17:27 +0800
Subject: [PATCH] vhost: let CONFIG_VHOST to be selected by drivers

The defconfig on some archs enable vhost_net or vhost_vsock by
default. So instead of adding CONFIG_VHOST=m to all of those files,
simply letting CONFIG_VHOST to be selected by all of the vhost
drivers. This fixes the build on the archs with CONFIG_VHOST_NET=m in
their defconfig.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/Kconfig | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index 2523a1d4290a..362b832f5338 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -11,19 +11,23 @@ config VHOST_RING
This option is selected by any driver which needs to access
the host side of a virtio ring.

-menuconfig VHOST
- tristate "Host kernel accelerator for virtio (VHOST)"
- depends on EVENTFD
+config VHOST
+ tristate
select VHOST_IOTLB
help
This option is selected by any driver which needs to access
the core of vhost.

-if VHOST
+menuconfig VHOST_MENU
+ bool "VHOST drivers"
+ default y
+
+if VHOST_MENU

config VHOST_NET
tristate "Host kernel accelerator for virtio net"
depends on NET && EVENTFD && (TUN || !TUN) && (TAP || !TAP)
+ select VHOST
---help---
This kernel module can be loaded in host kernel to accelerate
guest networking with virtio_net. Not to be confused with virtio_net
@@ -35,6 +39,7 @@ config VHOST_NET
config VHOST_SCSI
tristate "VHOST_SCSI TCM fabric driver"
depends on TARGET_CORE && EVENTFD
+ select VHOST
default n
---help---
Say M here to enable the vhost_scsi TCM fabric module
@@ -43,6 +48,7 @@ config VHOST_SCSI
config VHOST_VSOCK
tristate "vhost virtio-vsock driver"
depends on VSOCKETS && EVENTFD
+ select VHOST
select VIRTIO_VSOCKETS_COMMON
default n
---help---
@@ -56,6 +62,7 @@ config VHOST_VSOCK
config VHOST_VDPA
tristate "Vhost driver for vDPA-based backend"
depends on EVENTFD
+ select VHOST
select VDPA
help
This kernel module can be loaded in host kernel to accelerate
--
2.20.1
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