Linux Virtualization - Apr 2020 - [PATCH V2] vhost: do not enable VHOST_MENU by default

On 2020/4/17 ??6:55, Michael S. Tsirkin wrote:
> On Wed, Apr 15, 2020 at 10:43:56AM +0800, Jason Wang wrote:
>> We try to keep the defconfig untouched after decoupling CONFIG_VHOST
>> out of CONFIG_VIRTUALIZATION in commit 20c384f1ea1a
>> ("vhost: refine vhost and vringh kconfig") by enabling
VHOST_MENU by
>> default. Then the defconfigs can keep enabling CONFIG_VHOST_NET
>> without the caring of CONFIG_VHOST.
>>
>> But this will leave a "CONFIG_VHOST_MENU=y" in all defconfigs
and even
>> for the ones that doesn't want vhost. So it actually shifts the
>> burdens to the maintainers of all other to add "CONFIG_VHOST_MENU
is
>> not set". So this patch tries to enable CONFIG_VHOST explicitly in
>> defconfigs that enables CONFIG_VHOST_NET and CONFIG_VHOST_VSOCK.
>>
>> Acked-by: Christian Borntraeger<borntraeger at de.ibm.com> 
(s390)
>> Acked-by: Michael Ellerman<mpe at ellerman.id.au>  (powerpc)
>> Cc: Thomas Bogendoerfer<tsbogend at alpha.franken.de>
>> Cc: Benjamin Herrenschmidt<benh at kernel.crashing.org>
>> Cc: Paul Mackerras<paulus at samba.org>
>> Cc: Michael Ellerman<mpe at ellerman.id.au>
>> Cc: Heiko Carstens<heiko.carstens at de.ibm.com>
>> Cc: Vasily Gorbik<gor at linux.ibm.com>
>> Cc: Christian Borntraeger<borntraeger at de.ibm.com>
>> Reported-by: Geert Uytterhoeven<geert at linux-m68k.org>
>> Signed-off-by: Jason Wang<jasowang at redhat.com>
> I rebased this on top of OABI fix since that
> seems more orgent to fix.
> Pushed to my vhost branch pls take a look and
> if possible test.
> Thanks!

I test this patch by generating the defconfigs that wants vhost_net or 
vhost_vsock. All looks fine.

But having CONFIG_VHOST_DPN=y may end up with the similar situation that 
this patch want to address.

Maybe we can let CONFIG_VHOST depends on !ARM || AEABI then add another 
menuconfig for VHOST_RING and do something similar?

Thanks

On Fri, Apr 17, 2020 at 11:12:14AM +0800, Jason Wang
wrote:
> 
> On 2020/4/17 ??6:55, Michael S. Tsirkin wrote:
> > On Wed, Apr 15, 2020 at 10:43:56AM +0800, Jason Wang wrote:
> > > We try to keep the defconfig untouched after decoupling
CONFIG_VHOST
> > > out of CONFIG_VIRTUALIZATION in commit 20c384f1ea1a
> > > ("vhost: refine vhost and vringh kconfig") by enabling
VHOST_MENU by
> > > default. Then the defconfigs can keep enabling CONFIG_VHOST_NET
> > > without the caring of CONFIG_VHOST.
> > > 
> > > But this will leave a "CONFIG_VHOST_MENU=y" in all
defconfigs and even
> > > for the ones that doesn't want vhost. So it actually shifts
the
> > > burdens to the maintainers of all other to add
"CONFIG_VHOST_MENU is
> > > not set". So this patch tries to enable CONFIG_VHOST
explicitly in
> > > defconfigs that enables CONFIG_VHOST_NET and CONFIG_VHOST_VSOCK.
> > > 
> > > Acked-by: Christian Borntraeger<borntraeger at de.ibm.com> 
(s390)
> > > Acked-by: Michael Ellerman<mpe at ellerman.id.au> 
(powerpc)
> > > Cc: Thomas Bogendoerfer<tsbogend at alpha.franken.de>
> > > Cc: Benjamin Herrenschmidt<benh at kernel.crashing.org>
> > > Cc: Paul Mackerras<paulus at samba.org>
> > > Cc: Michael Ellerman<mpe at ellerman.id.au>
> > > Cc: Heiko Carstens<heiko.carstens at de.ibm.com>
> > > Cc: Vasily Gorbik<gor at linux.ibm.com>
> > > Cc: Christian Borntraeger<borntraeger at de.ibm.com>
> > > Reported-by: Geert Uytterhoeven<geert at linux-m68k.org>
> > > Signed-off-by: Jason Wang<jasowang at redhat.com>
> > I rebased this on top of OABI fix since that
> > seems more orgent to fix.
> > Pushed to my vhost branch pls take a look and
> > if possible test.
> > Thanks!
> 
> 
> I test this patch by generating the defconfigs that wants vhost_net or
> vhost_vsock. All looks fine.
> 
> But having CONFIG_VHOST_DPN=y may end up with the similar situation that
> this patch want to address.
> Maybe we can let CONFIG_VHOST depends on !ARM || AEABI then add another
> menuconfig for VHOST_RING and do something similar?
> 
> Thanks
Sorry I don't understand. After this patch CONFIG_VHOST_DPN is just
an internal variable for the OABI fix. I kept it separate
so it's easy to revert for 5.8. Yes we could squash it into
VHOST directly but I don't see how that changes logic at all.

-- 
MST

On 2020/4/17 ??2:33, Michael S. Tsirkin wrote:
> On Fri, Apr 17, 2020 at 11:12:14AM +0800, Jason Wang wrote:
>> On 2020/4/17 ??6:55, Michael S. Tsirkin wrote:
>>> On Wed, Apr 15, 2020 at 10:43:56AM +0800, Jason Wang wrote:
>>>> We try to keep the defconfig untouched after decoupling
CONFIG_VHOST
>>>> out of CONFIG_VIRTUALIZATION in commit 20c384f1ea1a
>>>> ("vhost: refine vhost and vringh kconfig") by
enabling VHOST_MENU by
>>>> default. Then the defconfigs can keep enabling CONFIG_VHOST_NET
>>>> without the caring of CONFIG_VHOST.
>>>>
>>>> But this will leave a "CONFIG_VHOST_MENU=y" in all
defconfigs and even
>>>> for the ones that doesn't want vhost. So it actually shifts
the
>>>> burdens to the maintainers of all other to add
"CONFIG_VHOST_MENU is
>>>> not set". So this patch tries to enable CONFIG_VHOST
explicitly in
>>>> defconfigs that enables CONFIG_VHOST_NET and
CONFIG_VHOST_VSOCK.
>>>>
>>>> Acked-by: Christian Borntraeger<borntraeger at
de.ibm.com>  (s390)
>>>> Acked-by: Michael Ellerman<mpe at ellerman.id.au> 
(powerpc)
>>>> Cc: Thomas Bogendoerfer<tsbogend at alpha.franken.de>
>>>> Cc: Benjamin Herrenschmidt<benh at kernel.crashing.org>
>>>> Cc: Paul Mackerras<paulus at samba.org>
>>>> Cc: Michael Ellerman<mpe at ellerman.id.au>
>>>> Cc: Heiko Carstens<heiko.carstens at de.ibm.com>
>>>> Cc: Vasily Gorbik<gor at linux.ibm.com>
>>>> Cc: Christian Borntraeger<borntraeger at de.ibm.com>
>>>> Reported-by: Geert Uytterhoeven<geert at linux-m68k.org>
>>>> Signed-off-by: Jason Wang<jasowang at redhat.com>
>>> I rebased this on top of OABI fix since that
>>> seems more orgent to fix.
>>> Pushed to my vhost branch pls take a look and
>>> if possible test.
>>> Thanks!
>>
>> I test this patch by generating the defconfigs that wants vhost_net or
>> vhost_vsock. All looks fine.
>>
>> But having CONFIG_VHOST_DPN=y may end up with the similar situation
that
>> this patch want to address.
>> Maybe we can let CONFIG_VHOST depends on !ARM || AEABI then add another
>> menuconfig for VHOST_RING and do something similar?
>>
>> Thanks
> Sorry I don't understand. After this patch CONFIG_VHOST_DPN is just
> an internal variable for the OABI fix. I kept it separate
> so it's easy to revert for 5.8. Yes we could squash it into
> VHOST directly but I don't see how that changes logic at all.

Sorry for being unclear.

I meant since it was enabled by default, "CONFIG_VHOST_DPN=y" will be 
left in the defconfigs. This requires the arch maintainers to add 
"CONFIG_VHOST_VDPN is not set". (Geert complains about this)

Thanks

>