From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH V2] vhost: do not enable VHOST_MENU by default References: <20200415024356.23751-1-jasowang@redhat.com> <20200416185426-mutt-send-email-mst@kernel.org> <20200417022929-mutt-send-email-mst@kernel.org> <4274625d-6feb-81b6-5b0a-695229e7c33d@redhat.com> <20200417042912-mutt-send-email-mst@kernel.org> <20200417044230-mutt-send-email-mst@kernel.org> <73843240-3040-655d-baa9-683341ed4786@redhat.com> <20200417045454-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <2f5681bb-a8e6-fe73-57f5-24de7a5a72e8@redhat.com> Date: Fri, 17 Apr 2020 17:32:57 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org List-ID: To: Geert Uytterhoeven , "Michael S. Tsirkin" Cc: "open list:BROADCOM NVRAM DRIVER" , Linux Kernel Mailing List , linuxppc-dev , linux-s390 , KVM list , virtualization@lists.linux-foundation.org, netdev , Thomas Bogendoerfer , Benjamin Herrenschmidt , Paul Mackerras , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Michael Ellerman On 2020/4/17 =E4=B8=8B=E5=8D=885:25, Geert Uytterhoeven wrote: > Hi Michael, > > On Fri, Apr 17, 2020 at 10:57 AM Michael S. Tsirkin wr= ote: >> On Fri, Apr 17, 2020 at 04:51:19PM +0800, Jason Wang wrote: >>> On 2020/4/17 =E4=B8=8B=E5=8D=884:46, Michael S. Tsirkin wrote: >>>> On Fri, Apr 17, 2020 at 04:39:49PM +0800, Jason Wang wrote: >>>>> On 2020/4/17 =E4=B8=8B=E5=8D=884:29, Michael S. Tsirkin wrote: >>>>>> On Fri, Apr 17, 2020 at 03:36:52PM +0800, Jason Wang wrote: >>>>>>> On 2020/4/17 =E4=B8=8B=E5=8D=882:33, Michael S. Tsirkin wrote: >>>>>>>> On Fri, Apr 17, 2020 at 11:12:14AM +0800, Jason Wang wrote: >>>>>>>>> On 2020/4/17 =E4=B8=8A=E5=8D=886:55, 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 CONFI= G_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_N= ET >>>>>>>>>>> without the caring of CONFIG_VHOST. >>>>>>>>>>> >>>>>>>>>>> But this will leave a "CONFIG_VHOST_MENU=3Dy" in all defconfi= gs and even >>>>>>>>>>> for the ones that doesn't want vhost. So it actually shifts t= he >>>>>>>>>>> burdens to the maintainers of all other to add "CONFIG_VHOST_= MENU is >>>>>>>>>>> not set". So this patch tries to enable CONFIG_VHOST explicit= ly in >>>>>>>>>>> defconfigs that enables CONFIG_VHOST_NET and CONFIG_VHOST_VSO= CK. >>>>>>>>>>> >>>>>>>>>>> Acked-by: Christian Borntraeger (s= 390) >>>>>>>>>>> Acked-by: Michael Ellerman (powerpc) >>>>>>>>>>> Cc: Thomas Bogendoerfer >>>>>>>>>>> Cc: Benjamin Herrenschmidt >>>>>>>>>>> Cc: Paul Mackerras >>>>>>>>>>> Cc: Michael Ellerman >>>>>>>>>>> Cc: Heiko Carstens >>>>>>>>>>> Cc: Vasily Gorbik >>>>>>>>>>> Cc: Christian Borntraeger >>>>>>>>>>> Reported-by: Geert Uytterhoeven >>>>>>>>>>> Signed-off-by: Jason Wang >>>>>>>>>> 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=3Dy may end up with the similar sit= uation 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 j= ust >>>>>>>> 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=3Dy" w= ill be left >>>>>>> in the defconfigs. >>>>>> But who cares? >>>>> FYI, please seehttps://www.spinics.net/lists/kvm/msg212685.html >>>> The complaint was not about the symbol IIUC. It was that we caused >>>> everyone to build vhost unless they manually disabled it. >>> There could be some misunderstanding here. I thought it's somehow sim= ilar: a >>> CONFIG_VHOST_MENU=3Dy will be left in the defconfigs even if CONFIG_V= HOST is >>> not set. >>> >>> Thanks >> Hmm. So looking at Documentation/kbuild/kconfig-language.rst : >> >> Things that merit "default y/m" include: >> >> a) A new Kconfig option for something that used to always be = built >> should be "default y". >> >> b) A new gatekeeping Kconfig option that hides/shows other Kc= onfig >> options (but does not generate any code of its own), shoul= d be >> "default y" so people will see those other options. >> >> c) Sub-driver behavior or similar options for a driver that i= s >> "default n". This allows you to provide sane defaults. >> >> >> So it looks like VHOST_MENU is actually matching rule b). >> So what's the problem we are trying to solve with this patch, exactly? >> >> Geert could you clarify pls? > I can confirm VHOST_MENU is matching rule b), so it is safe to always > enable it. > > Gr{oetje,eeting}s, > > Geert Right, so I think we can drop this patch. Thanks