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Date:   Wed, 12 May 2021 18:02:37 +0100
Message-ID: <87h7j7opg2.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Alexandru Elisei <alexandru.elisei@arm.com>
Cc:     Naresh Kamboju <naresh.kamboju@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        Florian Fainelli <f.fainelli@gmail.com>, patches@kernelci.org,
        lkft-triage@lists.linaro.org, Jon Hunter <jonathanh@nvidia.com>,
        linux-stable <stable@vger.kernel.org>,
        Pavel Machek <pavel@denx.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH 5.4 000/244] 5.4.119-rc1 review
In-Reply-To: <b7df0d7f-e582-6a0d-2385-b9fce50f9106@arm.com>
References: <20210512144743.039977287@linuxfoundation.org>
        <CA+G9fYs1AH8ZNWMJ=H4TY5C6bqp--=SZfW9P=WbB85qSBDkuXw@mail.gmail.com>
        <b7df0d7f-e582-6a0d-2385-b9fce50f9106@arm.com>
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On Wed, 12 May 2021 18:00:16 +0100,
Alexandru Elisei <alexandru.elisei@arm.com> wrote:
> 
> Hi Naresh,
> 
> Thank you for the report!
> 
> On 5/12/21 5:47 PM, Naresh Kamboju wrote:
> > On Wed, 12 May 2021 at 20:22, Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> >> This is the start of the stable review cycle for the 5.4.119 release.
> >> There are 244 patches in this series, all will be posted as a response
> >> to this one.  If anyone has any issues with these being applied, please
> >> let me know.
> >>
> >> Responses should be made by Fri, 14 May 2021 14:47:09 +0000.
> >> Anything received after that time might be too late.
> >>
> >> The whole patch series can be found in one patch at:
> >>         https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.4.119-rc1.gz
> >> or in the git tree and branch at:
> >>         git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y
> >> and the diffstat can be found below.
> >>
> >> thanks,
> >>
> >> greg k-h
> > Build regression detected.
> >
> >> Alexandru Elisei <alexandru.elisei@arm.com>
> >>     KVM: arm64: Initialize VCPU mdcr_el2 before loading it
> > stable rc 5.4 arm axm55xx_defconfig builds failed due to these
> > warnings / errors.
> >   - arm (axm55xx_defconfig) with gcc-8,9 and 10 failed
> >
> > arch/arm/kvm/../../../virt/kvm/arm/arm.c: In function 'kvm_vcpu_first_run_init':
> > arch/arm/kvm/../../../virt/kvm/arm/arm.c:582:2: error: implicit
> > declaration of function 'kvm_arm_vcpu_init_debug'; did you mean
> > 'kvm_arm_init_debug'? [-Werror=implicit-function-declaration]
> >   kvm_arm_vcpu_init_debug(vcpu);
> >   ^~~~~~~~~~~~~~~~~~~~~~~
> >   kvm_arm_init_debug
> > cc1: some warnings being treated as errors
> 
> This is my fault, in Linux v5.4 KVM for arm is still around, and
> there's no prototype for the function when compiling for arm. I
> suspect that's also the case for v4.19.
> 
> I made this change to get it to build:
> 
> $ git diff
> diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> index dd03d5e01a94..32564b017ba0 100644
> --- a/arch/arm/include/asm/kvm_host.h
> +++ b/arch/arm/include/asm/kvm_host.h
> @@ -335,6 +335,7 @@ static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu,
> int cpu) {}
>  static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
>  
>  static inline void kvm_arm_init_debug(void) {}
> +static inline void kvm_arm_vcpu_init_debug(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arm_clear_debug(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) {}
> 
> which matches the stub for kvm_arm_init_debug(). I can spin a patch
> out of it and send it for 5.4 and 4.19. Marc, what do you think?

Ideally, we'd drop the patch in its current form from 5.4 and 4.19,
and send an updated patch with this hunk to fix the 32bit build.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.