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Reply-To: Gavin Shan <gshan@redhat.com>
Subject: Re: [PATCH] KVM: Fix a warning in __kvm_gfn_to_hva_cache_init()
To:     Peter Xu <peterx@redhat.com>, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org
Cc:     Paolo Bonzini <pbonzini@redhat.com>
References: <20200504190526.84456-1-peterx@redhat.com>
From:   Gavin Shan <gshan@redhat.com>
Message-ID: <871e801d-10dc-f1d5-a4a5-efc6824ebd21@redhat.com>
Date:   Tue, 5 May 2020 09:20:27 +1000
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On 5/5/20 5:05 AM, Peter Xu wrote:
> GCC 10.0.1 gives me this warning when building KVM:
>=20
>    warning: =E2=80=98nr_pages_avail=E2=80=99 may be used uninitialized =
in this function [-Wmaybe-uninitialized]
>    2442 |  for ( ; start_gfn <=3D end_gfn; start_gfn +=3D nr_pages_avai=
l) {
>=20
> It should not happen, but silent it.
>=20
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>   virt/kvm/kvm_main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>=20

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 74bdb7bf3295..2da293885a67 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2425,7 +2425,7 @@ static int __kvm_gfn_to_hva_cache_init(struct kvm=
_memslots *slots,
>   	gfn_t start_gfn =3D gpa >> PAGE_SHIFT;
>   	gfn_t end_gfn =3D (gpa + len - 1) >> PAGE_SHIFT;
>   	gfn_t nr_pages_needed =3D end_gfn - start_gfn + 1;
> -	gfn_t nr_pages_avail;
> +	gfn_t nr_pages_avail =3D 0;
>  =20
>   	/* Update ghc->generation before performing any error checks. */
>   	ghc->generation =3D slots->generation;
>=20