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Message-ID: <1386ccd1ff60cb8e4af80fbb294160a8d7cc3b5b.camel@linux.ibm.com>
Subject: Re: [PATCH 05/44] KVM: s390: Unwind kvm_arch_init()
 piece-by-piece() if a step fails
From:   Eric Farman <farman@linux.ibm.com>
To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        Huacai Chen <chenhuacai@kernel.org>,
        Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>,
        Anup Patel <anup@brainfault.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Janosch Frank <frankja@linux.ibm.com>,
        Claudio Imbrenda <imbrenda@linux.ibm.com>,
        Matthew Rosato <mjrosato@linux.ibm.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>
Cc:     James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Oliver Upton <oliver.upton@linux.dev>,
        Atish Patra <atishp@atishpatra.org>,
        David Hildenbrand <david@redhat.com>, kvm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
        kvmarm@lists.cs.columbia.edu, linux-mips@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org, kvm-riscv@lists.infradead.org,
        linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Isaku Yamahata <isaku.yamahata@intel.com>,
        Fabiano Rosas <farosas@linux.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Chao Gao <chao.gao@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Yuan Yao <yuan.yao@intel.com>
Date:   Mon, 07 Nov 2022 12:57:17 -0500
In-Reply-To: <20221102231911.3107438-6-seanjc@google.com>
References: <20221102231911.3107438-1-seanjc@google.com>
         <20221102231911.3107438-6-seanjc@google.com>
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On Wed, 2022-11-02 at 23:18 +0000, Sean Christopherson wrote:
> In preparation for folding kvm_arch_hardware_setup() into
> kvm_arch_init(),
> unwind initialization one step at a time instead of simply calling
> kvm_arch_exit().=C2=A0 Using kvm_arch_exit() regardless of which
> initialization
> step failed relies on all affected state playing nice with being
> undone
> even if said state wasn't first setup.=C2=A0 That holds true for state
> that is
> currently configured by kvm_arch_init(), but not for state that's
> handled
> by kvm_arch_hardware_setup(), e.g. calling
> gmap_unregister_pte_notifier()
> without first registering a notifier would result in list corruption
> due
> to attempting to delete an entry that was never added to the list.
>=20
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> =C2=A0arch/s390/kvm/kvm-s390.c | 21 ++++++++++++++-------
> =C2=A01 file changed, 14 insertions(+), 7 deletions(-)

Reviewed-by: Eric Farman <farman@linux.ibm.com>