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Message-ID: <5e44854b2781a0be6fae5c82645ac64ef9b5dccf.camel@linux.ibm.com>
Subject: Re: [PATCH 04/44] KVM: Teardown VFIO ops earlier in kvm_exit()
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 12:56:51 -0500
In-Reply-To: <20221102231911.3107438-5-seanjc@google.com>
References: <20221102231911.3107438-1-seanjc@google.com>
         <20221102231911.3107438-5-seanjc@google.com>
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On Wed, 2022-11-02 at 23:18 +0000, Sean Christopherson wrote:
> Move the call to kvm_vfio_ops_exit() further up kvm_exit() to try and
> bring some amount of symmetry to the setup order in kvm_init(), and
> more
> importantly so that the arch hooks are invoked dead last by
> kvm_exit().
> This will allow arch code to move away from the arch hooks without
> any
> change in ordering between arch code and common code in kvm_exit().
>=20
> That kvm_vfio_ops_exit() is called last appears to be 100%
> arbitrary.=C2=A0 It
> was bolted on after the fact by commit 571ee1b68598 ("kvm: vfio: fix
> unregister kvm_device_ops of vfio").=C2=A0 The nullified
> kvm_device_ops_table
> is also local to kvm_main.c and is used only when there are active
> VMs,
> so unless arch code is doing something truly bizarre, nullifying the
> table earlier in kvm_exit() is little more than a nop.
>=20
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> =C2=A0virt/kvm/kvm_main.c | 2 +-
> =C2=A01 file changed, 1 insertion(+), 1 deletion(-)

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