KVM: Teardown VFIO ops earlier in kvm_exit()

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().

That kvm_vfio_ops_exit() is called last appears to be 100% arbitrary.  It
was bolted on after the fact by commit 571ee1b68598 ("kvm: vfio: fix
unregister kvm_device_ops of vfio").  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.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Message-Id: <20221130230934.1014142-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6398358..7026437 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -6049,6 +6049,7 @@ void kvm_exit(void)
        for_each_possible_cpu(cpu)
                free_cpumask_var(per_cpu(cpu_kick_mask, cpu));
        kmem_cache_destroy(kvm_vcpu_cache);
+       kvm_vfio_ops_exit();
        kvm_async_pf_deinit();
        unregister_syscore_ops(&kvm_syscore_ops);
        unregister_reboot_notifier(&kvm_reboot_notifier);
@@ -6058,7 +6059,6 @@ void kvm_exit(void)
        free_cpumask_var(cpus_hardware_enabled);
        kvm_arch_hardware_unsetup();
        kvm_arch_exit();
-       kvm_vfio_ops_exit();
 }
 EXPORT_SYMBOL_GPL(kvm_exit);