[PATCH 44/45] KVM: Move putting of vcpu->pid to kvm_vcpu_destroy()

Sean Christopherson
2019-10-22T01:59:24Z

Move the putting of vcpu->pid to kvm_vcpu_destroy(). vcpu->pid is
guaranteed to be NULL when kvm_vcpu_uninit() is called in the error
path of kvm_vm_ioctl_create_vcpu(), e.g. it is explicit nullified by
kvm_vcpu_init() and is only changed by KVM_RUN.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
virt/kvm/kvm_main.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index b1f4ee9c2c76..c079b22032fa 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -318,12 +318,6 @@ static int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)

static void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
{
- /*
- * no need for rcu_read_lock as VCPU_RUN is the only place that
- * will change the vcpu->pid pointer and on uninit all file
- * descriptors are already gone.
- */
- put_pid(rcu_dereference_protected(vcpu->pid, 1));
free_page((unsigned long)vcpu->run);
}

@@ -331,6 +325,13 @@ void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
{
kvm_arch_vcpu_destroy(vcpu);

+ /*
+ * No need for rcu_read_lock as VCPU_RUN is the only place that changes
+ * the vcpu->pid pointer, and at destruction time all file descriptors
+ * are already gone.
+ */
+ put_pid(rcu_dereference_protected(vcpu->pid, 1));
+
kvm_vcpu_uninit(vcpu);
kmem_cache_free(kvm_vcpu_cache, vcpu);
}
--
2.22.0