Commit fd217326 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Fold guts of kvm_arch_sync_events() into kvm_arch_pre_destroy_vm() 



Fold the guts of kvm_arch_sync_events() into kvm_arch_pre_destroy_vm(), as
the kvmclock and PIT background workers only need to be stopped before
destroying vCPUs (to avoid accessing vCPUs as they are being freed); it's
a-ok for them to be running while the VM is visible on the global vm_list.

Note, the PIT also needs to be stopped before IRQ routing is freed
(because KVM's IRQ routing is garbage and assumes there is always non-NULL
routing).

Opportunistically add comments to explain why KVM stops/frees certain
assets early.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Message-ID: <20250224235542.2562848-7-seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e4472125

arch/x86/kvm/x86.c

+12 −3
Original line number Diff line number Diff line
@@ -12759,9 +12759,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) 


void kvm_arch_sync_events(struct kvm *kvm)

{

	cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work);

	cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work);

	kvm_free_pit(kvm);



}



/**
@@ -12842,6 +12840,17 @@ EXPORT_SYMBOL_GPL(__x86_set_memory_region); 


void kvm_arch_pre_destroy_vm(struct kvm *kvm)

{

	/*

	 * Stop all background workers and kthreads before destroying vCPUs, as

	 * iterating over vCPUs in a different task while vCPUs are being freed

	 * is unsafe, i.e. will lead to use-after-free.  The PIT also needs to

	 * be stopped before IRQ routing is freed.

	 */

	cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work);

	cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work);



	kvm_free_pit(kvm);



	kvm_mmu_pre_destroy_vm(kvm);

}