Commit c560bc92 authored by Maxim Levitsky's avatar Maxim Levitsky Committed by Paolo Bonzini
Browse files

x86: KVM: SVM: use kvm_lock_all_vcpus instead of a custom implementation 



Use kvm_lock_all_vcpus instead of sev's own implementation.

Because kvm_lock_all_vcpus uses the _nest_lock feature of lockdep, which
ignores subclasses, there is no longer a need to use separate subclasses
for source and target VMs.

No functional change intended.

Suggested-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Message-ID: <20250512180407.659015-5-mlevitsk@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e4a454ce

arch/x86/kvm/svm/sev.c

+4 −68
Original line number Diff line number Diff line
@@ -1882,70 +1882,6 @@ static void sev_unlock_two_vms(struct kvm *dst_kvm, struct kvm *src_kvm) 
	atomic_set_release(&src_sev->migration_in_progress, 0);

}



/* vCPU mutex subclasses.  */

enum sev_migration_role {

	SEV_MIGRATION_SOURCE = 0,

	SEV_MIGRATION_TARGET,

	SEV_NR_MIGRATION_ROLES,

};



static int sev_lock_vcpus_for_migration(struct kvm *kvm,

					enum sev_migration_role role)

{

	struct kvm_vcpu *vcpu;

	unsigned long i, j;



	kvm_for_each_vcpu(i, vcpu, kvm) {

		if (mutex_lock_killable_nested(&vcpu->mutex, role))

			goto out_unlock;



#ifdef CONFIG_PROVE_LOCKING

		if (!i)

			/*

			 * Reset the role to one that avoids colliding with

			 * the role used for the first vcpu mutex.

			 */

			role = SEV_NR_MIGRATION_ROLES;

		else

			mutex_release(&vcpu->mutex.dep_map, _THIS_IP_);

#endif

	}



	return 0;



out_unlock:



	kvm_for_each_vcpu(j, vcpu, kvm) {

		if (i == j)

			break;



#ifdef CONFIG_PROVE_LOCKING

		if (j)

			mutex_acquire(&vcpu->mutex.dep_map, role, 0, _THIS_IP_);

#endif



		mutex_unlock(&vcpu->mutex);

	}

	return -EINTR;

}



static void sev_unlock_vcpus_for_migration(struct kvm *kvm)

{

	struct kvm_vcpu *vcpu;

	unsigned long i;

	bool first = true;



	kvm_for_each_vcpu(i, vcpu, kvm) {

		if (first)

			first = false;

		else

			mutex_acquire(&vcpu->mutex.dep_map,

				      SEV_NR_MIGRATION_ROLES, 0, _THIS_IP_);



		mutex_unlock(&vcpu->mutex);

	}

}



static void sev_migrate_from(struct kvm *dst_kvm, struct kvm *src_kvm)

{

	struct kvm_sev_info *dst = to_kvm_sev_info(dst_kvm);
@@ -2083,10 +2019,10 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) 
		charged = true;

	}



	ret = sev_lock_vcpus_for_migration(kvm, SEV_MIGRATION_SOURCE);

	ret = kvm_lock_all_vcpus(kvm);

	if (ret)

		goto out_dst_cgroup;

	ret = sev_lock_vcpus_for_migration(source_kvm, SEV_MIGRATION_TARGET);

	ret = kvm_lock_all_vcpus(source_kvm);

	if (ret)

		goto out_dst_vcpu;
@@ -2100,9 +2036,9 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd) 
	ret = 0;



out_source_vcpu:

	sev_unlock_vcpus_for_migration(source_kvm);

	kvm_unlock_all_vcpus(source_kvm);

out_dst_vcpu:

	sev_unlock_vcpus_for_migration(kvm);

	kvm_unlock_all_vcpus(kvm);

out_dst_cgroup:

	/* Operates on the source on success, on the destination on failure.  */

	if (charged)