KVM: Move wiping of the kvm->vcpus array to common code

All architectures have similar loops iterating over the vcpus,
freeing one vcpu at a time, and eventually wiping the reference
off the vcpus array. They are also inconsistently taking
the kvm->lock mutex when wiping the references from the array.

Make this code common, which will simplify further changes.
The locking is dropped altogether, as this should only be called
when there is no further references on the kvm structure.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211116160403.4074052-2-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e4727dc..362b10c 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -175,19 +175,11 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
  */
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
-       int i;
-
        bitmap_free(kvm->arch.pmu_filter);
 
        kvm_vgic_destroy(kvm);
 
-       for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-               if (kvm->vcpus[i]) {
-                       kvm_vcpu_destroy(kvm->vcpus[i]);
-                       kvm->vcpus[i] = NULL;
-               }
-       }
-       atomic_set(&kvm->online_vcpus, 0);
+       kvm_destroy_vcpus(kvm);
 }
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)

diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index aa20d07..6aa5e37 100644 (file)
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -171,25 +171,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
        return 0;
 }
 
-void kvm_mips_free_vcpus(struct kvm *kvm)
-{
-       unsigned int i;
-       struct kvm_vcpu *vcpu;
-
-       kvm_for_each_vcpu(i, vcpu, kvm) {
-               kvm_vcpu_destroy(vcpu);
-       }
-
-       mutex_lock(&kvm->lock);
-
-       for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
-               kvm->vcpus[i] = NULL;
-
-       atomic_set(&kvm->online_vcpus, 0);
-
-       mutex_unlock(&kvm->lock);
-}
-
 static void kvm_mips_free_gpa_pt(struct kvm *kvm)
 {
        /* It should always be safe to remove after flushing the whole range */
@@ -199,7 +180,7 @@ static void kvm_mips_free_gpa_pt(struct kvm *kvm)
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
-       kvm_mips_free_vcpus(kvm);
+       kvm_destroy_vcpus(kvm);
        kvm_mips_free_gpa_pt(kvm);
 }
 

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index a72920f..98f5d90 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -463,9 +463,6 @@ err_out:
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
-       unsigned int i;
-       struct kvm_vcpu *vcpu;
-
 #ifdef CONFIG_KVM_XICS
        /*
         * We call kick_all_cpus_sync() to ensure that all
@@ -476,14 +473,9 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
                kick_all_cpus_sync();
 #endif
 
-       kvm_for_each_vcpu(i, vcpu, kvm)
-               kvm_vcpu_destroy(vcpu);
+       kvm_destroy_vcpus(kvm);
 
        mutex_lock(&kvm->lock);
-       for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
-               kvm->vcpus[i] = NULL;
-
-       atomic_set(&kvm->online_vcpus, 0);
 
        kvmppc_core_destroy_vm(kvm);
 

diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
index fb18af3..7619691 100644 (file)
--- a/arch/riscv/kvm/vm.c
+++ b/arch/riscv/kvm/vm.c
@@ -46,15 +46,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
-       int i;
-
-       for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-               if (kvm->vcpus[i]) {
-                       kvm_vcpu_destroy(kvm->vcpus[i]);
-                       kvm->vcpus[i] = NULL;
-               }
-       }
-       atomic_set(&kvm->online_vcpus, 0);
+       kvm_destroy_vcpus(kvm);
 }
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 14a18ba..6eeb59a 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2821,27 +2821,11 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
        free_page((unsigned long)(vcpu->arch.sie_block));
 }
 
-static void kvm_free_vcpus(struct kvm *kvm)
-{
-       unsigned int i;
-       struct kvm_vcpu *vcpu;
-
-       kvm_for_each_vcpu(i, vcpu, kvm)
-               kvm_vcpu_destroy(vcpu);
-
-       mutex_lock(&kvm->lock);
-       for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
-               kvm->vcpus[i] = NULL;
-
-       atomic_set(&kvm->online_vcpus, 0);
-       mutex_unlock(&kvm->lock);
-}
-
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
        u16 rc, rrc;
 
-       kvm_free_vcpus(kvm);
+       kvm_destroy_vcpus(kvm);
        sca_dispose(kvm);
        kvm_s390_gisa_destroy(kvm);
        /*

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e0aa4dd..0e6d11a 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11423,15 +11423,8 @@ static void kvm_free_vcpus(struct kvm *kvm)
                kvm_clear_async_pf_completion_queue(vcpu);
                kvm_unload_vcpu_mmu(vcpu);
        }
-       kvm_for_each_vcpu(i, vcpu, kvm)
-               kvm_vcpu_destroy(vcpu);
-
-       mutex_lock(&kvm->lock);
-       for (i = 0; i < atomic_read(&kvm->online_vcpus); i++)
-               kvm->vcpus[i] = NULL;
 
-       atomic_set(&kvm->online_vcpus, 0);
-       mutex_unlock(&kvm->lock);
+       kvm_destroy_vcpus(kvm);
 }
 
 void kvm_arch_sync_events(struct kvm *kvm)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c310648..e2f9f8f 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -733,7 +733,7 @@ static inline struct kvm_vcpu *kvm_get_vcpu_by_id(struct kvm *kvm, int id)
                if (WARN_ON_ONCE(!memslot->npages)) {                   \
                } else
 
-void kvm_vcpu_destroy(struct kvm_vcpu *vcpu);
+void kvm_destroy_vcpus(struct kvm *kvm);
 
 void vcpu_load(struct kvm_vcpu *vcpu);
 void vcpu_put(struct kvm_vcpu *vcpu);

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 72c4e6b..0a504c7 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -435,7 +435,7 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
        vcpu->last_used_slot = 0;
 }
 
-void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
+static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
        kvm_dirty_ring_free(&vcpu->dirty_ring);
        kvm_arch_vcpu_destroy(vcpu);
@@ -450,7 +450,20 @@ void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
        free_page((unsigned long)vcpu->run);
        kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
-EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
+
+void kvm_destroy_vcpus(struct kvm *kvm)
+{
+       unsigned int i;
+       struct kvm_vcpu *vcpu;
+
+       kvm_for_each_vcpu(i, vcpu, kvm) {
+               kvm_vcpu_destroy(vcpu);
+               kvm->vcpus[i] = NULL;
+       }
+
+       atomic_set(&kvm->online_vcpus, 0);
+}
+EXPORT_SYMBOL_GPL(kvm_destroy_vcpus);
 
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
 static inline struct kvm *mmu_notifier_to_kvm(struct mmu_notifier *mn)