[PATCH 1/5] KVM: Move wiping of the kvm->vcpus array to common code
Claudio Imbrenda
imbrenda at linux.ibm.com
Mon Nov 8 23:12:02 AEDT 2021
On Fri, 5 Nov 2021 19:20:57 +0000
Marc Zyngier <maz at kernel.org> wrote:
> 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.
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>
no objections
Reviewed-by: Claudio Imbrenda <imbrenda at linux.ibm.com>
> ---
> arch/arm64/kvm/arm.c | 10 +---------
> arch/mips/kvm/mips.c | 21 +--------------------
> arch/powerpc/kvm/powerpc.c | 10 +---------
> arch/riscv/kvm/vm.c | 10 +---------
> arch/s390/kvm/kvm-s390.c | 18 +-----------------
> arch/x86/kvm/x86.c | 9 +--------
> include/linux/kvm_host.h | 2 +-
> virt/kvm/kvm_main.c | 20 ++++++++++++++++++--
> 8 files changed, 25 insertions(+), 75 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index f5490afe1ebf..75bb7215da03 100644
> --- 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 562aa878b266..ceacca74f808 100644
> --- 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 35e9cccdeef9..492e4a4121cb 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -463,9 +463,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
>
> 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 26399df15b63..6af6cde295eb 100644
> --- 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 c6257f625929..7af53b8788fa 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2819,27 +2819,11 @@ 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 c1c4e2b05a63..498a43126615 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11302,15 +11302,8 @@ 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 60a35d9fe259..36967291b8c6 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -725,7 +725,7 @@ 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 3f6d450355f0..d83553eeea21 100644
> --- 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 +450,23 @@ 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);
> +
> + 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);
> +}
> +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)
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