| Message ID | 20240216155941.2029458-1-oliver.upton@linux.dev (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Get rid of return value from kvm_arch_create_vm_debugfs() | expand |
On Fri, 16 Feb 2024 15:59:41 +0000, Oliver Upton <oliver.upton@linux.dev> wrote: > > The general expectation with debugfs is that any initialization failure > is nonfatal. Nevertheless, kvm_arch_create_vm_debugfs() allows > implementations to return an error and kvm_create_vm_debugfs() allows > that to fail VM creation. > > Change to a void return to discourage architectures from making debugfs > failures fatal for the VM. Seems like everyone already had the right > idea, as all implementations already return 0 unconditionally. > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Acked-by: Marc Zyngier <maz@kernel.org> M.
On Fri, Feb 16, 2024 at 5:00 PM Oliver Upton <oliver.upton@linux.dev> wrote: > > The general expectation with debugfs is that any initialization failure > is nonfatal. Nevertheless, kvm_arch_create_vm_debugfs() allows > implementations to return an error and kvm_create_vm_debugfs() allows > that to fail VM creation. > > Change to a void return to discourage architectures from making debugfs > failures fatal for the VM. Seems like everyone already had the right > idea, as all implementations already return 0 unconditionally. > > Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Feel free to place it in kvm-arm. Paolo
On Fri, 16 Feb 2024 15:59:41 +0000, Oliver Upton wrote: > The general expectation with debugfs is that any initialization failure > is nonfatal. Nevertheless, kvm_arch_create_vm_debugfs() allows > implementations to return an error and kvm_create_vm_debugfs() allows > that to fail VM creation. > > Change to a void return to discourage architectures from making debugfs > failures fatal for the VM. Seems like everyone already had the right > idea, as all implementations already return 0 unconditionally. > > [...] Applied to kvmarm/next, thanks! [1/1] KVM: Get rid of return value from kvm_arch_create_vm_debugfs() https://git.kernel.org/kvmarm/kvmarm/c/284851ee5cae -- Best, Oliver
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 23407fbd73c9..d32abe7fe6ab 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -2538,9 +2538,8 @@ void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_ vcpu->kvm->arch.kvm_ops->create_vcpu_debugfs(vcpu, debugfs_dentry); } -int kvm_arch_create_vm_debugfs(struct kvm *kvm) +void kvm_arch_create_vm_debugfs(struct kvm *kvm) { if (kvm->arch.kvm_ops->create_vm_debugfs) kvm->arch.kvm_ops->create_vm_debugfs(kvm); - return 0; } diff --git a/arch/x86/kvm/debugfs.c b/arch/x86/kvm/debugfs.c index 95ea1a1f7403..999227fc7c66 100644 --- a/arch/x86/kvm/debugfs.c +++ b/arch/x86/kvm/debugfs.c @@ -189,9 +189,8 @@ static const struct file_operations mmu_rmaps_stat_fops = { .release = kvm_mmu_rmaps_stat_release, }; -int kvm_arch_create_vm_debugfs(struct kvm *kvm) +void kvm_arch_create_vm_debugfs(struct kvm *kvm) { debugfs_create_file("mmu_rmaps_stat", 0644, kvm->debugfs_dentry, kvm, &mmu_rmaps_stat_fops); - return 0; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 7e7fd25b09b3..9a45f673f687 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -1507,7 +1507,7 @@ bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu); bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu); int kvm_arch_post_init_vm(struct kvm *kvm); void kvm_arch_pre_destroy_vm(struct kvm *kvm); -int kvm_arch_create_vm_debugfs(struct kvm *kvm); +void kvm_arch_create_vm_debugfs(struct kvm *kvm); #ifndef __KVM_HAVE_ARCH_VM_ALLOC /* diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 10bfc88a69f7..c681149c382a 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1150,10 +1150,7 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, const char *fdname) &stat_fops_per_vm); } - ret = kvm_arch_create_vm_debugfs(kvm); - if (ret) - goto out_err; - + kvm_arch_create_vm_debugfs(kvm); return 0; out_err: kvm_destroy_vm_debugfs(kvm); @@ -1183,9 +1180,8 @@ void __weak kvm_arch_pre_destroy_vm(struct kvm *kvm) * Cleanup should be automatic done in kvm_destroy_vm_debugfs() recursively, so * a per-arch destroy interface is not needed. */ -int __weak kvm_arch_create_vm_debugfs(struct kvm *kvm) +void __weak kvm_arch_create_vm_debugfs(struct kvm *kvm) { - return 0; } static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
The general expectation with debugfs is that any initialization failure is nonfatal. Nevertheless, kvm_arch_create_vm_debugfs() allows implementations to return an error and kvm_create_vm_debugfs() allows that to fail VM creation. Change to a void return to discourage architectures from making debugfs failures fatal for the VM. Seems like everyone already had the right idea, as all implementations already return 0 unconditionally. Signed-off-by: Oliver Upton <oliver.upton@linux.dev> --- Compile-tested on arm64, powerpc, and x86 since I don't trust myself to even get this simple patch right. arch/powerpc/kvm/powerpc.c | 3 +-- arch/x86/kvm/debugfs.c | 3 +-- include/linux/kvm_host.h | 2 +- virt/kvm/kvm_main.c | 8 ++------ 4 files changed, 5 insertions(+), 11 deletions(-) base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d