KVM: PPC: Merge powerpc's debugfs entry content into generic entry

At the moment KVM on PPC creates 4 types of entries under the kvm debugfs:
1) "%pid-%fd" per a KVM instance (for all platforms);
2) "vm%pid" (for PPC Book3s HV KVM);
3) "vm%u_vcpu%u_timing" (for PPC Book3e KVM);
4) "kvm-xive-%p" (for XIVE PPC Book3s KVM, the same for XICS);

The problem with this is that multiple VMs per process is not allowed for
2) and 3) which makes it possible for userspace to trigger errors when
creating duplicated debugfs entries.

This merges all these into 1).

This defines kvm_arch_create_kvm_debugfs() similar to
kvm_arch_create_vcpu_debugfs().

This defines 2 hooks in kvmppc_ops that allow specific KVM implementations
add necessary entries, this adds the _e500 suffix to
kvmppc_create_vcpu_debugfs_e500() to make it clear what platform it is for.

This makes use of already existing kvm_arch_create_vcpu_debugfs() on PPC.

This removes no more used debugfs_dir pointers from PPC kvm_arch structs.

This stops removing vcpu entries as once created vcpus stay around
for the entire life of a VM and removed when the KVM instance is closed,
see commit d56f5136b010 ("KVM: let kvm_destroy_vm_debugfs clean up vCPU
debugfs directories").

Suggested-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220111005404.162219-1-aik@ozlabs.ru

1 files changed, 13 insertions, 3 deletions

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 82d889db2b6b..1d06b68739b0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -777,7 +777,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 	rcuwait_init(&vcpu->arch.wait);
 	vcpu->arch.waitp = &vcpu->arch.wait;
-	kvmppc_create_vcpu_debugfs(vcpu, vcpu->vcpu_id);
 	return 0;
 
 out_vcpu_uninit:
@@ -794,8 +793,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 	/* Make sure we're not using the vcpu anymore */
 	hrtimer_cancel(&vcpu->arch.dec_timer);
 
-	kvmppc_remove_vcpu_debugfs(vcpu);
-
 	switch (vcpu->arch.irq_type) {
 	case KVMPPC_IRQ_MPIC:
 		kvmppc_mpic_disconnect_vcpu(vcpu->arch.mpic, vcpu);
@@ -2521,3 +2518,16 @@ int kvm_arch_init(void *opaque)
 }
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_ppc_instr);
+
+void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry)
+{
+	if (vcpu->kvm->arch.kvm_ops->create_vcpu_debugfs)
+		vcpu->kvm->arch.kvm_ops->create_vcpu_debugfs(vcpu, debugfs_dentry);
+}
+
+int 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;
+}