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, 5 insertions, 16 deletions

diff --git a/arch/powerpc/kvm/timing.c b/arch/powerpc/kvm/timing.c
index ba56a5cbba97..25071331f8c1 100644
--- a/arch/powerpc/kvm/timing.c
+++ b/arch/powerpc/kvm/timing.c
@@ -204,21 +204,10 @@ static const struct file_operations kvmppc_exit_timing_fops = {
 	.release = single_release,
 };
 
-void kvmppc_create_vcpu_debugfs(struct kvm_vcpu *vcpu, unsigned int id)
+int kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu,
+				    struct dentry *debugfs_dentry)
 {
-	static char dbg_fname[50];
-	struct dentry *debugfs_file;
-
-	snprintf(dbg_fname, sizeof(dbg_fname), "vm%u_vcpu%u_timing",
-		 current->pid, id);
-	debugfs_file = debugfs_create_file(dbg_fname, 0666, kvm_debugfs_dir,
-						vcpu, &kvmppc_exit_timing_fops);
-
-	vcpu->arch.debugfs_exit_timing = debugfs_file;
-}
-
-void kvmppc_remove_vcpu_debugfs(struct kvm_vcpu *vcpu)
-{
-	debugfs_remove(vcpu->arch.debugfs_exit_timing);
-	vcpu->arch.debugfs_exit_timing = NULL;
+	debugfs_create_file("timing", 0666, debugfs_dentry,
+			    vcpu, &kvmppc_exit_timing_fops);
+	return 0;
 }