On 12/17/21 04:07, Alexey Kardashevskiy wrote:
On 12/16/21 05:11, Cédric Le Goater wrote:
On 12/15/21 02:33, Alexey Kardashevskiy wrote:
At the moment KVM on PPC creates 3 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).
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").
It would nice to also move the KVM device debugfs files :
/sys/kernel/debug/powerpc/kvm-xive-%p
These are dynamically created and destroyed at run time depending
on the interrupt mode negociated by CAS. It might be more complex ?
With this addition:
diff --git a/arch/powerpc/kvm/book3s_xive_native.c
b/arch/powerpc/kvm/book3s_xive_native.c
index 99db9ac49901..511f643e2875 100644
--- a/arch/powerpc/kvm/book3s_xive_native.c
+++ b/arch/powerpc/kvm/book3s_xive_native.c
@@ -1267,10 +1267,10 @@ static void xive_native_debugfs_init(struct
kvmppc_xive *xive)
return;
}
- xive->dentry = debugfs_create_file(name, 0444, arch_debugfs_dir,
+ xive->dentry = debugfs_create_file(name, 0444,
xive->kvm->debugfs_dentry,
xive, &xive_native_debug_fops);
it looks fine, this is "before":
root@zz1:/sys/kernel/debug# find -iname "*xive*"
./slab/xive-provision
./powerpc/kvm-xive-c0000000208c0000
./powerpc/xive
and this is "after" the patch applied.
root@zz1:/sys/kernel/debug# find -iname "*xive*"
./kvm/29058-11/kvm-xive-c0000000208c0000
./slab/xive-provision
./powerpc/xive
I think "./kvm/29058-11/xive" should be enough now. The KVM prefix is
redundant and so is the %p which was used to distinguish VMs.
The same change could be done for the KVM XICS device.
Thanks,
C.
