KVM: PPC: Book3S HV: Use IDA allocator for LPID allocator

This removes the fixed-size lpid_inuse array.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220123120043.3586018-4-npiggin@gmail.com

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 1a0e3ede891fe2463cd8466738c32a17f0a61154..32561192cf121ae5b18f1dd661b364cd059ae9fe 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2496,20 +2496,22 @@ out:
        return r;
 }
 
-static unsigned long lpid_inuse[BITS_TO_LONGS(KVMPPC_NR_LPIDS)];
+static DEFINE_IDA(lpid_inuse);
 static unsigned long nr_lpids;
 
 long kvmppc_alloc_lpid(void)
 {
-       long lpid;
+       int lpid;
 
-       do {
-               lpid = find_first_zero_bit(lpid_inuse, KVMPPC_NR_LPIDS);
-               if (lpid >= nr_lpids) {
+       /* The host LPID must always be 0 (allocation starts at 1) */
+       lpid = ida_alloc_range(&lpid_inuse, 1, nr_lpids - 1, GFP_KERNEL);
+       if (lpid < 0) {
+               if (lpid == -ENOMEM)
+                       pr_err("%s: Out of memory\n", __func__);
+               else
                        pr_err("%s: No LPIDs free\n", __func__);
-                       return -ENOMEM;
-               }
-       } while (test_and_set_bit(lpid, lpid_inuse));
+               return -ENOMEM;
+       }
 
        return lpid;
 }
@@ -2517,15 +2519,14 @@ EXPORT_SYMBOL_GPL(kvmppc_alloc_lpid);
 
 void kvmppc_free_lpid(long lpid)
 {
-       clear_bit(lpid, lpid_inuse);
+       ida_free(&lpid_inuse, lpid);
 }
 EXPORT_SYMBOL_GPL(kvmppc_free_lpid);
 
+/* nr_lpids_param includes the host LPID */
 void kvmppc_init_lpid(unsigned long nr_lpids_param)
 {
-       nr_lpids = min_t(unsigned long, KVMPPC_NR_LPIDS, nr_lpids_param);
-       memset(lpid_inuse, 0, sizeof(lpid_inuse));
-       set_bit(0, lpid_inuse); /* The host LPID must always be 0 */
+       nr_lpids = nr_lpids_param;
 }
 EXPORT_SYMBOL_GPL(kvmppc_init_lpid);