[PATCH] KVM: PPC: BOOK3S: book3s_hv_nested.c: improve branch prediction for k.alloc

[Kautuk Consul]

I used the unlikely() macro on the return values of the k.alloc
calls and found that it changes the code generation a bit.
Optimize all return paths of k.alloc calls by improving
branch prediction on return value of k.alloc.

Signed-off-by: Kautuk Consul <kcon...@linux.vnet.ibm.com>
---
 arch/powerpc/kvm/book3s_hv_nested.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c 
b/arch/powerpc/kvm/book3s_hv_nested.c
index 5a64a1341e6f..dbf2dd073e1f 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -446,7 +446,7 @@ long kvmhv_nested_init(void)
                ptb_order = 12;
        pseries_partition_tb = kmalloc(sizeof(struct patb_entry) << ptb_order,
                                       GFP_KERNEL);
-       if (!pseries_partition_tb) {
+       if (unlikely(!pseries_partition_tb)) {
                pr_err("kvm-hv: failed to allocated nested partition table\n");
                return -ENOMEM;
        }
@@ -575,7 +575,7 @@ long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu)
                return H_PARAMETER;
 
        buf = kzalloc(n, GFP_KERNEL | __GFP_NOWARN);
-       if (!buf)
+       if (unlikely(!buf))
                return H_NO_MEM;
 
        gp = kvmhv_get_nested(vcpu->kvm, l1_lpid, false);
@@ -689,7 +689,7 @@ static struct kvm_nested_guest *kvmhv_alloc_nested(struct 
kvm *kvm, unsigned int
        long shadow_lpid;
 
        gp = kzalloc(sizeof(*gp), GFP_KERNEL);
-       if (!gp)
+       if (unlikely(!gp))
                return NULL;
        gp->l1_host = kvm;
        gp->l1_lpid = lpid;
@@ -1633,7 +1633,7 @@ static long int __kvmhv_nested_page_fault(struct kvm_vcpu 
*vcpu,
        /* 4. Insert the pte into our shadow_pgtable */
 
        n_rmap = kzalloc(sizeof(*n_rmap), GFP_KERNEL);
-       if (!n_rmap)
+       if (unlikely(!n_rmap))
                return RESUME_GUEST; /* Let the guest try again */
        n_rmap->rmap = (n_gpa & RMAP_NESTED_GPA_MASK) |
                (((unsigned long) gp->l1_lpid) << RMAP_NESTED_LPID_SHIFT);
-- 
2.39.2