KVM: x86: remove check on nr_mmu_pages in kvm_arch_commit_memory_region()

* nr_mmu_pages would be non-zero only if kvm->arch.n_requested_mmu_pages is
  non-zero.

* nr_mmu_pages is always non-zero, since kvm_mmu_calculate_mmu_pages()
  never return zero.

Based on these two reasons, we can merge the two *if* clause and use the
return value from kvm_mmu_calculate_mmu_pages() directly. This simplify
the code and also eliminate the possibility for reader to believe
nr_mmu_pages would be zero.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 4 insertions, 8 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5b03006c00be..679168931c40 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1254,7 +1254,7 @@ void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm,
                                    gfn_t gfn_offset, unsigned long mask);
 void kvm_mmu_zap_all(struct kvm *kvm);
 void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen);
-unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm);
+unsigned int kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm);
 void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages);
 
 int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index f6d760dcdb75..5a9981465fbb 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -6028,7 +6028,7 @@ out:
 /*
  * Calculate mmu pages needed for kvm.
  */
-unsigned int kvm_mmu_calculate_mmu_pages(struct kvm *kvm)
+unsigned int kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm)
 {
         unsigned int nr_mmu_pages;
         unsigned int  nr_pages = 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 65e4559eef2f..491e92383da8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9429,13 +9429,9 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
                                 const struct kvm_memory_slot *new,
                                 enum kvm_mr_change change)
 {
-        int nr_mmu_pages = 0;
-
         if (!kvm->arch.n_requested_mmu_pages)
-                nr_mmu_pages = kvm_mmu_calculate_mmu_pages(kvm);
-
-        if (nr_mmu_pages)
-                kvm_mmu_change_mmu_pages(kvm, nr_mmu_pages);
+                kvm_mmu_change_mmu_pages(kvm,
+                                kvm_mmu_calculate_default_mmu_pages(kvm));
 
         /*
          * Dirty logging tracks sptes in 4k granularity, meaning that large