KVM: x86/mmu: Use KVM_PAGES_PER_HPAGE() instead of an open coded equivalent

Use KVM_PAGES_PER_HPAGE() instead of open coding equivalent logic that is
anything but obvious.

No functional change intended, and verified by compiling with the below
assertions:

        BUILD_BUG_ON((1UL << KVM_HPAGE_GFN_SHIFT(PG_LEVEL_4K)) !=
                      KVM_PAGES_PER_HPAGE(PG_LEVEL_4K));

        BUILD_BUG_ON((1UL << KVM_HPAGE_GFN_SHIFT(PG_LEVEL_2M)) !=
                      KVM_PAGES_PER_HPAGE(PG_LEVEL_2M));

        BUILD_BUG_ON((1UL << KVM_HPAGE_GFN_SHIFT(PG_LEVEL_1G)) !=
                      KVM_PAGES_PER_HPAGE(PG_LEVEL_1G));

Link: https://lore.kernel.org/r/20240809194335.1726916-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 53e24892055adb770d903e831cb380a9a231b543..b751e7e2a05e4f88bce3ecdf469d105cafe002aa 100644 (file)
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1464,7 +1464,7 @@ static bool slot_rmap_walk_okay(struct slot_rmap_walk_iterator *iterator)
 static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
 {
        while (++iterator->rmap <= iterator->end_rmap) {
-               iterator->gfn += (1UL << KVM_HPAGE_GFN_SHIFT(iterator->level));
+               iterator->gfn += KVM_PAGES_PER_HPAGE(iterator->level);
 
                if (iterator->rmap->val)
                        return;