KVM: x86/mmu: Hard code GFP flags for TDP MMU eager split allocations

Now that the GFP_NOWAIT case is gone, hard code GFP_KERNEL_ACCOUNT when
allocating shadow pages during eager page splitting in the TDP MMU.
Opportunistically replace use of __GFP_ZERO with allocations that zero
to improve readability.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20240611220512.2426439-3-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: dmatlack

arch/x86/kvm/mmu/tdp_mmu.c

@@ -1339,17 +1339,15 @@ bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm,
 	return spte_set;
 }
 
-static struct kvm_mmu_page *__tdp_mmu_alloc_sp_for_split(gfp_t gfp)
+static struct kvm_mmu_page *__tdp_mmu_alloc_sp_for_split(void)
 {
 	struct kvm_mmu_page *sp;
 
-	gfp |= __GFP_ZERO;
-
-	sp = kmem_cache_alloc(mmu_page_header_cache, gfp);
+	sp = kmem_cache_zalloc(mmu_page_header_cache, GFP_KERNEL_ACCOUNT);
 	if (!sp)
 		return NULL;
 
-	sp->spt = (void *)__get_free_page(gfp);
+	sp->spt = (void *)get_zeroed_page(GFP_KERNEL_ACCOUNT);
 	if (!sp->spt) {
 		kmem_cache_free(mmu_page_header_cache, sp);
 		return NULL;
@@ -1374,7 +1372,7 @@ static struct kvm_mmu_page *tdp_mmu_alloc_sp_for_split(struct kvm *kvm,
 		write_unlock(&kvm->mmu_lock);
 
 	iter->yielded = true;
-	sp = __tdp_mmu_alloc_sp_for_split(GFP_KERNEL_ACCOUNT);
+	sp = __tdp_mmu_alloc_sp_for_split();
 
 	if (shared)
 		read_lock(&kvm->mmu_lock);