KVM: X86: Calculate quadrant when !role.gpte_is_8_bytes

role.quadrant is only valid when gpte size is 4 bytes and only be
calculated when gpte size is 4 bytes.

Although "vcpu->arch.mmu->root_level <= PT32_ROOT_LEVEL" also means
gpte size is 4 bytes, but using "!role.gpte_is_8_bytes" is clearer
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211118110814.2568-15-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/mmu/mmu.c

@@ -2087,7 +2087,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
 	role.level = level;
 	role.direct = direct;
 	role.access = access;
-	if (!direct_mmu && vcpu->arch.mmu->root_level <= PT32_ROOT_LEVEL) {
+	if (!direct_mmu && !role.gpte_is_8_bytes) {
 		quadrant = gaddr >> (PAGE_SHIFT + (PT64_PT_BITS * level));
 		quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1;
 		role.quadrant = quadrant;