KVM: x86: Refactor kvm_hv_flush_tlb() to reduce indentation

Refactor the "extended" path of kvm_hv_flush_tlb() to reduce the nesting
depth for the non-fast sparse path, and to make the code more similar to
the extended path in kvm_hv_send_ipi().

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211207220926.718794-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/hyperv.c

@@ -1818,31 +1818,33 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool
 		if (hc->var_cnt != bitmap_weight((unsigned long *)&valid_bank_mask, 64))
 			return HV_STATUS_INVALID_HYPERCALL_INPUT;
 
-		if (!hc->var_cnt && !all_cpus)
+		if (all_cpus)
+			goto do_flush;
+
+		if (!hc->var_cnt)
 			goto ret_success;
 
-		if (!all_cpus) {
-			if (hc->fast) {
-				if (hc->var_cnt > HV_HYPERCALL_MAX_XMM_REGISTERS - 1)
-					return HV_STATUS_INVALID_HYPERCALL_INPUT;
-				for (i = 0; i < hc->var_cnt; i += 2) {
-					sparse_banks[i] = sse128_lo(hc->xmm[i / 2 + 1]);
-					sparse_banks[i + 1] = sse128_hi(hc->xmm[i / 2 + 1]);
-				}
-			} else {
-				if (hc->var_cnt > 64)
-					return HV_STATUS_INVALID_HYPERCALL_INPUT;
-
-				gpa = hc->ingpa + offsetof(struct hv_tlb_flush_ex,
-							   hv_vp_set.bank_contents);
-				if (unlikely(kvm_read_guest(kvm, gpa, sparse_banks,
-							    hc->var_cnt *
-							    sizeof(sparse_banks[0]))))
-					return HV_STATUS_INVALID_HYPERCALL_INPUT;
+		if (hc->fast) {
+			if (hc->var_cnt > HV_HYPERCALL_MAX_XMM_REGISTERS - 1)
+				return HV_STATUS_INVALID_HYPERCALL_INPUT;
+			for (i = 0; i < hc->var_cnt; i += 2) {
+				sparse_banks[i] = sse128_lo(hc->xmm[i / 2 + 1]);
+				sparse_banks[i + 1] = sse128_hi(hc->xmm[i / 2 + 1]);
 			}
+			goto do_flush;
 		}
+
+		if (hc->var_cnt > 64)
+			return HV_STATUS_INVALID_HYPERCALL_INPUT;
+
+		gpa = hc->ingpa + offsetof(struct hv_tlb_flush_ex,
+					   hv_vp_set.bank_contents);
+		if (unlikely(kvm_read_guest(kvm, gpa, sparse_banks,
+					    hc->var_cnt * sizeof(sparse_banks[0]))))
+			return HV_STATUS_INVALID_HYPERCALL_INPUT;
 	}
 
+do_flush:
 	/*
 	 * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't
 	 * analyze it here, flush TLB regardless of the specified address space.