diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index fc9bb06d5411..7774b603a796 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -1340,6 +1340,7 @@ static int __init acpi_init(void)
 
 	pci_mmcfg_late_init();
 	acpi_iort_init();
+	acpi_viot_early_init();
 	acpi_hest_init();
 	ghes_init();
 	acpi_scan_init();
diff --git a/drivers/acpi/viot.c b/drivers/acpi/viot.c
index d2256326c73a..647f11cf165d 100644
--- a/drivers/acpi/viot.c
+++ b/drivers/acpi/viot.c
@@ -248,6 +248,26 @@ err_free:
 	return ret;
 }
 
+/**
+ * acpi_viot_early_init - Test the presence of VIOT and enable ACS
+ *
+ * If the VIOT does exist, ACS must be enabled. This cannot be
+ * done in acpi_viot_init() which is called after the bus scan
+ */
+void __init acpi_viot_early_init(void)
+{
+#ifdef CONFIG_PCI
+	acpi_status status;
+	struct acpi_table_header *hdr;
+
+	status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);
+	if (ACPI_FAILURE(status))
+		return;
+	pci_request_acs();
+	acpi_put_table(hdr);
+#endif
+}
+
 /**
  * acpi_viot_init - Parse the VIOT table
  *
@@ -319,12 +339,6 @@ static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)
 			epid = ((domain_nr - ep->segment_start) << 16) +
 				dev_id - ep->bdf_start + ep->endpoint_id;
 
-			/*
-			 * If we found a PCI range managed by the viommu, we're
-			 * the one that has to request ACS.
-			 */
-			pci_request_acs();
-
 			return viot_dev_iommu_init(&pdev->dev, ep->viommu,
 						   epid);
 		}
diff --git a/include/linux/acpi_viot.h b/include/linux/acpi_viot.h
index 1eb8ee5b0e5f..a5a122431563 100644
--- a/include/linux/acpi_viot.h
+++ b/include/linux/acpi_viot.h
@@ -6,9 +6,11 @@
 #include <linux/acpi.h>
 
 #ifdef CONFIG_ACPI_VIOT
+void __init acpi_viot_early_init(void);
 void __init acpi_viot_init(void);
 int viot_iommu_configure(struct device *dev);
 #else
+static inline void acpi_viot_early_init(void) {}
 static inline void acpi_viot_init(void) {}
 static inline int viot_iommu_configure(struct device *dev)
 {