diff --git a/include/linux/msi.h b/include/linux/msi.h
index a65cc47d06105f12422d566d9892a9fd0a007952..0180534b542838bd8c1195816893a6d174d7b7e1 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -241,6 +241,10 @@ struct msi_domain_info;
  * @msi_finish:		Optional callback to finalize the allocation
  * @set_desc:		Set the msi descriptor for an interrupt
  * @handle_error:	Optional error handler if the allocation fails
+ * @domain_alloc_irqs:	Optional function to override the default allocation
+ *			function.
+ * @domain_free_irqs:	Optional function to override the default free
+ *			function.
  *
  * @get_hwirq, @msi_init and @msi_free are callbacks used by
  * msi_create_irq_domain() and related interfaces
@@ -248,6 +252,22 @@ struct msi_domain_info;
  * @msi_check, @msi_prepare, @msi_finish, @set_desc and @handle_error
  * are callbacks used by msi_domain_alloc_irqs() and related
  * interfaces which are based on msi_desc.
+ *
+ * @domain_alloc_irqs, @domain_free_irqs can be used to override the
+ * default allocation/free functions (__msi_domain_alloc/free_irqs). This
+ * is initially for a wrapper around XENs seperate MSI universe which can't
+ * be wrapped into the regular irq domains concepts by mere mortals.  This
+ * allows to universally use msi_domain_alloc/free_irqs without having to
+ * special case XEN all over the place.
+ *
+ * Contrary to other operations @domain_alloc_irqs and @domain_free_irqs
+ * are set to the default implementation if NULL and even when
+ * MSI_FLAG_USE_DEF_DOM_OPS is not set to avoid breaking existing users and
+ * because these callbacks are obviously mandatory.
+ *
+ * This is NOT meant to be abused, but it can be useful to build wrappers
+ * for specialized MSI irq domains which need extra work before and after
+ * calling __msi_domain_alloc_irqs()/__msi_domain_free_irqs().
  */
 struct msi_domain_ops {
 	irq_hw_number_t	(*get_hwirq)(struct msi_domain_info *info,
@@ -270,6 +290,10 @@ struct msi_domain_ops {
 				    struct msi_desc *desc);
 	int		(*handle_error)(struct irq_domain *domain,
 					struct msi_desc *desc, int error);
+	int		(*domain_alloc_irqs)(struct irq_domain *domain,
+					     struct device *dev, int nvec);
+	void		(*domain_free_irqs)(struct irq_domain *domain,
+					    struct device *dev);
 };
 
 /**
@@ -327,8 +351,11 @@ int msi_domain_set_affinity(struct irq_data *data, const struct cpumask *mask,
 struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
 					 struct msi_domain_info *info,
 					 struct irq_domain *parent);
+int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
+			    int nvec);
 int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 			  int nvec);
+void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
 void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev);
 struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain);
 
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 616b9583cfbb78e87f19a3f716800e1fb64b9705..2c0c4d6d0f83afcc0d70b696e4b216ed06086106 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -229,11 +229,13 @@ static int msi_domain_ops_check(struct irq_domain *domain,
 }
 
 static struct msi_domain_ops msi_domain_ops_default = {
-	.get_hwirq	= msi_domain_ops_get_hwirq,
-	.msi_init	= msi_domain_ops_init,
-	.msi_check	= msi_domain_ops_check,
-	.msi_prepare	= msi_domain_ops_prepare,
-	.set_desc	= msi_domain_ops_set_desc,
+	.get_hwirq		= msi_domain_ops_get_hwirq,
+	.msi_init		= msi_domain_ops_init,
+	.msi_check		= msi_domain_ops_check,
+	.msi_prepare		= msi_domain_ops_prepare,
+	.set_desc		= msi_domain_ops_set_desc,
+	.domain_alloc_irqs	= __msi_domain_alloc_irqs,
+	.domain_free_irqs	= __msi_domain_free_irqs,
 };
 
 static void msi_domain_update_dom_ops(struct msi_domain_info *info)
@@ -245,6 +247,14 @@ static void msi_domain_update_dom_ops(struct msi_domain_info *info)
 		return;
 	}
 
+	if (ops->domain_alloc_irqs == NULL)
+		ops->domain_alloc_irqs = msi_domain_ops_default.domain_alloc_irqs;
+	if (ops->domain_free_irqs == NULL)
+		ops->domain_free_irqs = msi_domain_ops_default.domain_free_irqs;
+
+	if (!(info->flags & MSI_FLAG_USE_DEF_DOM_OPS))
+		return;
+
 	if (ops->get_hwirq == NULL)
 		ops->get_hwirq = msi_domain_ops_default.get_hwirq;
 	if (ops->msi_init == NULL)
@@ -278,8 +288,7 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
-	if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
-		msi_domain_update_dom_ops(info);
+	msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		msi_domain_update_chip_ops(info);
 
@@ -386,17 +395,8 @@ static bool msi_check_reservation_mode(struct irq_domain *domain,
 	return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
 }
 
-/**
- * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
- * @domain:	The domain to allocate from
- * @dev:	Pointer to device struct of the device for which the interrupts
- *		are allocated
- * @nvec:	The number of interrupts to allocate
- *
- * Returns 0 on success or an error code.
- */
-int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
-			  int nvec)
+int __msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
+			    int nvec)
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
@@ -490,12 +490,24 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 }
 
 /**
- * msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated tp @dev
- * @domain:	The domain to managing the interrupts
+ * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
+ * @domain:	The domain to allocate from
  * @dev:	Pointer to device struct of the device for which the interrupts
- *		are free
+ *		are allocated
+ * @nvec:	The number of interrupts to allocate
+ *
+ * Returns 0 on success or an error code.
  */
-void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
+int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
+			  int nvec)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+
+	return ops->domain_alloc_irqs(domain, dev, nvec);
+}
+
+void __msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
 {
 	struct msi_desc *desc;
 
@@ -512,6 +524,20 @@ void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
 	}
 }
 
+/**
+ * __msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated tp @dev
+ * @domain:	The domain to managing the interrupts
+ * @dev:	Pointer to device struct of the device for which the interrupts
+ *		are free
+ */
+void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
+{
+	struct msi_domain_info *info = domain->host_data;
+	struct msi_domain_ops *ops = info->ops;
+
+	return ops->domain_free_irqs(domain, dev);
+}
+
 /**
  * msi_get_domain_info - Get the MSI interrupt domain info for @domain
  * @domain:	The interrupt domain to retrieve data from