[tip: irq/core] genirq/msi: Add size info to struct msi_domain_info

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     61bf992fc618503c910416f28afa0b015838b72b
Gitweb:        https://git.kernel.org/tip/61bf992fc618503c910416f28afa0b015838b72b
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Fri, 25 Nov 2022 00:25:51 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 05 Dec 2022 19:21:01 +01:00

genirq/msi: Add size info to struct msi_domain_info

To allow proper range checking especially for dynamic allocations add a
size field to struct msi_domain_info. If the field is 0 then the size is
unknown or unlimited (up to MSI_MAX_INDEX) to provide backwards
compability.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221124232325.501144862@xxxxxxxxxxxxx

---
 include/linux/msi.h |  5 +++++
 kernel/irq/msi.c    | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 7fb8737..08a0e2a 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -422,6 +422,10 @@ struct msi_domain_ops {
  * struct msi_domain_info - MSI interrupt domain data
  * @flags:		Flags to decribe features and capabilities
  * @bus_token:		The domain bus token
+ * @hwsize:		The hardware table size or the software index limit.
+ *			If 0 then the size is considered unlimited and
+ *			gets initialized to the maximum software index limit
+ *			by the domain creation code.
  * @ops:		The callback data structure
  * @chip:		Optional: associated interrupt chip
  * @chip_data:		Optional: associated interrupt chip data
@@ -433,6 +437,7 @@ struct msi_domain_ops {
 struct msi_domain_info {
 	u32				flags;
 	enum irq_domain_bus_token	bus_token;
+	unsigned int			hwsize;
 	struct msi_domain_ops		*ops;
 	struct irq_chip			*chip;
 	void				*chip_data;
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index c368116..0a38905 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -772,6 +772,17 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
 {
 	struct irq_domain *domain;
 
+	if (info->hwsize > MSI_XA_DOMAIN_SIZE)
+		return NULL;
+
+	/*
+	 * Hardware size 0 is valid for backwards compatibility and for
+	 * domains which are not backed by a hardware table. Grant the
+	 * maximum index space.
+	 */
+	if (!info->hwsize)
+		info->hwsize = MSI_XA_DOMAIN_SIZE;
+
 	msi_domain_update_dom_ops(info);
 	if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 		msi_domain_update_chip_ops(info);