From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 26 Aug 2020 13:16:53 +0200
Subject: PCI/MSI: Provide pci_dev_has_special_msi_domain() helper
Git-commit: 2fd602669ee6d749a7dc47b84b87cef1a5075999
Patch-mainline: v5.10-rc1
References: jsc#SLE-16823

Provide a helper function to check whether a PCI device is handled by a
non-standard PCI/MSI domain. This will be used to exclude such devices
which hang of a special bus, e.g. VMD, to be excluded from the irq domain
override in irq remapping.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20200826112333.139387358@linutronix.de

Acked-by: Joerg Roedel <jroedel@suse.de>
---
 drivers/pci/msi.c   |   22 ++++++++++++++++++++++
 include/linux/msi.h |    1 +
 2 files changed, 23 insertions(+)

--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1573,4 +1573,26 @@ struct irq_domain *pci_msi_get_device_do
 					     DOMAIN_BUS_PCI_MSI);
 	return dom;
 }
+
+/**
+ * pci_dev_has_special_msi_domain - Check whether the device is handled by
+ *				    a non-standard PCI-MSI domain
+ * @pdev:	The PCI device to check.
+ *
+ * Returns: True if the device irqdomain or the bus irqdomain is
+ * non-standard PCI/MSI.
+ */
+bool pci_dev_has_special_msi_domain(struct pci_dev *pdev)
+{
+	struct irq_domain *dom = dev_get_msi_domain(&pdev->dev);
+
+	if (!dom)
+		dom = dev_get_msi_domain(&pdev->bus->dev);
+
+	if (!dom)
+		return true;
+
+	return dom->bus_token != DOMAIN_BUS_PCI_MSI;
+}
+
 #endif /* CONFIG_PCI_MSI_IRQ_DOMAIN */
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -373,6 +373,7 @@ int pci_msi_domain_check_cap(struct irq_
 			     struct msi_domain_info *info, struct device *dev);
 u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
 struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev);
+bool pci_dev_has_special_msi_domain(struct pci_dev *pdev);
 #else
 static inline struct irq_domain *pci_msi_get_device_domain(struct pci_dev *pdev)
 {