[patch RFC 21/38] PCI: MSI: Provide pci_dev_has_special_msi_domain() helper

Thomas Gleixner
2020-08-21T02:19:00Z

[-- Attachment #1: genirq-msi--Provide-pci_dev_has_special_msi_domain --]
[-- Type: text/plain, Size: 1692 bytes --]

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>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
---
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
@@ -1553,4 +1553,26 @@ 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
@@ -374,6 +374,7 @@ 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)
{