[tip: x86/irq] irqdomain/msi: Provide DOMAIN_BUS_VMD_MSI

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/irq branch of tip:

Commit-ID:     c6c9e2838c5f0b94773511586123bcb125757f2a
Gitweb:        https://git.kernel.org/tip/c6c9e2838c5f0b94773511586123bcb125757f2a
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Wed, 26 Aug 2020 13:16:51 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Wed, 16 Sep 2020 16:52:36 +02:00

irqdomain/msi: Provide DOMAIN_BUS_VMD_MSI

PCI devices behind a VMD bus are not subject to interrupt remapping, but
the irq domain for VMD MSI cannot be distinguished from a regular PCI/MSI
irq domain.

Add a new domain bus token and allow it in the bus token check in
msi_check_reservation_mode() to keep the functionality the same once VMD
uses this token.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
Acked-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
Link: https://lore.kernel.org/r/20200826112332.954409970@xxxxxxxxxxxxx

---
 include/linux/irqdomain.h | 1 +
 kernel/irq/msi.c          | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index b37350c..44445d9 100644
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -84,6 +84,7 @@ enum irq_domain_bus_token {
 	DOMAIN_BUS_FSL_MC_MSI,
 	DOMAIN_BUS_TI_SCI_INTA_MSI,
 	DOMAIN_BUS_WAKEUP,
+	DOMAIN_BUS_VMD_MSI,
 };
 
 /**
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 640668e..616b958 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -364,8 +364,13 @@ static bool msi_check_reservation_mode(struct irq_domain *domain,
 {
 	struct msi_desc *desc;
 
-	if (domain->bus_token != DOMAIN_BUS_PCI_MSI)
+	switch(domain->bus_token) {
+	case DOMAIN_BUS_PCI_MSI:
+	case DOMAIN_BUS_VMD_MSI:
+		break;
+	default:
 		return false;
+	}
 
 	if (!(info->flags & MSI_FLAG_MUST_REACTIVATE))
 		return false;