irqchip/gic-v5: Provide OF IRS config frame attrs to KVM

KVM needs to interact with the host IRS in order to, for example, make
VMs or VPEs valid. There are two potential approaches here. Either the
host irqchip driver can provide an interface, or KVM can interact
directly with the host IRS. The latter of these two is chosen as the
set of MMIO registers that KVM needs to interact with is orthogonal to
the set used by the host irqchip driver (with the exception of some of
the read-only IRS_IDRx registers).

Pass KVM a pointer to an IRS config frame - the config frame belonging
to ANY IRS is fine as long as one IRS's config frame is used
consistently - in struct gic_kvm_info. Additionally, include a flag
telling KVM whether the IRS is coherent or non-coherent in order to
make sure that KVM can do the correct cache state management, if
required.

Only OF (Device Tree) is supported with this change. ACPI is not.

Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Link: https://patch.msgid.link/20260904113404.4051341-3-sascha.bischoff@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

2 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/irqchip/arm-gic-v5.h b/include/linux/irqchip/arm-gic-v5.h
index 2c2fb39f049c..59a587585431 100644
--- a/include/linux/irqchip/arm-gic-v5.h
+++ b/include/linux/irqchip/arm-gic-v5.h
@@ -332,6 +332,8 @@ struct gicv5_irs_chip_data {
 	raw_spinlock_t		spi_config_lock;
 };
 
+#define IRS_FLAGS_NON_COHERENT		BIT(0)
+
 static inline int gicv5_wait_for_op_s_atomic(void __iomem *addr, u32 offset,
 					     const char *reg_s, u32 mask,
 					     u32 *val)
@@ -379,6 +381,7 @@ void __init gicv5_free_lpi_domain(void);
 
 int gicv5_irs_of_probe(struct device_node *parent);
 int gicv5_irs_acpi_probe(void);
+struct gicv5_irs_chip_data *gicv5_irs_get_chip_data(void);
 void gicv5_irs_remove(void);
 int gicv5_irs_enable(void);
 void gicv5_irs_its_probe(void);
diff --git a/include/linux/irqchip/arm-vgic-info.h b/include/linux/irqchip/arm-vgic-info.h
index 67d9d960273b..f05370e2debf 100644
--- a/include/linux/irqchip/arm-vgic-info.h
+++ b/include/linux/irqchip/arm-vgic-info.h
@@ -38,6 +38,11 @@ struct gic_kvm_info {
 	bool		has_v4_1;
 	/* Deactivation impared, subpar stuff */
 	bool		no_hw_deactivation;
+	/* GICv5 IRS base */
+	struct {
+		void __iomem	*base;
+		bool		non_coherent;
+	}		gicv5_irs;
 };
 
 #ifdef CONFIG_KVM