From: Sascha Bischoff <Sascha.Bischoff@arm.com>
Date: Fri, 27 Jun 2025 10:09:01 +0000 (+0000)
Subject: irqchip/gic-v5: Populate struct gic_kvm_info
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1ec38ce3d024bebdff2a9ffb526e4d198605204d;p=thirdparty%2Flinux.git

irqchip/gic-v5: Populate struct gic_kvm_info

Populate the gic_kvm_info struct based on support for
FEAT_GCIE_LEGACY.  The struct is used by KVM to probe for a compatible
GIC.

Co-authored-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Link: https://lore.kernel.org/r/20250627100847.1022515-3-sascha.bischoff@arm.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---

diff --git a/drivers/irqchip/irq-gic-v5.c b/drivers/irqchip/irq-gic-v5.c
index 0e4789818131d..4bd224f359a78 100644
--- a/drivers/irqchip/irq-gic-v5.c
+++ b/drivers/irqchip/irq-gic-v5.c
@@ -13,6 +13,7 @@
 
 #include <linux/irqchip.h>
 #include <linux/irqchip/arm-gic-v5.h>
+#include <linux/irqchip/arm-vgic-info.h>
 
 #include <asm/cpufeature.h>
 #include <asm/exception.h>
@@ -1058,6 +1059,36 @@ static void gicv5_set_cpuif_idbits(void)
 	}
 }
 
+#ifdef CONFIG_KVM
+static struct gic_kvm_info gic_v5_kvm_info __initdata;
+
+static bool __init gicv5_cpuif_has_gcie_legacy(void)
+{
+	u64 idr0 = read_sysreg_s(SYS_ICC_IDR0_EL1);
+	return !!FIELD_GET(ICC_IDR0_EL1_GCIE_LEGACY, idr0);
+}
+
+static void __init gic_of_setup_kvm_info(struct device_node *node)
+{
+	gic_v5_kvm_info.type = GIC_V5;
+	gic_v5_kvm_info.has_gcie_v3_compat = gicv5_cpuif_has_gcie_legacy();
+
+	/* GIC Virtual CPU interface maintenance interrupt */
+	gic_v5_kvm_info.no_maint_irq_mask = false;
+	gic_v5_kvm_info.maint_irq = irq_of_parse_and_map(node, 0);
+	if (!gic_v5_kvm_info.maint_irq) {
+		pr_warn("cannot find GICv5 virtual CPU interface maintenance interrupt\n");
+		return;
+	}
+
+	vgic_set_kvm_info(&gic_v5_kvm_info);
+}
+#else
+static inline void __init gic_of_setup_kvm_info(struct device_node *node)
+{
+}
+#endif // CONFIG_KVM
+
 static int __init gicv5_of_init(struct device_node *node, struct device_node *parent)
 {
 	int ret = gicv5_irs_of_probe(node);
@@ -1090,6 +1121,8 @@ static int __init gicv5_of_init(struct device_node *node, struct device_node *pa
 
 	gicv5_irs_its_probe();
 
+	gic_of_setup_kvm_info(node);
+
 	return 0;
 
 out_int:
diff --git a/include/linux/irqchip/arm-vgic-info.h b/include/linux/irqchip/arm-vgic-info.h
index a75b2c7de69d0..ca1713fac6e3b 100644
--- a/include/linux/irqchip/arm-vgic-info.h
+++ b/include/linux/irqchip/arm-vgic-info.h
@@ -15,6 +15,8 @@ enum gic_type {
 	GIC_V2,
 	/* Full GICv3, optionally with v2 compat */
 	GIC_V3,
+	/* Full GICv5, optionally with v3 compat */
+	GIC_V5,
 };
 
 struct gic_kvm_info {
@@ -34,6 +36,8 @@ struct gic_kvm_info {
 	bool		has_v4_1;
 	/* Deactivation impared, subpar stuff */
 	bool		no_hw_deactivation;
+	/* v3 compat support (GICv5 hosts, only) */
+	bool		has_gcie_v3_compat;
 };
 
 #ifdef CONFIG_KVM