Subject: [PATCH v2 17/39] KVM: arm64: gic-v5: Introduce struct vgic_v5_irs and IRS base address

From: Sascha Bischoff <[email-masked]>
Date: Thu, 21 May 2026 14:54:58 +0000

In order to properly emulate the operation of the IRS from KVM, we
require storage for the MMIO register state. This change introduces
struct vgic_v5_irs, and adds a pointer to it to the struct vgic_dist.

This new data structure contains the storage for IRS MMIO state that
is required for emulating the MMIO interface in KVM. This provides
persistent storage, and a way to track data across MMIO writes, e.g.,
selecting an SPI and updating the configuration of it is two MMIO
writes.

Note that only a pointer to the data structure is added to struct
vgic_dist as this new structure is very large, and hence it makes
sense to dynamically allocate it and just provide a pointer to
retrieve it in struct vgic_dist.

In addition to adding a structure to store the MMIO state for the IRS,
we add the base address in GPA space to struct vgic_v5_irs.

Signed-off-by: Sascha Bischoff <[email-masked]>
---
 include/kvm/arm_vgic.h | 86 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index faecde764fea3..25368c5cda5df 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -409,6 +409,87 @@ struct vgic_v5_vm {
 	bool			vmte_allocated;
 };
 
+/*** GICv5 ***/
+struct vgic_v5_irs {
+	/* base addresses in guest physical address space: */
+	gpa_t vgic_v5_irs_base;
+
+	struct vgic_io_device iodev;
+	struct kvm_device *dev;
+
+	/* IRS state - used for registers etc */
+	struct {
+		u8 domain;
+		u8 pa_range;
+		bool virt;
+		bool setlpi;
+		bool mec;
+		bool mpam;
+		bool swe;
+		u16 irs_id;
+	} idr0;
+
+	struct {
+		/* PE_CNT is populated from online_vcpus at runtime */
+		u8 priority_bits;
+	} idr1;
+
+	struct {
+		u8 id_bits;
+		u8 min_lpi_id_bits;
+		bool ist_levels;
+		u8 ist_l2sz;
+		bool istmd;
+		u8 istmd_sz;
+	} idr2;
+
+	struct {
+		u32 spi_range;
+	} idr5;
+
+	struct {
+		u32 spi_irs_range;
+	} idr6;
+
+	struct {
+		u32 spi_base;
+	} idr7;
+
+	struct {
+		u8 sh;
+		u8 oc;
+		u8 ic;
+		bool ist_ra;
+		bool ist_wa;
+		bool vmt_ra;
+		bool vpet_ra;
+		bool vmd_ra;
+		bool vmd_wa;
+		bool vped_ra;
+		bool vped_wa;
+	} cr1;
+
+	struct {
+		u32 id;
+	} spi_selr;
+
+	struct {
+		u32 iaffid;
+	} pe_selr;
+
+	struct {
+		u8 lpi_id_bits;
+		u8 l2sz;
+		u8 istsz;
+		bool structure;
+	} ist_cfgr;
+
+	struct {
+		bool valid;
+		u64 addr;
+	} ist_baser;
+};
+
 struct vgic_dist {
 	bool			in_kernel;
 	bool			ready;
@@ -486,6 +567,11 @@ struct vgic_dist {
 	 * GICv5 per-VM data.
 	 */
 	struct vgic_v5_vm	gicv5_vm;
+
+	/*
+	 * GICv5 IRS data. Dynamically allocated due to the size.
+	 */
+	struct vgic_v5_irs	*vgic_v5_irs_data;
 };
 
 struct vgic_v2_cpu_if {
-- 
2.34.1