[PATCH v4 03/12] KVM: arm64: Introduce new MMIO region for the ITS base address

[Andre Przywara]

The ARM GICv3 ITS controller requires a separate register frame to
cover ITS specific registers. Add a new VGIC address type and store
the address in a field in the vgic_dist structure.
Provide a function to check whether userland has provided the address,
so ITS functionality can be guarded by that check.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 Documentation/virtual/kvm/devices/arm-vgic.txt |  9 +++++++++
 arch/arm64/include/uapi/asm/kvm.h              |  2 ++
 include/kvm/vgic/vgic.h                        |  5 +++++
 virt/kvm/arm/vgic/vgic.c                       | 10 ++++++++++
 virt/kvm/arm/vgic/vgic_init.c                  |  1 +
 virt/kvm/arm/vgic/vgic_kvm_device.c            |  7 +++++++
 6 files changed, 34 insertions(+)

diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt
index 59541d4..087e2d9 100644
--- a/Documentation/virtual/kvm/devices/arm-vgic.txt
+++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
@@ -39,6 +39,15 @@ Groups:
       Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
       This address needs to be 64K aligned.
 
+    KVM_VGIC_V3_ADDR_TYPE_ITS (rw, 64-bit)
+      Base address in the guest physical address space of the GICv3 ITS
+      control register frame. The ITS allows MSI(-X) interrupts to be
+      injected into guests. This extension is optional, if the kernel
+      does not support the ITS, the call returns -ENODEV.
+      This memory is solely for the guest to access the ITS control
+      registers and does not cover the ITS translation register.
+      Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
+      This address needs to be 64K aligned and the region covers 64 KByte.
 
   KVM_DEV_ARM_VGIC_GRP_DIST_REGS
   Attributes:
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index f209ea1..c2b257d 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -87,9 +87,11 @@ struct kvm_regs {
 /* Supported VGICv3 address types  */
 #define KVM_VGIC_V3_ADDR_TYPE_DIST	2
 #define KVM_VGIC_V3_ADDR_TYPE_REDIST	3
+#define KVM_VGIC_V3_ADDR_TYPE_ITS	4
 
 #define KVM_VGIC_V3_DIST_SIZE		SZ_64K
 #define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)
+#define KVM_VGIC_V3_ITS_SIZE		SZ_64K
 
 #define KVM_ARM_VCPU_POWER_OFF		0 /* CPU is started in OFF state */
 #define KVM_ARM_VCPU_EL1_32BIT		1 /* CPU running a 32bit VM */
diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index 7c1d145..11344e6 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -135,6 +135,9 @@ struct vgic_dist {
 		gpa_t			vgic_redist_base;
 	};
 
+	/* The base address of the ITS control register frame */
+	gpa_t			vgic_its_base;
+
 	/* distributor enabled */
 	u32			enabled;
 
@@ -253,4 +256,6 @@ static inline int kvm_vgic_get_max_vcpus(void)
 	return kvm_vgic_global_state.max_gic_vcpus;
 }
 
+bool vgic_has_its(struct kvm *kvm);
+
 #endif /* __ASM_ARM_KVM_VGIC_VGIC_H */
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 65395af..1de2478 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -612,3 +612,13 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, u32 intid)
 
 	return map_is_active;
 }
+
+bool vgic_has_its(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+
+	if (dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3)
+		return false;
+
+	return !IS_VGIC_ADDR_UNDEF(dist->vgic_its_base);
+}
diff --git a/virt/kvm/arm/vgic/vgic_init.c b/virt/kvm/arm/vgic/vgic_init.c
index ac655b5..2301e03 100644
--- a/virt/kvm/arm/vgic/vgic_init.c
+++ b/virt/kvm/arm/vgic/vgic_init.c
@@ -132,6 +132,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
 	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
 	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
+	kvm->arch.vgic.vgic_its_base = VGIC_ADDR_UNDEF;
 
 out_unlock:
 	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
diff --git a/virt/kvm/arm/vgic/vgic_kvm_device.c b/virt/kvm/arm/vgic/vgic_kvm_device.c
index 7f78a16..3ec2ac3 100644
--- a/virt/kvm/arm/vgic/vgic_kvm_device.c
+++ b/virt/kvm/arm/vgic/vgic_kvm_device.c
@@ -109,6 +109,12 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
 		block_size = KVM_VGIC_V3_REDIST_SIZE;
 		alignment = SZ_64K;
 		break;
+	case KVM_VGIC_V3_ADDR_TYPE_ITS:
+		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
+		addr_ptr = &vgic->vgic_its_base;
+		block_size = KVM_VGIC_V3_ITS_SIZE;
+		alignment = SZ_64K;
+		break;
 #endif
 	default:
 		r = -ENODEV;
@@ -495,6 +501,7 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
 		switch (attr->attr) {
 		case KVM_VGIC_V3_ADDR_TYPE_DIST:
 		case KVM_VGIC_V3_ADDR_TYPE_REDIST:
+		case KVM_VGIC_V3_ADDR_TYPE_ITS:
 			return 0;
 		}
 		break;
-- 
2.7.3