[PATCH v6 15/15] KVM: arm64: enable ITS emulation as a virtual MSI controller

[Andre Przywara]

Now that all ITS emulation functionality is in place, we advertise
MSI functionality to userland and also the ITS device to the guest - if
userland has configured that.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
 Documentation/virtual/kvm/api.txt |  2 +-
 arch/arm64/kvm/Kconfig            |  1 +
 arch/arm64/kvm/reset.c            | 10 ++++++++++
 include/kvm/vgic/vgic.h           |  5 +++++
 virt/kvm/arm/vgic.c               |  5 +++++
 virt/kvm/arm/vgic/vgic-init.c     |  3 +++
 virt/kvm/arm/vgic/vgic-mmio-v3.c  | 14 ++++++++++----
 virt/kvm/arm/vgic/vgic.c          |  8 ++++++++
 8 files changed, 43 insertions(+), 5 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index bf76639..f60b137 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2156,7 +2156,7 @@ after pausing the vcpu, but before it is resumed.
 4.71 KVM_SIGNAL_MSI
 
 Capability: KVM_CAP_SIGNAL_MSI
-Architectures: x86
+Architectures: x86 arm64
 Type: vm ioctl
 Parameters: struct kvm_msi (in)
 Returns: >0 on delivery, 0 if guest blocked the MSI, and -1 on error
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index c4f26ef..446686a 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -36,6 +36,7 @@ config KVM
 	select HAVE_KVM_IRQFD
 	select KVM_ARM_VGIC_V3
 	select KVM_ARM_PMU if HW_PERF_EVENTS
+	select HAVE_KVM_MSI
 	---help---
 	  Support hosting virtualized guest machines.
 	  We don't support KVM with 16K page tables yet, due to the multiple
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 6ec9dfe..409d188 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -86,6 +86,16 @@ int kvm_arch_dev_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_VCPU_ATTRIBUTES:
 		r = 1;
 		break;
+	case KVM_CAP_MSI_DEVID:
+#ifdef CONFIG_KVM_NEW_VGIC
+		if (!kvm)
+			r = -EINVAL;
+		else
+			r = kvm->arch.vgic.msis_require_devid;
+#else
+		r = -EINVAL;
+#endif
+		break;
 	default:
 		r = 0;
 	}
diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index fdc2781..f9ba335 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -153,6 +153,9 @@ struct vgic_dist {
 	/* vGIC model the kernel emulates for the guest (GICv2 or GICv3) */
 	u32			vgic_model;
 
+	/* Do injected MSIs require an additional device ID? */
+	bool			msis_require_devid;
+
 	int			nr_spis;
 
 	/* TODO: Consider moving to global state */
@@ -295,4 +298,6 @@ static inline int kvm_vgic_get_max_vcpus(void)
 	return kvm_vgic_global_state.max_gic_vcpus;
 }
 
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi);
+
 #endif /* __ASM_ARM_KVM_VGIC_VGIC_H */
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index c3bfbb9..26db30a 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -2438,3 +2438,8 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
 {
 	return 0;
 }
+
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+	return -ENODEV;
+}
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index d22b094..af76e9c 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -258,6 +258,9 @@ int vgic_init(struct kvm *kvm)
 	if (ret)
 		goto out;
 
+	if (vgic_has_its(kvm))
+		dist->msis_require_devid = true;
+
 	kvm_for_each_vcpu(i, vcpu, kvm)
 		kvm_vgic_vcpu_init(vcpu);
 
diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
index da74d67..cad81ae 100644
--- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
+++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
@@ -66,7 +66,12 @@ static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 	case GICD_TYPER:
 		value = vcpu->kvm->arch.vgic.nr_spis + VGIC_NR_PRIVATE_IRQS;
 		value = (value >> 5) - 1;
-		value |= (INTERRUPT_ID_BITS_SPIS - 1) << 19;
+		if (vgic_has_its(vcpu->kvm)) {
+			value |= (INTERRUPT_ID_BITS_ITS - 1) << 19;
+			value |= GICD_TYPER_LPIS;
+		} else {
+			value |= (INTERRUPT_ID_BITS_SPIS - 1) << 19;
+		}
 		break;
 	case GICD_IIDR:
 		value = (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
@@ -157,9 +162,8 @@ static void vgic_mmio_write_v3r_ctlr(struct kvm_vcpu *vcpu,
 
 	vgic_cpu->lpis_enabled = val & GICR_CTLR_ENABLE_LPIS;
 
-	if (!was_enabled && vgic_cpu->lpis_enabled) {
-		/* Eventually do something */
-	}
+	if (!was_enabled && vgic_cpu->lpis_enabled)
+		vgic_enable_lpis(vcpu);
 }
 
 static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
@@ -173,6 +177,8 @@ static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
 	value |= ((target_vcpu_id & 0xffff) << 8);
 	if (target_vcpu_id == atomic_read(&vcpu->kvm->online_vcpus) - 1)
 		value |= GICR_TYPER_LAST;
+	if (vgic_has_its(vcpu->kvm))
+		value |= GICR_TYPER_PLPIS;
 
 	return extract_bytes(value, addr & 7, len);
 }
diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index 4655ae4..4deded6 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -639,3 +639,11 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
 
 	return map_is_active;
 }
+
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
+{
+	if (vgic_has_its(kvm))
+		return vits_inject_msi(kvm, msi);
+	else
+		return -ENODEV;
+}
-- 
2.8.2