From: Marc Zyngier <marc.zyngier@arm.com>
Date: Fri, 27 Oct 2017 15:28:38 +0100
Subject: KVM: arm/arm64: GICv4: Add init/teardown of the per-VM vPE irq domain
Patch-mainline: v4.15-rc1
Git-commit: 74fe55dc9ab77142e3c4783ecc5b87d494164452
References: bsc#1077761

In order to control the GICv4 view of virtual CPUs, we rely
on an irqdomain allocated for that purpose. Let's add a couple
of helpers to that effect.

At the same time, the vgic data structures gain new fields to
track all this... erm... wonderful stuff.

The way we hook into the vgic init is slightly convoluted. We
need the vgic to be initialized (in order to guarantee that
the number of vcpus is now fixed), and we must have a vITS
(otherwise this is all very pointless). So we end-up calling
the init from both vgic_init and vgic_its_create.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Alexander Graf <agraf@suse.de>
---
 arch/arm/kvm/Makefile         |    1 
 arch/arm64/kvm/Makefile       |    1 
 include/kvm/arm_vgic.h        |   19 +++++++++
 virt/kvm/arm/vgic/vgic-init.c |    9 ++++
 virt/kvm/arm/vgic/vgic-its.c  |    8 ++++
 virt/kvm/arm/vgic/vgic-v4.c   |   83 ++++++++++++++++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic.h      |    2 +
 7 files changed, 123 insertions(+)
 create mode 100644 virt/kvm/arm/vgic/vgic-v4.c

--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -31,6 +31,7 @@
 obj-y += $(KVM)/arm/vgic/vgic-irqfd.o
 obj-y += $(KVM)/arm/vgic/vgic-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-v3.o
+obj-y += $(KVM)/arm/vgic/vgic-v4.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio-v2.o
 obj-y += $(KVM)/arm/vgic/vgic-mmio-v3.o
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -26,6 +26,7 @@
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-irqfd.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v2.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v3.o
+kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-v4.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v2.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic/vgic-mmio-v3.o
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -26,6 +26,8 @@
 #include <linux/list.h>
 #include <linux/jump_label.h>
 
+#include <linux/irqchip/arm-gic-v4.h>
+
 #define VGIC_V3_MAX_CPUS	255
 #define VGIC_V2_MAX_CPUS	8
 #define VGIC_NR_IRQS_LEGACY     256
@@ -236,6 +238,15 @@
 
 	/* used by vgic-debug */
 	struct vgic_state_iter *iter;
+
+	/*
+	 * GICv4 ITS per-VM data, containing the IRQ domain, the VPE
+	 * array, the property table pointer as well as allocation
+	 * data. This essentially ties the Linux IRQ core and ITS
+	 * together, and avoids leaking KVM's data structures anywhere
+	 * else.
+	 */
+	struct its_vm		its_vm;
 };
 
 struct vgic_v2_cpu_if {
@@ -254,6 +265,14 @@
 	u32		vgic_ap0r[4];
 	u32		vgic_ap1r[4];
 	u64		vgic_lr[VGIC_V3_MAX_LRS];
+
+	/*
+	 * GICv4 ITS per-VPE data, containing the doorbell IRQ, the
+	 * pending table pointer, the its_vm pointer and a few other
+	 * HW specific things. As for the its_vm structure, this is
+	 * linking the Linux IRQ subsystem and the ITS together.
+	 */
+	struct its_vpe	its_vpe;
 };
 
 struct vgic_cpu {
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -285,6 +285,12 @@
 	if (ret)
 		goto out;
 
+	if (vgic_supports_direct_msis(kvm)) {
+		ret = vgic_v4_init(kvm);
+		if (ret)
+			goto out;
+	}
+
 	kvm_for_each_vcpu(i, vcpu, kvm)
 		kvm_vgic_vcpu_enable(vcpu);
 
@@ -320,6 +326,9 @@
 
 	kfree(dist->spis);
 	dist->nr_spis = 0;
+
+	if (vgic_supports_direct_msis(kvm))
+		vgic_v4_teardown(kvm);
 }
 
 void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1649,6 +1649,14 @@
 	if (!its)
 		return -ENOMEM;
 
+	if (vgic_initialized(dev->kvm)) {
+		int ret = vgic_v4_init(dev->kvm);
+		if (ret) {
+			kfree(its);
+			return ret;
+		}
+	}
+
 	mutex_init(&its->its_lock);
 	mutex_init(&its->cmd_lock);
 
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-v4.c
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2017 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/kvm_host.h>
+
+#include "vgic.h"
+
+/**
+ * vgic_v4_init - Initialize the GICv4 data structures
+ * @kvm:	Pointer to the VM being initialized
+ *
+ * We may be called each time a vITS is created, or when the
+ * vgic is initialized. This relies on kvm->lock to be
+ * held. In both cases, the number of vcpus should now be
+ * fixed.
+ */
+int vgic_v4_init(struct kvm *kvm)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	struct kvm_vcpu *vcpu;
+	int i, nr_vcpus, ret;
+
+	if (dist->its_vm.vpes)
+		return 0;
+
+	nr_vcpus = atomic_read(&kvm->online_vcpus);
+
+	dist->its_vm.vpes = kzalloc(sizeof(*dist->its_vm.vpes) * nr_vcpus,
+				    GFP_KERNEL);
+	if (!dist->its_vm.vpes)
+		return -ENOMEM;
+
+	dist->its_vm.nr_vpes = nr_vcpus;
+
+	kvm_for_each_vcpu(i, vcpu, kvm)
+		dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
+
+	ret = its_alloc_vcpu_irqs(&dist->its_vm);
+	if (ret < 0) {
+		kvm_err("VPE IRQ allocation failure\n");
+		kfree(dist->its_vm.vpes);
+		dist->its_vm.nr_vpes = 0;
+		dist->its_vm.vpes = NULL;
+		return ret;
+	}
+
+	return ret;
+}
+
+/**
+ * vgic_v4_teardown - Free the GICv4 data structures
+ * @kvm:	Pointer to the VM being destroyed
+ *
+ * Relies on kvm->lock to be held.
+ */
+void vgic_v4_teardown(struct kvm *kvm)
+{
+	struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
+
+	if (!its_vm->vpes)
+		return;
+
+	its_free_vcpu_irqs(its_vm);
+	kfree(its_vm->vpes);
+	its_vm->nr_vpes = 0;
+	its_vm->vpes = NULL;
+}
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -242,5 +242,7 @@
 struct vgic_its *vgic_msi_to_its(struct kvm *kvm, struct kvm_msi *msi);
 
 bool vgic_supports_direct_msis(struct kvm *kvm);
+int vgic_v4_init(struct kvm *kvm);
+void vgic_v4_teardown(struct kvm *kvm);
 
 #endif