KVM: arm64: vgic-its: Introduce ITS emulation file with MMIO framework

The ARM GICv3 ITS emulation code goes into a separate file, but needs
to be connected to the GICv3 emulation, of which it is an option.
The ITS MMIO handlers require the respective ITS pointer to be passed in,
so we amend the existing VGIC MMIO framework to let it cope with that.
Also we introduce the basic ITS data structure and initialize it, but
don't return any success yet, as we are not yet ready for the show.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

include/kvm/arm_vgic.h

@@ -108,15 +108,35 @@ struct vgic_irq {
 };
 
 struct vgic_register_region;
+struct vgic_its;
+
+enum iodev_type {
+	IODEV_CPUIF,
+	IODEV_DIST,
+	IODEV_REDIST,
+	IODEV_ITS
+};
 
 struct vgic_io_device {
 	gpa_t base_addr;
-	struct kvm_vcpu *redist_vcpu;
+	union {
+		struct kvm_vcpu *redist_vcpu;
+		struct vgic_its *its;
+	};
 	const struct vgic_register_region *regions;
+	enum iodev_type iodev_type;
 	int nr_regions;
 	struct kvm_io_device dev;
 };
 
+struct vgic_its {
+	/* The base address of the ITS control register frame */
+	gpa_t			vgic_its_base;
+
+	bool			enabled;
+	struct vgic_io_device	iodev;
+};
+
 struct vgic_dist {
 	bool			in_kernel;
 	bool			ready;

virt/kvm/arm/vgic/vgic-its.c

@@ -0,0 +1,103 @@
+/*
+ * GICv3 ITS emulation
+ *
+ * Copyright (C) 2015,2016 ARM Ltd.
+ * Author: Andre Przywara <andre.przywara@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/cpu.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+
+#include <linux/irqchip/arm-gic-v3.h>
+
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_mmu.h>
+
+#include "vgic.h"
+#include "vgic-mmio.h"
+
+#define REGISTER_ITS_DESC(off, rd, wr, length, acc)		\
+{								\
+	.reg_offset = off,					\
+	.len = length,						\
+	.access_flags = acc,					\
+	.its_read = rd,						\
+	.its_write = wr,					\
+}
+
+static unsigned long its_mmio_read_raz(struct kvm *kvm, struct vgic_its *its,
+				       gpa_t addr, unsigned int len)
+{
+	return 0;
+}
+
+static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
+			      gpa_t addr, unsigned int len, unsigned long val)
+{
+	/* Ignore */
+}
+
+static struct vgic_register_region its_registers[] = {
+	REGISTER_ITS_DESC(GITS_CTLR,
+		its_mmio_read_raz, its_mmio_write_wi, 4,
+		VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_IIDR,
+		its_mmio_read_raz, its_mmio_write_wi, 4,
+		VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_TYPER,
+		its_mmio_read_raz, its_mmio_write_wi, 8,
+		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_CBASER,
+		its_mmio_read_raz, its_mmio_write_wi, 8,
+		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_CWRITER,
+		its_mmio_read_raz, its_mmio_write_wi, 8,
+		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_CREADR,
+		its_mmio_read_raz, its_mmio_write_wi, 8,
+		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_BASER,
+		its_mmio_read_raz, its_mmio_write_wi, 0x40,
+		VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
+	REGISTER_ITS_DESC(GITS_IDREGS_BASE,
+		its_mmio_read_raz, its_mmio_write_wi, 0x30,
+		VGIC_ACCESS_32bit),
+};
+
+static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
+{
+	struct vgic_io_device *iodev = &its->iodev;
+	int ret;
+
+	if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
+		return -ENXIO;
+
+	iodev->regions = its_registers;
+	iodev->nr_regions = ARRAY_SIZE(its_registers);
+	kvm_iodevice_init(&iodev->dev, &kvm_io_gic_ops);
+
+	iodev->base_addr = its->vgic_its_base;
+	iodev->iodev_type = IODEV_ITS;
+	iodev->its = its;
+	mutex_lock(&kvm->slots_lock);
+	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, iodev->base_addr,
+				      KVM_VGIC_V3_ITS_SIZE, &iodev->dev);
+	mutex_unlock(&kvm->slots_lock);
+
+	return ret;
+}

virt/kvm/arm/vgic/vgic-mmio-v3.c

@@ -42,6 +42,16 @@ static u64 update_64bit_reg(u64 reg, unsigned int offset, unsigned int len,
 	return reg | ((u64)val << lower);
 }
 
+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 false;
+}
+
 static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
 					    gpa_t addr, unsigned int len)
 {
@@ -132,6 +142,32 @@ static void vgic_mmio_write_irouter(struct kvm_vcpu *vcpu,
 	vgic_put_irq(vcpu->kvm, irq);
 }
 
+static unsigned long vgic_mmio_read_v3r_ctlr(struct kvm_vcpu *vcpu,
+					     gpa_t addr, unsigned int len)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+
+	return vgic_cpu->lpis_enabled ? GICR_CTLR_ENABLE_LPIS : 0;
+}
+
+
+static void vgic_mmio_write_v3r_ctlr(struct kvm_vcpu *vcpu,
+				     gpa_t addr, unsigned int len,
+				     unsigned long val)
+{
+	struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+	bool was_enabled = vgic_cpu->lpis_enabled;
+
+	if (!vgic_has_its(vcpu->kvm))
+		return;
+
+	vgic_cpu->lpis_enabled = val & GICR_CTLR_ENABLE_LPIS;
+
+	if (!was_enabled && vgic_cpu->lpis_enabled) {
+		/* Eventually do something */
+	}
+}
+
 static unsigned long vgic_mmio_read_v3r_typer(struct kvm_vcpu *vcpu,
 					      gpa_t addr, unsigned int len)
 {
@@ -372,7 +408,7 @@ static const struct vgic_register_region vgic_v3_dist_registers[] = {
 
 static const struct vgic_register_region vgic_v3_rdbase_registers[] = {
 	REGISTER_DESC_WITH_LENGTH(GICR_CTLR,
-		vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
+		vgic_mmio_read_v3r_ctlr, vgic_mmio_write_v3r_ctlr, 4,
 		VGIC_ACCESS_32bit),
 	REGISTER_DESC_WITH_LENGTH(GICR_IIDR,
 		vgic_mmio_read_v3r_iidr, vgic_mmio_write_wi, 4,
@@ -450,6 +486,7 @@ int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
 
 		kvm_iodevice_init(&rd_dev->dev, &kvm_io_gic_ops);
 		rd_dev->base_addr = rd_base;
+		rd_dev->iodev_type = IODEV_REDIST;
 		rd_dev->regions = vgic_v3_rdbase_registers;
 		rd_dev->nr_regions = ARRAY_SIZE(vgic_v3_rdbase_registers);
 		rd_dev->redist_vcpu = vcpu;
@@ -464,6 +501,7 @@ int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t redist_base_address)
 
 		kvm_iodevice_init(&sgi_dev->dev, &kvm_io_gic_ops);
 		sgi_dev->base_addr = sgi_base;
+		sgi_dev->iodev_type = IODEV_REDIST;
 		sgi_dev->regions = vgic_v3_sgibase_registers;
 		sgi_dev->nr_regions = ARRAY_SIZE(vgic_v3_sgibase_registers);
 		sgi_dev->redist_vcpu = vcpu;

virt/kvm/arm/vgic/vgic-mmio.c

@@ -473,8 +473,7 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 {
 	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
 	const struct vgic_register_region *region;
-	struct kvm_vcpu *r_vcpu;
-	unsigned long data;
+	unsigned long data = 0;
 
 	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
 				       addr - iodev->base_addr);
@@ -483,8 +482,20 @@ static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 		return 0;
 	}
 
-	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
-	data = region->read(r_vcpu, addr, len);
+	switch (iodev->iodev_type) {
+	case IODEV_CPUIF:
+		return 1;
+	case IODEV_DIST:
+		data = region->read(vcpu, addr, len);
+		break;
+	case IODEV_REDIST:
+		data = region->read(iodev->redist_vcpu, addr, len);
+		break;
+	case IODEV_ITS:
+		data = region->its_read(vcpu->kvm, iodev->its, addr, len);
+		break;
+	}
+
 	vgic_data_host_to_mmio_bus(val, len, data);
 	return 0;
 }
@@ -494,7 +505,6 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 {
 	struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
 	const struct vgic_register_region *region;
-	struct kvm_vcpu *r_vcpu;
 	unsigned long data = vgic_data_mmio_bus_to_host(val, len);
 
 	region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
@@ -505,8 +515,20 @@ static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
 	if (!check_region(region, addr, len))
 		return 0;
 
-	r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
-	region->write(r_vcpu, addr, len, data);
+	switch (iodev->iodev_type) {
+	case IODEV_CPUIF:
+		break;
+	case IODEV_DIST:
+		region->write(vcpu, addr, len, data);
+		break;
+	case IODEV_REDIST:
+		region->write(iodev->redist_vcpu, addr, len, data);
+		break;
+	case IODEV_ITS:
+		region->its_write(vcpu->kvm, iodev->its, addr, len, data);
+		break;
+	}
+
 	return 0;
 }
 
@@ -536,6 +558,7 @@ int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
 	}
 
 	io_device->base_addr = dist_base_address;
+	io_device->iodev_type = IODEV_DIST;
 	io_device->redist_vcpu = NULL;
 
 	mutex_lock(&kvm->slots_lock);

virt/kvm/arm/vgic/vgic-mmio.h

@@ -21,10 +21,19 @@ struct vgic_register_region {
 	unsigned int len;
 	unsigned int bits_per_irq;
 	unsigned int access_flags;
-	unsigned long (*read)(struct kvm_vcpu *vcpu, gpa_t addr,
-			      unsigned int len);
-	void (*write)(struct kvm_vcpu *vcpu, gpa_t addr, unsigned int len,
-		      unsigned long val);
+	union {
+		unsigned long (*read)(struct kvm_vcpu *vcpu, gpa_t addr,
+				      unsigned int len);
+		unsigned long (*its_read)(struct kvm *kvm, struct vgic_its *its,
+					  gpa_t addr, unsigned int len);
+	};
+	union {
+		void (*write)(struct kvm_vcpu *vcpu, gpa_t addr,
+			      unsigned int len, unsigned long val);
+		void (*its_write)(struct kvm *kvm, struct vgic_its *its,
+				  gpa_t addr, unsigned int len,
+				  unsigned long val);
+	};
 };
 
 extern struct kvm_io_device_ops kvm_io_gic_ops;

virt/kvm/arm/vgic/vgic.h

@@ -72,6 +72,7 @@ void vgic_v3_enable(struct kvm_vcpu *vcpu);
 int vgic_v3_probe(const struct gic_kvm_info *info);
 int vgic_v3_map_resources(struct kvm *kvm);
 int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
+bool vgic_has_its(struct kvm *kvm);
 #else
 static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
 {
@@ -123,6 +124,12 @@ static inline int vgic_register_redist_iodevs(struct kvm *kvm,
 {
 	return -ENODEV;
 }
+
+static inline bool vgic_has_its(struct kvm *kvm)
+{
+	return false;
+}
+
 #endif
 
 int kvm_register_vgic_device(unsigned long type);