diff mbox

[v4,49/56] KVM: arm/arm64: vgic-new: vgic_init: implement kvm_vgic_hyp_init

Message ID 1463392481-26583-50-git-send-email-andre.przywara@arm.com
State Superseded
Headers show

Commit Message

Andre Przywara May 16, 2016, 9:53 a.m. UTC
From: Eric Auger <eric.auger@linaro.org>


Implements kvm_vgic_hyp_init and vgic_probe function.
This uses the new firmware independent VGIC probing to support both ACPI
and DT based systems (code from Marc Zyngier).

The vgic_global struct is enriched with new fields populated
by those functions.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

---
Changelog v1 .. v2:
- rename vgic_init.c to vgic-init.c

Changelog v2 .. v3:
- include kvm/arm_vgic.h instead of kvm/vgic/vgic.h
- move ich_vtr_el2 variable into probe function

Changelog v3 .. v4:
- improve nr_lr determination in GICv2 probe
- switching to firmware-independent probing

 include/kvm/vgic/vgic.h       |   1 +
 virt/kvm/arm/vgic/vgic-init.c | 123 ++++++++++++++++++++++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic-v2.c   |  64 ++++++++++++++++++++++
 virt/kvm/arm/vgic/vgic-v3.c   |  49 +++++++++++++++++
 virt/kvm/arm/vgic/vgic.h      |   9 ++++
 5 files changed, 246 insertions(+)
 create mode 100644 virt/kvm/arm/vgic/vgic-init.c

-- 
2.8.2


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Comments

Christoffer Dall May 18, 2016, 2:08 p.m. UTC | #1
On Mon, May 16, 2016 at 10:53:37AM +0100, Andre Przywara wrote:
> From: Eric Auger <eric.auger@linaro.org>

> 

> Implements kvm_vgic_hyp_init and vgic_probe function.

> This uses the new firmware independent VGIC probing to support both ACPI

> and DT based systems (code from Marc Zyngier).

> 

> The vgic_global struct is enriched with new fields populated

> by those functions.

> 

> Signed-off-by: Eric Auger <eric.auger@linaro.org>

> Signed-off-by: Andre Przywara <andre.przywara@arm.com>

> ---

> Changelog v1 .. v2:

> - rename vgic_init.c to vgic-init.c

> 

> Changelog v2 .. v3:

> - include kvm/arm_vgic.h instead of kvm/vgic/vgic.h

> - move ich_vtr_el2 variable into probe function

> 

> Changelog v3 .. v4:

> - improve nr_lr determination in GICv2 probe

> - switching to firmware-independent probing

> 

>  include/kvm/vgic/vgic.h       |   1 +

>  virt/kvm/arm/vgic/vgic-init.c | 123 ++++++++++++++++++++++++++++++++++++++++++

>  virt/kvm/arm/vgic/vgic-v2.c   |  64 ++++++++++++++++++++++

>  virt/kvm/arm/vgic/vgic-v3.c   |  49 +++++++++++++++++

>  virt/kvm/arm/vgic/vgic.h      |   9 ++++

>  5 files changed, 246 insertions(+)

>  create mode 100644 virt/kvm/arm/vgic/vgic-init.c

> 

> diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h

> index 3689b9b..393489f 100644

> --- a/include/kvm/vgic/vgic.h

> +++ b/include/kvm/vgic/vgic.h

> @@ -195,6 +195,7 @@ struct vgic_cpu {

>  };

>  

>  int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);

> +int kvm_vgic_hyp_init(void);

>  

>  int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,

>  			bool level);

> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c

> new file mode 100644

> index 0000000..4523beb

> --- /dev/null

> +++ b/virt/kvm/arm/vgic/vgic-init.c

> @@ -0,0 +1,123 @@

> +/*

> + * Copyright (C) 2015, 2016 ARM Ltd.

> + *

> + * 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/uaccess.h>

> +#include <linux/interrupt.h>

> +#include <linux/cpu.h>

> +#include <linux/kvm_host.h>

> +#include <kvm/arm_vgic.h>

> +#include <asm/kvm_mmu.h>

> +#include "vgic.h"

> +

> +/* GENERIC PROBE */

> +

> +static void vgic_init_maintenance_interrupt(void *info)

> +{

> +	enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);

> +}

> +

> +static int vgic_cpu_notify(struct notifier_block *self,

> +			   unsigned long action, void *cpu)

> +{

> +	switch (action) {

> +	case CPU_STARTING:

> +	case CPU_STARTING_FROZEN:

> +		vgic_init_maintenance_interrupt(NULL);

> +		break;

> +	case CPU_DYING:

> +	case CPU_DYING_FROZEN:

> +		disable_percpu_irq(kvm_vgic_global_state.maint_irq);

> +		break;

> +	}

> +

> +	return NOTIFY_OK;

> +}

> +

> +static struct notifier_block vgic_cpu_nb = {

> +	.notifier_call = vgic_cpu_notify,

> +};

> +

> +static irqreturn_t vgic_maintenance_handler(int irq, void *data)

> +{

> +	/*

> +	 * We cannot rely on the vgic maintenance interrupt to be

> +	 * delivered synchronously. This means we can only use it to

> +	 * exit the VM, and we perform the handling of EOIed

> +	 * interrupts on the exit path (see vgic_process_maintenance).

> +	 */

> +	return IRQ_HANDLED;

> +}

> +

> +/**

> + * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable

> + * according to the host GIC model. Accordingly calls either

> + * vgic_v2/v3_probe which registers the KVM_DEVICE that can be

> + * instantiated by a guest later on .

> + */

> +int kvm_vgic_hyp_init(void)

> +{

> +	const struct gic_kvm_info *gic_kvm_info;

> +	int ret;

> +

> +	gic_kvm_info = gic_get_kvm_info();

> +	if (!gic_kvm_info)

> +		return -ENODEV;

> +

> +	if (!gic_kvm_info->maint_irq) {

> +		kvm_err("No vgic maintenance irq\n");

> +		return -ENXIO;

> +	}

> +

> +	switch (gic_kvm_info->type) {

> +	case GIC_V2:

> +		ret = vgic_v2_probe(gic_kvm_info);

> +		break;

> +	case GIC_V3:

> +		ret = vgic_v3_probe(gic_kvm_info);

> +		break;

> +	default:

> +		ret = -ENODEV;

> +	};

> +

> +	if (ret)

> +		return ret;

> +

> +	kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;

> +	ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,

> +				 vgic_maintenance_handler,

> +				 "vgic", kvm_get_running_vcpus());

> +	if (ret) {

> +		kvm_err("Cannot register interrupt %d\n",

> +			kvm_vgic_global_state.maint_irq);

> +		return ret;

> +	}

> +

> +	ret = __register_cpu_notifier(&vgic_cpu_nb);

> +	if (ret) {

> +		kvm_err("Cannot register vgic CPU notifier\n");

> +		goto out_free_irq;

> +	}

> +

> +	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);

> +

> +	kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);

> +	return 0;

> +

> +out_free_irq:

> +	free_percpu_irq(kvm_vgic_global_state.maint_irq,

> +			kvm_get_running_vcpus());

> +	return ret;

> +}

> diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c

> index d943059..09777c8 100644

> --- a/virt/kvm/arm/vgic/vgic-v2.c

> +++ b/virt/kvm/arm/vgic/vgic-v2.c

> @@ -17,6 +17,8 @@

>  #include <linux/irqchip/arm-gic.h>

>  #include <linux/kvm.h>

>  #include <linux/kvm_host.h>

> +#include <kvm/arm_vgic.h>

> +#include <asm/kvm_mmu.h>

>  

>  #include "vgic.h"

>  

> @@ -203,3 +205,65 @@ void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)

>  	vmcrp->pmr  = (vmcr & GICH_VMCR_PRIMASK_MASK) >>

>  			GICH_VMCR_PRIMASK_SHIFT;

>  }

> +

> +/**

> + * vgic_v2_probe - probe for a GICv2 compatible interrupt controller in DT

> + * @node:	pointer to the DT node

> + *

> + * Returns 0 if a GICv2 has been found, returns an error code otherwise

> + */

> +int vgic_v2_probe(const struct gic_kvm_info *info)

> +{

> +	int ret;

> +	u32 vtr;

> +

> +	if (!info->vctrl.start) {

> +		kvm_err("GICH not present in the firmware table\n");

> +		return -ENXIO;

> +	}

> +

> +	if (!PAGE_ALIGNED(info->vcpu.start)) {

> +		kvm_err("GICV physical address 0x%llx not page aligned\n",

> +			(unsigned long long)info->vcpu.start);

> +		return -ENXIO;

> +	}

> +

> +	if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {

> +		kvm_err("GICV size 0x%llx not a multiple of page size 0x%lx\n",

> +			(unsigned long long)resource_size(&info->vcpu),

> +			PAGE_SIZE);

> +		return -ENXIO;

> +	}

> +

> +	kvm_vgic_global_state.vctrl_base = ioremap(info->vctrl.start,

> +						   resource_size(&info->vctrl));

> +	if (!kvm_vgic_global_state.vctrl_base) {

> +		kvm_err("Cannot ioremap GICH\n");

> +		return -ENOMEM;

> +	}

> +

> +	vtr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_VTR);

> +	kvm_vgic_global_state.nr_lr = (vtr & 0x3f) + 1;

> +

> +	ret = create_hyp_io_mappings(kvm_vgic_global_state.vctrl_base,

> +				     kvm_vgic_global_state.vctrl_base +

> +					 resource_size(&info->vctrl),

> +				     info->vctrl.start);

> +

> +	if (ret) {

> +		kvm_err("Cannot map VCTRL into hyp\n");

> +		iounmap(kvm_vgic_global_state.vctrl_base);

> +		return ret;

> +	}

> +

> +	kvm_vgic_global_state.can_emulate_gicv2 = true;

> +	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);

> +

> +	kvm_vgic_global_state.vcpu_base = info->vcpu.start;

> +	kvm_vgic_global_state.type = VGIC_V2;

> +	kvm_vgic_global_state.max_gic_vcpus = VGIC_V2_MAX_CPUS;

> +

> +	kvm_info("vgic-v2@%llx\n", info->vctrl.start);

> +

> +	return 0;

> +}

> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c

> index 8548297..de0e8e0 100644

> --- a/virt/kvm/arm/vgic/vgic-v3.c

> +++ b/virt/kvm/arm/vgic/vgic-v3.c

> @@ -15,6 +15,9 @@

>  #include <linux/irqchip/arm-gic-v3.h>

>  #include <linux/kvm.h>

>  #include <linux/kvm_host.h>

> +#include <kvm/arm_vgic.h>

> +#include <asm/kvm_mmu.h>

> +#include <asm/kvm_asm.h>

>  

>  #include "vgic.h"

>  

> @@ -182,3 +185,49 @@ void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)

>  	vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;

>  	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;

>  }

> +

> +/**

> + * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT

> + * @node:	pointer to the DT node

> + *

> + * Returns 0 if a GICv3 has been found, returns an error code otherwise

> + */

> +int vgic_v3_probe(const struct gic_kvm_info *info)

> +{

> +	u32 ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);

> +

> +	/*

> +	 * The ListRegs field is 5 bits, but there is a architectural

> +	 * maximum of 16 list registers. Just ignore bit 4...

> +	 */

> +	kvm_vgic_global_state.nr_lr = (ich_vtr_el2 & 0xf) + 1;

> +	kvm_vgic_global_state.can_emulate_gicv2 = false;

> +

> +	if (!info->vcpu.start) {

> +		kvm_info("GICv3: no GICV resource entry\n");

> +		kvm_vgic_global_state.vcpu_base = 0;

> +	} else if (!PAGE_ALIGNED(info->vcpu.start)) {

> +		pr_warn("GICV physical address 0x%llx not page aligned\n",

> +			(unsigned long long)info->vcpu.start);

> +		kvm_vgic_global_state.vcpu_base = 0;

> +	} else if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {

> +		pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",

> +			(unsigned long long)resource_size(&info->vcpu),

> +			PAGE_SIZE);

> +		kvm_vgic_global_state.vcpu_base = 0;

> +	} else {

> +		kvm_vgic_global_state.vcpu_base = info->vcpu.start;

> +		kvm_vgic_global_state.can_emulate_gicv2 = true;

> +		kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);

> +		kvm_info("vgic-v2@%llx\n", info->vcpu.start);

> +	}

> +	if (kvm_vgic_global_state.vcpu_base == 0)

> +		kvm_info("disabling GICv2 emulation\n");

> +	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3);

> +

> +	kvm_vgic_global_state.vctrl_base = NULL;

> +	kvm_vgic_global_state.type = VGIC_V3;

> +	kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS;

> +

> +	return 0;

> +}

> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h

> index de9dc71..f4244b6 100644

> --- a/virt/kvm/arm/vgic/vgic.h

> +++ b/virt/kvm/arm/vgic/vgic.h

> @@ -16,6 +16,8 @@

>  #ifndef __KVM_ARM_VGIC_NEW_H__

>  #define __KVM_ARM_VGIC_NEW_H__

>  

> +#include <linux/irqchip/arm-gic-common.h>

> +

>  #define PRODUCT_ID_KVM		0x4b	/* ASCII code K */

>  #define IMPLEMENTER_ARM		0x43b

>  

> @@ -51,6 +53,7 @@ int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,

>  			  int offset, u32 *val);

>  void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

>  void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

> +int vgic_v2_probe(const struct gic_kvm_info *info);

>  int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,

>  			     enum vgic_type);

>  

> @@ -62,6 +65,7 @@ void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr);

>  void vgic_v3_set_underflow(struct kvm_vcpu *vcpu);

>  void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

>  void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);

> +int vgic_v3_probe(const struct gic_kvm_info *info);

>  int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);

>  #else

>  static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)

> @@ -95,6 +99,11 @@ void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)

>  {

>  }

>  

> +static inline int vgic_v3_probe(const struct gic_kvm_info *info)

> +{

> +	return -ENODEV;

> +}

> +

>  static inline int vgic_register_redist_iodevs(struct kvm *kvm,

>  					      gpa_t dist_base_address)

>  {

> -- 

> 2.8.2

> 


Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>


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diff mbox

Patch

diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
index 3689b9b..393489f 100644
--- a/include/kvm/vgic/vgic.h
+++ b/include/kvm/vgic/vgic.h
@@ -195,6 +195,7 @@  struct vgic_cpu {
 };
 
 int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
+int kvm_vgic_hyp_init(void);
 
 int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 			bool level);
diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
new file mode 100644
index 0000000..4523beb
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -0,0 +1,123 @@ 
+/*
+ * Copyright (C) 2015, 2016 ARM Ltd.
+ *
+ * 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/uaccess.h>
+#include <linux/interrupt.h>
+#include <linux/cpu.h>
+#include <linux/kvm_host.h>
+#include <kvm/arm_vgic.h>
+#include <asm/kvm_mmu.h>
+#include "vgic.h"
+
+/* GENERIC PROBE */
+
+static void vgic_init_maintenance_interrupt(void *info)
+{
+	enable_percpu_irq(kvm_vgic_global_state.maint_irq, 0);
+}
+
+static int vgic_cpu_notify(struct notifier_block *self,
+			   unsigned long action, void *cpu)
+{
+	switch (action) {
+	case CPU_STARTING:
+	case CPU_STARTING_FROZEN:
+		vgic_init_maintenance_interrupt(NULL);
+		break;
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		disable_percpu_irq(kvm_vgic_global_state.maint_irq);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block vgic_cpu_nb = {
+	.notifier_call = vgic_cpu_notify,
+};
+
+static irqreturn_t vgic_maintenance_handler(int irq, void *data)
+{
+	/*
+	 * We cannot rely on the vgic maintenance interrupt to be
+	 * delivered synchronously. This means we can only use it to
+	 * exit the VM, and we perform the handling of EOIed
+	 * interrupts on the exit path (see vgic_process_maintenance).
+	 */
+	return IRQ_HANDLED;
+}
+
+/**
+ * kvm_vgic_hyp_init: populates the kvm_vgic_global_state variable
+ * according to the host GIC model. Accordingly calls either
+ * vgic_v2/v3_probe which registers the KVM_DEVICE that can be
+ * instantiated by a guest later on .
+ */
+int kvm_vgic_hyp_init(void)
+{
+	const struct gic_kvm_info *gic_kvm_info;
+	int ret;
+
+	gic_kvm_info = gic_get_kvm_info();
+	if (!gic_kvm_info)
+		return -ENODEV;
+
+	if (!gic_kvm_info->maint_irq) {
+		kvm_err("No vgic maintenance irq\n");
+		return -ENXIO;
+	}
+
+	switch (gic_kvm_info->type) {
+	case GIC_V2:
+		ret = vgic_v2_probe(gic_kvm_info);
+		break;
+	case GIC_V3:
+		ret = vgic_v3_probe(gic_kvm_info);
+		break;
+	default:
+		ret = -ENODEV;
+	};
+
+	if (ret)
+		return ret;
+
+	kvm_vgic_global_state.maint_irq = gic_kvm_info->maint_irq;
+	ret = request_percpu_irq(kvm_vgic_global_state.maint_irq,
+				 vgic_maintenance_handler,
+				 "vgic", kvm_get_running_vcpus());
+	if (ret) {
+		kvm_err("Cannot register interrupt %d\n",
+			kvm_vgic_global_state.maint_irq);
+		return ret;
+	}
+
+	ret = __register_cpu_notifier(&vgic_cpu_nb);
+	if (ret) {
+		kvm_err("Cannot register vgic CPU notifier\n");
+		goto out_free_irq;
+	}
+
+	on_each_cpu(vgic_init_maintenance_interrupt, NULL, 1);
+
+	kvm_info("vgic interrupt IRQ%d\n", kvm_vgic_global_state.maint_irq);
+	return 0;
+
+out_free_irq:
+	free_percpu_irq(kvm_vgic_global_state.maint_irq,
+			kvm_get_running_vcpus());
+	return ret;
+}
diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index d943059..09777c8 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -17,6 +17,8 @@ 
 #include <linux/irqchip/arm-gic.h>
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
+#include <kvm/arm_vgic.h>
+#include <asm/kvm_mmu.h>
 
 #include "vgic.h"
 
@@ -203,3 +205,65 @@  void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 	vmcrp->pmr  = (vmcr & GICH_VMCR_PRIMASK_MASK) >>
 			GICH_VMCR_PRIMASK_SHIFT;
 }
+
+/**
+ * vgic_v2_probe - probe for a GICv2 compatible interrupt controller in DT
+ * @node:	pointer to the DT node
+ *
+ * Returns 0 if a GICv2 has been found, returns an error code otherwise
+ */
+int vgic_v2_probe(const struct gic_kvm_info *info)
+{
+	int ret;
+	u32 vtr;
+
+	if (!info->vctrl.start) {
+		kvm_err("GICH not present in the firmware table\n");
+		return -ENXIO;
+	}
+
+	if (!PAGE_ALIGNED(info->vcpu.start)) {
+		kvm_err("GICV physical address 0x%llx not page aligned\n",
+			(unsigned long long)info->vcpu.start);
+		return -ENXIO;
+	}
+
+	if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {
+		kvm_err("GICV size 0x%llx not a multiple of page size 0x%lx\n",
+			(unsigned long long)resource_size(&info->vcpu),
+			PAGE_SIZE);
+		return -ENXIO;
+	}
+
+	kvm_vgic_global_state.vctrl_base = ioremap(info->vctrl.start,
+						   resource_size(&info->vctrl));
+	if (!kvm_vgic_global_state.vctrl_base) {
+		kvm_err("Cannot ioremap GICH\n");
+		return -ENOMEM;
+	}
+
+	vtr = readl_relaxed(kvm_vgic_global_state.vctrl_base + GICH_VTR);
+	kvm_vgic_global_state.nr_lr = (vtr & 0x3f) + 1;
+
+	ret = create_hyp_io_mappings(kvm_vgic_global_state.vctrl_base,
+				     kvm_vgic_global_state.vctrl_base +
+					 resource_size(&info->vctrl),
+				     info->vctrl.start);
+
+	if (ret) {
+		kvm_err("Cannot map VCTRL into hyp\n");
+		iounmap(kvm_vgic_global_state.vctrl_base);
+		return ret;
+	}
+
+	kvm_vgic_global_state.can_emulate_gicv2 = true;
+	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
+
+	kvm_vgic_global_state.vcpu_base = info->vcpu.start;
+	kvm_vgic_global_state.type = VGIC_V2;
+	kvm_vgic_global_state.max_gic_vcpus = VGIC_V2_MAX_CPUS;
+
+	kvm_info("vgic-v2@%llx\n", info->vctrl.start);
+
+	return 0;
+}
diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index 8548297..de0e8e0 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -15,6 +15,9 @@ 
 #include <linux/irqchip/arm-gic-v3.h>
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
+#include <kvm/arm_vgic.h>
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_asm.h>
 
 #include "vgic.h"
 
@@ -182,3 +185,49 @@  void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcrp)
 	vmcrp->bpr  = (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
 	vmcrp->pmr  = (vmcr & ICH_VMCR_PMR_MASK) >> ICH_VMCR_PMR_SHIFT;
 }
+
+/**
+ * vgic_v3_probe - probe for a GICv3 compatible interrupt controller in DT
+ * @node:	pointer to the DT node
+ *
+ * Returns 0 if a GICv3 has been found, returns an error code otherwise
+ */
+int vgic_v3_probe(const struct gic_kvm_info *info)
+{
+	u32 ich_vtr_el2 = kvm_call_hyp(__vgic_v3_get_ich_vtr_el2);
+
+	/*
+	 * The ListRegs field is 5 bits, but there is a architectural
+	 * maximum of 16 list registers. Just ignore bit 4...
+	 */
+	kvm_vgic_global_state.nr_lr = (ich_vtr_el2 & 0xf) + 1;
+	kvm_vgic_global_state.can_emulate_gicv2 = false;
+
+	if (!info->vcpu.start) {
+		kvm_info("GICv3: no GICV resource entry\n");
+		kvm_vgic_global_state.vcpu_base = 0;
+	} else if (!PAGE_ALIGNED(info->vcpu.start)) {
+		pr_warn("GICV physical address 0x%llx not page aligned\n",
+			(unsigned long long)info->vcpu.start);
+		kvm_vgic_global_state.vcpu_base = 0;
+	} else if (!PAGE_ALIGNED(resource_size(&info->vcpu))) {
+		pr_warn("GICV size 0x%llx not a multiple of page size 0x%lx\n",
+			(unsigned long long)resource_size(&info->vcpu),
+			PAGE_SIZE);
+		kvm_vgic_global_state.vcpu_base = 0;
+	} else {
+		kvm_vgic_global_state.vcpu_base = info->vcpu.start;
+		kvm_vgic_global_state.can_emulate_gicv2 = true;
+		kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
+		kvm_info("vgic-v2@%llx\n", info->vcpu.start);
+	}
+	if (kvm_vgic_global_state.vcpu_base == 0)
+		kvm_info("disabling GICv2 emulation\n");
+	kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V3);
+
+	kvm_vgic_global_state.vctrl_base = NULL;
+	kvm_vgic_global_state.type = VGIC_V3;
+	kvm_vgic_global_state.max_gic_vcpus = VGIC_V3_MAX_CPUS;
+
+	return 0;
+}
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index de9dc71..f4244b6 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -16,6 +16,8 @@ 
 #ifndef __KVM_ARM_VGIC_NEW_H__
 #define __KVM_ARM_VGIC_NEW_H__
 
+#include <linux/irqchip/arm-gic-common.h>
+
 #define PRODUCT_ID_KVM		0x4b	/* ASCII code K */
 #define IMPLEMENTER_ARM		0x43b
 
@@ -51,6 +53,7 @@  int vgic_v2_cpuif_uaccess(struct kvm_vcpu *vcpu, bool is_write,
 			  int offset, u32 *val);
 void vgic_v2_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 void vgic_v2_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
+int vgic_v2_probe(const struct gic_kvm_info *info);
 int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
 			     enum vgic_type);
 
@@ -62,6 +65,7 @@  void vgic_v3_clear_lr(struct kvm_vcpu *vcpu, int lr);
 void vgic_v3_set_underflow(struct kvm_vcpu *vcpu);
 void vgic_v3_set_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
 void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr);
+int vgic_v3_probe(const struct gic_kvm_info *info);
 int vgic_register_redist_iodevs(struct kvm *kvm, gpa_t dist_base_address);
 #else
 static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
@@ -95,6 +99,11 @@  void vgic_v3_get_vmcr(struct kvm_vcpu *vcpu, struct vgic_vmcr *vmcr)
 {
 }
 
+static inline int vgic_v3_probe(const struct gic_kvm_info *info)
+{
+	return -ENODEV;
+}
+
 static inline int vgic_register_redist_iodevs(struct kvm *kvm,
 					      gpa_t dist_base_address)
 {