Re: [PATCH v9 10/17] KVM: arm64: introduce new KVM ITS device

[Marc Zyngier <marc.zyngier@arm.com>]

On 13/07/16 02:59, Andre Przywara wrote:
> Introduce a new KVM device that represents an ARM Interrupt Translation
> Service (ITS) controller. Since there can be multiple of this per guest,
> we can't piggy back on the existing GICv3 distributor device, but create
> a new type of KVM device.
> On the KVM_CREATE_DEVICE ioctl we allocate and initialize the ITS data
> structure and store the pointer in the kvm_device data.
> Upon an explicit init ioctl from userland (after having setup the MMIO
> address) we register the handlers with the kvm_io_bus framework.
> Any reference to an ITS thus has to go via this interface.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  Documentation/virtual/kvm/devices/arm-vgic.txt |  25 +++--
>  arch/arm/kvm/arm.c                             |   1 +
>  arch/arm64/include/uapi/asm/kvm.h              |   2 +
>  include/kvm/arm_vgic.h                         |   3 +
>  include/uapi/linux/kvm.h                       |   2 +
>  virt/kvm/arm/vgic/vgic-its.c                   | 144 ++++++++++++++++++++++++-
>  virt/kvm/arm/vgic/vgic-kvm-device.c            |   7 +-
>  virt/kvm/arm/vgic/vgic-mmio-v3.c               |   2 +-
>  virt/kvm/arm/vgic/vgic.h                       |   8 ++
>  9 files changed, 183 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt
> index 59541d4..89182f8 100644
> --- a/Documentation/virtual/kvm/devices/arm-vgic.txt
> +++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
> @@ -4,16 +4,22 @@ ARM Virtual Generic Interrupt Controller (VGIC)
>  Device types supported:
>    KVM_DEV_TYPE_ARM_VGIC_V2     ARM Generic Interrupt Controller v2.0
>    KVM_DEV_TYPE_ARM_VGIC_V3     ARM Generic Interrupt Controller v3.0
> +  KVM_DEV_TYPE_ARM_VGIC_ITS    ARM Interrupt Translation Service Controller
>  
> -Only one VGIC instance may be instantiated through either this API or the
> -legacy KVM_CREATE_IRQCHIP api.  The created VGIC will act as the VM interrupt
> -controller, requiring emulated user-space devices to inject interrupts to the
> -VGIC instead of directly to CPUs.
> +Only one VGIC instance of the V2/V3 types above may be instantiated through
> +either this API or the legacy KVM_CREATE_IRQCHIP api.  The created VGIC will
> +act as the VM interrupt controller, requiring emulated user-space devices to
> +inject interrupts to the VGIC instead of directly to CPUs.
>  
>  Creating a guest GICv3 device requires a host GICv3 as well.
>  GICv3 implementations with hardware compatibility support allow a guest GICv2
>  as well.
>  
> +Creating a virtual ITS controller requires a host GICv3 (but does not depend
> +on having physical ITS controllers).
> +There can be multiple ITS controllers per guest, each of them has to have
> +a separate, non-overlapping MMIO region.
> +
>  Groups:
>    KVM_DEV_ARM_VGIC_GRP_ADDR
>    Attributes:
> @@ -39,6 +45,13 @@ 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.
> +      Only valid for KVM_DEV_TYPE_ARM_VGIC_ITS.
> +      This address needs to be 64K aligned and the region covers 128K.
>  
>    KVM_DEV_ARM_VGIC_GRP_DIST_REGS
>    Attributes:
> @@ -109,8 +122,8 @@ Groups:
>    KVM_DEV_ARM_VGIC_GRP_CTRL
>    Attributes:
>      KVM_DEV_ARM_VGIC_CTRL_INIT
> -      request the initialization of the VGIC, no additional parameter in
> -      kvm_device_attr.addr.
> +      request the initialization of the VGIC or ITS, no additional parameter
> +      in kvm_device_attr.addr.
>    Errors:
>      -ENXIO: VGIC not properly configured as required prior to calling
>       this attribute
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 557e390..0d5c255 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -20,6 +20,7 @@
>  #include <linux/errno.h>
>  #include <linux/err.h>
>  #include <linux/kvm_host.h>
> +#include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/vmalloc.h>
>  #include <linux/fs.h>
> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
> index f209ea1..3051f86 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_ITS_ADDR_TYPE		4
>  
>  #define KVM_VGIC_V3_DIST_SIZE		SZ_64K
>  #define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)
> +#define KVM_VGIC_V3_ITS_SIZE		(2 * 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/arm_vgic.h b/include/kvm/arm_vgic.h
> index 685f339..8609fac 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -134,6 +134,7 @@ struct vgic_its {
>  	gpa_t			vgic_its_base;
>  
>  	bool			enabled;
> +	bool			initialized;
>  	struct vgic_io_device	iodev;
>  };
>  
> @@ -167,6 +168,8 @@ struct vgic_dist {
>  
>  	struct vgic_io_device	dist_iodev;
>  
> +	bool			has_its;
> +
>  	/*
>  	 * Contains the attributes and gpa of the LPI configuration table.
>  	 * Since we report GICR_TYPER.CommonLPIAff as 0b00, we can share
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 7de96f5..d8c4c32 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -1077,6 +1077,8 @@ enum kvm_device_type {
>  #define KVM_DEV_TYPE_FLIC		KVM_DEV_TYPE_FLIC
>  	KVM_DEV_TYPE_ARM_VGIC_V3,
>  #define KVM_DEV_TYPE_ARM_VGIC_V3	KVM_DEV_TYPE_ARM_VGIC_V3
> +	KVM_DEV_TYPE_ARM_VGIC_ITS,
> +#define KVM_DEV_TYPE_ARM_VGIC_ITS	KVM_DEV_TYPE_ARM_VGIC_ITS
>  	KVM_DEV_TYPE_MAX,
>  };
>  
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index 06ad94d..393ad3a 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -21,6 +21,7 @@
>  #include <linux/kvm.h>
>  #include <linux/kvm_host.h>
>  #include <linux/interrupt.h>
> +#include <linux/uaccess.h>
>  
>  #include <linux/irqchip/arm-gic-v3.h>
>  
> @@ -79,7 +80,7 @@ static struct vgic_register_region its_registers[] = {
>  		VGIC_ACCESS_32bit),
>  };
>  
> -int vgic_its_register(struct kvm *kvm, struct vgic_its *its)
> +static int vgic_its_register(struct kvm *kvm, struct vgic_its *its)

Please move this hunk to the previous patch...

>  {
>  	struct vgic_io_device *iodev = &its->iodev;
>  	int ret;
> @@ -93,8 +94,147 @@ int vgic_its_register(struct kvm *kvm, struct vgic_its *its)
>  	iodev->its = its;
>  	mutex_lock(&kvm->slots_lock);
>  	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, iodev->base_addr,
> -				      SZ_64K, &iodev->dev);
> +				      KVM_VGIC_V3_ITS_SIZE, &iodev->dev);

as well as this one.

>  	mutex_unlock(&kvm->slots_lock);
>  
>  	return ret;
>  }
> +
> +static int vgic_its_create(struct kvm_device *dev, u32 type)
> +{
> +	struct vgic_its *its;
> +
> +	if (type != KVM_DEV_TYPE_ARM_VGIC_ITS)
> +		return -ENODEV;
> +
> +	its = kzalloc(sizeof(struct vgic_its), GFP_KERNEL);
> +	if (!its)
> +		return -ENOMEM;
> +
> +	its->vgic_its_base = VGIC_ADDR_UNDEF;
> +
> +	dev->kvm->arch.vgic.has_its = true;
> +	its->initialized = false;
> +	its->enabled = false;
> +
> +	dev->private = its;
> +
> +	return 0;
> +}
> +
> +static void vgic_its_destroy(struct kvm_device *kvm_dev)
> +{
> +	struct vgic_its *its = kvm_dev->private;
> +
> +	kfree(its);
> +}
> +
> +static int vgic_its_has_attr(struct kvm_device *dev,
> +			     struct kvm_device_attr *attr)
> +{
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_ADDR:
> +		switch (attr->attr) {
> +		case KVM_VGIC_ITS_ADDR_TYPE:
> +			return 0;
> +		}
> +		break;
> +	case KVM_DEV_ARM_VGIC_GRP_CTRL:
> +		switch (attr->attr) {
> +		case KVM_DEV_ARM_VGIC_CTRL_INIT:
> +			return 0;
> +		}
> +		break;
> +	}
> +	return -ENXIO;
> +}
> +
> +static int vgic_its_set_attr(struct kvm_device *dev,
> +			     struct kvm_device_attr *attr)
> +{
> +	struct vgic_its *its = dev->private;
> +	int ret;
> +
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
> +		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> +		unsigned long type = (unsigned long)attr->attr;
> +		u64 addr;
> +
> +		if (type != KVM_VGIC_ITS_ADDR_TYPE)
> +			return -ENODEV;
> +
> +		if (its->initialized)
> +			return -EBUSY;
> +
> +		if (copy_from_user(&addr, uaddr, sizeof(addr)))
> +			return -EFAULT;
> +
> +		ret = vgic_check_ioaddr(dev->kvm, &its->vgic_its_base,
> +					addr, SZ_64K);

Shouldn't that be the ITS size (128kB)?

> +		if (ret)
> +			return ret;
> +
> +		its->vgic_its_base = addr;
> +
> +		return 0;
> +	}
> +	case KVM_DEV_ARM_VGIC_GRP_CTRL:
> +		switch (attr->attr) {
> +		case KVM_DEV_ARM_VGIC_CTRL_INIT:
> +			if (its->initialized)
> +				return 0;
> +
> +			if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
> +				return -ENXIO;
> +
> +			ret = vgic_its_register(dev->kvm, its);
> +			if (ret)
> +				return ret;
> +
> +			its->initialized = true;
> +			return 0;

Can't you move all of that into vgic_its_register? That'd be a lot cleaner.

> +		}
> +		break;
> +	}
> +	return -ENXIO;
> +}
> +
> +static int vgic_its_get_attr(struct kvm_device *dev,
> +			     struct kvm_device_attr *attr)
> +{
> +	switch (attr->group) {
> +	case KVM_DEV_ARM_VGIC_GRP_ADDR: {
> +		struct vgic_its *its = dev->private;
> +		u64 addr = its->vgic_its_base;
> +		u64 __user *uaddr = (u64 __user *)(long)attr->addr;
> +		unsigned long type = (unsigned long)attr->attr;
> +
> +		if (type != KVM_VGIC_ITS_ADDR_TYPE)
> +			return -ENODEV;
> +
> +		if (copy_to_user(uaddr, &addr, sizeof(addr)))
> +			return -EFAULT;
> +		break;
> +	default:
> +		return -ENXIO;
> +	}
> +	}
> +
> +	return 0;
> +}
> +
> +struct kvm_device_ops kvm_arm_vgic_its_ops = {

Should be static.

> +	.name = "kvm-arm-vgic-its",
> +	.create = vgic_its_create,
> +	.destroy = vgic_its_destroy,
> +	.set_attr = vgic_its_set_attr,
> +	.get_attr = vgic_its_get_attr,
> +	.has_attr = vgic_its_has_attr,
> +};
> +
> +int kvm_vgic_register_its_device(void)
> +{
> +	return kvm_register_device_ops(&kvm_arm_vgic_its_ops,
> +				       KVM_DEV_TYPE_ARM_VGIC_ITS);
> +}
> diff --git a/virt/kvm/arm/vgic/vgic-kvm-device.c b/virt/kvm/arm/vgic/vgic-kvm-device.c
> index 2f24f13..1813f93 100644
> --- a/virt/kvm/arm/vgic/vgic-kvm-device.c
> +++ b/virt/kvm/arm/vgic/vgic-kvm-device.c
> @@ -21,8 +21,8 @@
>  
>  /* common helpers */
>  
> -static int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
> -			     phys_addr_t addr, phys_addr_t alignment)
> +int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
> +		      phys_addr_t addr, phys_addr_t alignment)
>  {
>  	if (addr & ~KVM_PHYS_MASK)
>  		return -E2BIG;
> @@ -223,6 +223,9 @@ int kvm_register_vgic_device(unsigned long type)
>  	case KVM_DEV_TYPE_ARM_VGIC_V3:
>  		ret = kvm_register_device_ops(&kvm_arm_vgic_v3_ops,
>  					      KVM_DEV_TYPE_ARM_VGIC_V3);
> +		if (ret)
> +			break;
> +		ret = kvm_vgic_register_its_device();
>  		break;
>  #endif
>  	}
> diff --git a/virt/kvm/arm/vgic/vgic-mmio-v3.c b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> index 4169e22..6cb52dd 100644
> --- a/virt/kvm/arm/vgic/vgic-mmio-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-mmio-v3.c
> @@ -49,7 +49,7 @@ bool vgic_has_its(struct kvm *kvm)
>  	if (dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3)
>  		return false;
>  
> -	return false;
> +	return dist->has_its;
>  }
>  
>  static unsigned long vgic_mmio_read_v3_misc(struct kvm_vcpu *vcpu,
> diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
> index 31807c1..9dc7207 100644
> --- a/virt/kvm/arm/vgic/vgic.h
> +++ b/virt/kvm/arm/vgic/vgic.h
> @@ -42,6 +42,9 @@ void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq);
>  bool vgic_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq);
>  void vgic_kick_vcpus(struct kvm *kvm);
>  
> +int vgic_check_ioaddr(struct kvm *kvm, phys_addr_t *ioaddr,
> +		      phys_addr_t addr, phys_addr_t alignment);
> +
>  void vgic_v2_process_maintenance(struct kvm_vcpu *vcpu);
>  void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu);
>  void vgic_v2_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr);
> @@ -73,6 +76,7 @@ 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);
> +int kvm_vgic_register_its_device(void);
>  #else
>  static inline void vgic_v3_process_maintenance(struct kvm_vcpu *vcpu)
>  {
> @@ -130,6 +134,10 @@ static inline bool vgic_has_its(struct kvm *kvm)
>  	return false;
>  }
>  
> +static inline int kvm_vgic_register_its_device(void)
> +{
> +	return -ENODEV;
> +}
>  #endif
>  
>  int kvm_register_vgic_device(unsigned long type);
> 

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...