Subject: [PATCH v4 03/12] KVM: arm64: Introduce new MMIO region for the ITS base address

From: [email-masked] (Eric Auger)
Date: Tue, 5 Apr 2016 14:47:51 +0200

Hi Andre,
On 04/03/2016 12:08 PM, Christoffer Dall wrote:
> On Sat, Mar 26, 2016 at 02:14:01AM +0000, Andre Przywara wrote:
>> The ARM GICv3 ITS controller requires a separate register frame to
>> cover ITS specific registers. Add a new VGIC address type and store
>> the address in a field in the vgic_dist structure.
>> Provide a function to check whether userland has provided the address,
>> so ITS functionality can be guarded by that check.
>>
>> Signed-off-by: Andre Przywara <[email-masked]>
>> ---
>>  Documentation/virtual/kvm/devices/arm-vgic.txt |  9 +++++++++
>>  arch/arm64/include/uapi/asm/kvm.h              |  2 ++
>>  include/kvm/vgic/vgic.h                        |  5 +++++
>>  virt/kvm/arm/vgic/vgic.c                       | 10 ++++++++++
>>  virt/kvm/arm/vgic/vgic_init.c                  |  1 +
>>  virt/kvm/arm/vgic/vgic_kvm_device.c            |  7 +++++++
>>  6 files changed, 34 insertions(+)
>>
>> diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt
>> index 59541d4..087e2d9 100644
>> --- a/Documentation/virtual/kvm/devices/arm-vgic.txt
>> +++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
>> @@ -39,6 +39,15 @@ 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
> 
> s/optional, if/optional. If/
> 
>> +      does not support the ITS, the call returns -ENODEV.
>> +      This memory is solely for the guest to access the ITS control
> 
> s/memory/address region/ ?
> 
>> +      registers and does not cover the ITS translation register.
>> +      Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
>> +      This address needs to be 64K aligned and the region covers 64 KByte.
> 
> s/KByte/KBytes/
> ...or you could you 64K both places in this line.
> 
>>  
>>    KVM_DEV_ARM_VGIC_GRP_DIST_REGS
>>    Attributes:
>> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
>> index f209ea1..c2b257d 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_V3_ADDR_TYPE_ITS	4
>>  
>>  #define KVM_VGIC_V3_DIST_SIZE		SZ_64K
>>  #define KVM_VGIC_V3_REDIST_SIZE		(2 * SZ_64K)
>> +#define KVM_VGIC_V3_ITS_SIZE		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/vgic/vgic.h b/include/kvm/vgic/vgic.h
>> index 7c1d145..11344e6 100644
>> --- a/include/kvm/vgic/vgic.h
>> +++ b/include/kvm/vgic/vgic.h
>> @@ -135,6 +135,9 @@ struct vgic_dist {
>>  		gpa_t			vgic_redist_base;
>>  	};
>>  
>> +	/* The base address of the ITS control register frame */
>> +	gpa_t			vgic_its_base;
>> +
>>  	/* distributor enabled */
>>  	u32			enabled;
>>  
>> @@ -253,4 +256,6 @@ static inline int kvm_vgic_get_max_vcpus(void)
>>  	return kvm_vgic_global_state.max_gic_vcpus;
>>  }
>>  
>> +bool vgic_has_its(struct kvm *kvm);
is it mandated to expose this function outside of the vgic subsystem?
why not declaring it in /virt/kvm/arm/vgic/vgic.h?
>> +
>>  #endif /* __ASM_ARM_KVM_VGIC_VGIC_H */
>> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
>> index 65395af..1de2478 100644
>> --- a/virt/kvm/arm/vgic/vgic.c
>> +++ b/virt/kvm/arm/vgic/vgic.c
>> @@ -612,3 +612,13 @@ bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, u32 intid)
>>  
>>  	return map_is_active;
>>  }
>> +
>> +bool vgic_has_its(struct kvm *kvm)
I would implement this function vgic_init.c or vgic_kvm_device.c leaving
vgic.c for pure vgic state mgt.

Eric
>> +{
>> +	struct vgic_dist *dist = &kvm->arch.vgic;
>> +
>> +	if (dist->vgic_model != KVM_DEV_TYPE_ARM_VGIC_V3)
>> +		return false;
>> +
>> +	return !IS_VGIC_ADDR_UNDEF(dist->vgic_its_base);
>> +}
>> diff --git a/virt/kvm/arm/vgic/vgic_init.c b/virt/kvm/arm/vgic/vgic_init.c
>> index ac655b5..2301e03 100644
>> --- a/virt/kvm/arm/vgic/vgic_init.c
>> +++ b/virt/kvm/arm/vgic/vgic_init.c
>> @@ -132,6 +132,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
>>  	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
>>  	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
>>  	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
>> +	kvm->arch.vgic.vgic_its_base = VGIC_ADDR_UNDEF;
>>  
>>  out_unlock:
>>  	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
>> diff --git a/virt/kvm/arm/vgic/vgic_kvm_device.c b/virt/kvm/arm/vgic/vgic_kvm_device.c
>> index 7f78a16..3ec2ac3 100644
>> --- a/virt/kvm/arm/vgic/vgic_kvm_device.c
>> +++ b/virt/kvm/arm/vgic/vgic_kvm_device.c
>> @@ -109,6 +109,12 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
>>  		block_size = KVM_VGIC_V3_REDIST_SIZE;
>>  		alignment = SZ_64K;
>>  		break;
>> +	case KVM_VGIC_V3_ADDR_TYPE_ITS:
>> +		type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
>> +		addr_ptr = &vgic->vgic_its_base;
>> +		block_size = KVM_VGIC_V3_ITS_SIZE;
>> +		alignment = SZ_64K;
>> +		break;
>>  #endif
>>  	default:
>>  		r = -ENODEV;
>> @@ -495,6 +501,7 @@ static int vgic_v3_has_attr(struct kvm_device *dev,
>>  		switch (attr->attr) {
>>  		case KVM_VGIC_V3_ADDR_TYPE_DIST:
>>  		case KVM_VGIC_V3_ADDR_TYPE_REDIST:
>> +		case KVM_VGIC_V3_ADDR_TYPE_ITS:
>>  			return 0;
>>  		}
>>  		break;
>> -- 
>> 2.7.3
>>