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

[Chalamarla, Tirumalesh]

On 5/9/16, 8:47 AM, "Marc Zyngier" <marc.zyngier at arm.com> wrote:

>On 05/05/16 19:08, Chalamarla, Tirumalesh wrote:
>> 
>> 
>> 
>> 
>> 
>> On 3/25/16, 7:14 PM, "kvmarm-bounces at lists.cs.columbia.edu on behalf of Andre Przywara" <kvmarm-bounces at lists.cs.columbia.edu on behalf of andre.przywara at arm.com> 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 <andre.przywara at arm.com>
>>> ---
>>> 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
>>> +      does not support the ITS, the call returns -ENODEV.
>>> +      This memory is solely for the guest to access the ITS control
>>> +      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.
>>>
>>>   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);
>>> +
>>> #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)
>>> +{
>>> +	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;
>> 
>> Should there be a check based on number of vcpus? 
>
>Why would the number of vcpus influence the size of the ITS?

does the re-distributor per VCPU thing? I think its worth to add a check for re distributor size. 
>
>Thanks,
>
>	M.
>-- 
>Jazz is not dead. It just smells funny...