[PATCH v7 10/17] KVM: arm64: introduce new KVM ITS device
Auger Eric
eric.auger at redhat.com
Mon Jul 4 07:27:32 PDT 2016
Andre,
On 04/07/2016 16:05, Andre Przywara wrote:
> Hi,
>
> On 04/07/16 10:00, Auger Eric wrote:
>> Hi Andre,
>>
>> On 28/06/2016 14:32, 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 at 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/vgic/vgic.h | 1 +
>>> include/uapi/linux/kvm.h | 2 +
>>> virt/kvm/arm/vgic/vgic-its.c | 127 ++++++++++++++++++++++++-
>>> 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, 165 insertions(+), 10 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 a268c85..f4a953e 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..f8c257b 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 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 949a0e1..8cec203 100644
>>> --- a/include/kvm/vgic/vgic.h
>>> +++ b/include/kvm/vgic/vgic.h
>>> @@ -159,6 +159,7 @@ struct vgic_dist {
>>>
>>> struct vgic_io_device dist_iodev;
>>>
>>> + bool has_its;
>>> /*
>>> * Contains the address 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 ab8d244..62d7484 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>
>>>
>>> @@ -80,7 +81,7 @@ static struct vgic_register_region its_registers[] = {
>>> VGIC_ACCESS_32bit),
>>> };
>>>
>>> -int vits_register(struct kvm *kvm, struct vgic_its *its)
>>> +static int vits_register(struct kvm *kvm, struct vgic_its *its)
>>> {
>>> struct vgic_io_device *iodev = &its->iodev;
>>> int ret;
>>> @@ -98,3 +99,127 @@ int vits_register(struct kvm *kvm, struct vgic_its *its)
>>>
>>> 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->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 (copy_from_user(&addr, uaddr, sizeof(addr)))
>>> + return -EFAULT;
>>> +
>>> + ret = vgic_check_ioaddr(dev->kvm, &its->vgic_its_base,
>>> + addr, SZ_64K);
>>> + 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:
>>> + return vits_register(dev->kvm, its);
>> This does not look homogeneous with the GICv2/3 code init sequence
>>
>> on vgic GICv2/v3 KVM_DEV_ARM_VGIC_GRP_CTRL/KVM_DEV_ARM_VGIC_CTRL_INIT
>> we call vgic_init/kvm_vgic_dist_init/kvm_vgic_vcpu_init.
>>
>> the kvm_vgic_map_resources was responsible for registering the iodevs.
>> this was called on kvm_vcpu_first_run_init.
>
> Which I think is something that we do for keeping compatibility with the
> older lazy VGIC init sequence only?
>
>> Here for ITS you propose to do the iodev registration on
>> KVM_DEV_ARM_VGIC_CTRL_INIT
>
> I think it's more logical to do it then. With CTRL_INIT userland
> signalizes that it's done with the setup, so we can setup everything.
>
>> From a QEMU integration point of view this means the init sequence used
>> for KVM GIC interrupt controllers cannot be reused for ITS and more
>> importantly this is not straightforward to have the proper sequence
>> ordering (hence the previously reported case).
>
> I am confused, can you please elaborate what the problem is?
> Or alternatively sketch what you ideally would the ITS init sequence to
> look like? I am totally open to any changes, just need to know what
> you/QEMU needs.
in QEMU the address setting is done on a so-called qemu
"machine_init_done_notifier", ie. a callback that is registered at ITS
device init, to be called once the virt machine code has executed. This
callback calls kvm_device_ioctl(kd->dev_fd, KVM_SET_DEVICE_ATTR, attr);
In case the userspace needs to explicitly "init" the ITS (actually ~
map_resources) this must happen after the KVM_SET_DEVICE_ATTR. So you
also must register a callback in the same way. However there is a
framework existing to register kvm device addresses but this does not
exist to set other attributes than device addresses.
This is feasible I think but this does not fit qemu nicely. So can't the
map_resources happen implicitly on the first VCPU run?
Thanks
Eric
>
> Cheers,
> Andre.
>
>
>> Why not offering a similar mechanism?
>>
>> Thanks
>>
>> Eric
>>
>>
>>
>>
>>
>>> + }
>>> + 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 = {
>>> + .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 5fcc33a..9bcffa6 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);
>>>
>>
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