linux-stable/Documentation/virtual/kvm/devices/arm-vgic-its.txt
Christoffer Dall 7148480265 KVM: arm/arm64: Add VGICv3 save/restore API documentation
Factor out the GICv3 and ITS-specific documentation into a separate
documentation file.  Add description for how to access distributor,
redistributor, and CPU interface registers for GICv3 in this new file,
and add a group for accessing level triggered IRQ information for GICv3
as well.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
2016-09-08 12:53:00 +02:00

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ARM Virtual Interrupt Translation Service (ITS)
===============================================
Device types supported:
KVM_DEV_TYPE_ARM_VGIC_ITS ARM Interrupt Translation Service Controller
The ITS allows MSI(-X) interrupts to be injected into guests. This extension is
optional. Creating a virtual ITS controller also requires a host GICv3 (see
arm-vgic-v3.txt), 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:
KVM_VGIC_ITS_ADDR_TYPE (rw, 64-bit)
Base address in the guest physical address space of the GICv3 ITS
control register frame.
This address needs to be 64K aligned and the region covers 128K.
Errors:
-E2BIG: Address outside of addressable IPA range
-EINVAL: Incorrectly aligned address
-EEXIST: Address already configured
-EFAULT: Invalid user pointer for attr->addr.
-ENODEV: Incorrect attribute or the ITS is not supported.
KVM_DEV_ARM_VGIC_GRP_CTRL
Attributes:
KVM_DEV_ARM_VGIC_CTRL_INIT
request the initialization of the ITS, no additional parameter in
kvm_device_attr.addr.
Errors:
-ENXIO: ITS not properly configured as required prior to setting
this attribute
-ENOMEM: Memory shortage when allocating ITS internal data