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KVM: ARM: Introduce KVM_ARM_SET_DEVICE_ADDR ioctl

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On ARM some bits are specific to the model being emulated for the guest and
user space needs a way to tell the kernel about those bits.  An example is mmio
device base addresses, where KVM must know the base address for a given device
to properly emulate mmio accesses within a certain address range or directly
map a device with virtualiation extensions into the guest address space.

We make this API ARM-specific as we haven't yet reached a consensus for a
generic API for all KVM architectures that will allow us to do something like
this.

Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Christoffer Dall
2013-01-23 13:18:04 -05:00
committed by Marc Zyngier
parent a96ab03917
commit 3401d54696
4 changed files with 80 additions and 1 deletions
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37
Documentation/virtual/kvm/api.txt
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@@ -2210,6 +2210,43 @@ This ioctl returns the guest registers that are supported for the
KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
4.80 KVM_ARM_SET_DEVICE_ADDR
Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
Architectures: arm
Type: vm ioctl
Parameters: struct kvm_arm_device_address (in)
Returns: 0 on success, -1 on error
Errors:
ENODEV: The device id is unknown
ENXIO: Device not supported on current system
EEXIST: Address already set
E2BIG: Address outside guest physical address space
struct kvm_arm_device_addr {
__u64 id;
__u64 addr;
};
Specify a device address in the guest's physical address space where guests
can access emulated or directly exposed devices, which the host kernel needs
to know about. The id field is an architecture specific identifier for a
specific device.
ARM divides the id field into two parts, a device id and an address type id
specific to the individual device.
 bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 |
field: | 0x00000000 | device id | addr type id |
ARM currently only require this when using the in-kernel GIC support for the
hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 as the device id. When
setting the base address for the guest's mapping of the VGIC virtual CPU
and distributor interface, the ioctl must be called after calling
KVM_CREATE_IRQCHIP, but before calling KVM_RUN on any of the VCPUs. Calling
this ioctl twice for any of the base addresses will return -EEXIST.
5. The kvm_run structure
------------------------