[RFC 01/13] KVM: arm/arm64: Add vITS save/restore API documentation

[Peter Maydell]

On 12 January 2017 at 15:56, Eric Auger <eric.auger at redhat.com> wrote:
> Add description for how to access vITS registers and how to flush/restore
> vITS tables into/from memory
>
> Signed-off-by: Eric Auger <eric.auger at redhat.com>
> ---
>  Documentation/virtual/kvm/devices/arm-vgic-its.txt | 70 ++++++++++++++++++++++
>  1 file changed, 70 insertions(+)
>
> diff --git a/Documentation/virtual/kvm/devices/arm-vgic-its.txt b/Documentation/virtual/kvm/devices/arm-vgic-its.txt
> index 6081a5b..bd74613 100644
> --- a/Documentation/virtual/kvm/devices/arm-vgic-its.txt
> +++ b/Documentation/virtual/kvm/devices/arm-vgic-its.txt
> @@ -36,3 +36,73 @@ Groups:
>      -ENXIO:  ITS not properly configured as required prior to setting
>               this attribute
>      -ENOMEM: Memory shortage when allocating ITS internal data
> +
> +  KVM_DEV_ARM_VGIC_GRP_ITS_REGS
> +  Attributes:
> +      The attr field of kvm_device_attr encodes the offset of the
> +      ITS register, relative to the ITS control frame base address
> +      (ITS_base).
> +
> +      kvm_device_attr.addr points to a __u64 value whatever the width
> +      of the addressed register (32/64 bits).
> +
> +      Writes to read-only registers are ignored by the kernel except
> +      for a single register, GITS_READR. Normally this register is RO
> +      but it needs to be restored otherwise commands in the queue will
> +      be re-executed after CWRITER setting.

Dumb question -- is it possible/sensible to process the command
queue rather than migrating a list of outstanding commands?

thanks
-- PMM