On 19/03/18 09:20, Eric Auger wrote: > We introduce a new KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION attribute in > KVM_DEV_ARM_VGIC_GRP_ADDR group. It allows userspace to provide the > base address and size of a redistributor region > > Compared to KVM_VGIC_V3_ADDR_TYPE_REDIST, this new attribute allows > to declare several separate redistributor regions. > > So the whole redist space does not need to be contiguous anymore. > > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > --- > Documentation/virtual/kvm/devices/arm-vgic-v3.txt | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt > index 9293b45..2c0bedf 100644 > --- a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt > +++ b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt > @@ -27,6 +27,18 @@ Groups: > VCPU and all of the redistributor pages are contiguous. > Only valid for KVM_DEV_TYPE_ARM_VGIC_V3. > This address needs to be 64K aligned. > + > + KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION (rw, 64-bit) > + The attr field of kvm_device_attr encodes 3 values: > + bits: | 63 .... 52 | 51 .... 12 |11 - 0 > + values: | pfns | base | index > + - index encodes the unique redistibutor region index > + - base field encodes bits [51:12] the guest physical base address > + of the first redistributor in the region. There are two 64K pages > + for each VCPU and all of the redistributor pages are contiguous > + within the redistributor region. Why does base have to include bits [15:12] of the IPA? If it is 64kB aligned (as it should), these bits are guaranteed to be 0. This also avoid having to return -EINVAL in case of alignment problems. > + - pfns encodes the size of the region in 64kB pages. > + Only valid for KVM_DEV_TYPE_ARM_VGIC_V3. "pfns" a bit of an odd name, and is a bit unnatural. Why don't we instead encode the number of redistributors? You've already imposed that a redistributor has 2 64kB pages, so let's take advantage of this by saving yet another bit. You could dedicate a couple of these bits as a selector for the ITS version (v3, v4 or whatever comes after that, if ever...). Just make 0 the only valid version for the time being. > Errors: > -E2BIG: Address outside of addressable IPA range > -EINVAL: Incorrectly aligned address > Thanks, M. -- Jazz is not dead. It just smells funny...
