KVM: arm/arm64: Document KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION

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 <[email protected]> Reviewed-by: Peter Maydell <[email protected]> Acked-by: Christoffer Dall <[email protected]> Signed-off-by: Marc Zyngier <[email protected]>
cail · May 25, 2018 · d6c77bd · d6c77bd
1 parent 9153ab7
commit d6c77bd
Showing 1 changed file with 28 additions and 2 deletions.
diff --git a/Documentation/virtual/kvm/devices/arm-vgic-v3.txt b/Documentation/virtual/kvm/devices/arm-vgic-v3.txt
@@ -27,16 +27,42 @@ 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 attribute data pointed to by kvm_device_attr.addr is a __u64 value:
+      bits:     | 63   ....  52  |  51   ....   16 | 15 - 12  |11 - 0
+      values:   |     count      |       base      |  flags   | index
+      - index encodes the unique redistributor region index
+      - flags: reserved for future use, currently 0
+      - base field encodes bits [51:16] of the guest physical base address
+        of the first redistributor in the region.
+      - count encodes the number of redistributors in the region. Must be
+        greater than 0.
+      There are two 64K pages for each redistributor in the region and
+      redistributors are laid out contiguously within the region. Regions
+      are filled with redistributors in the index order. The sum of all
+      region count fields must be greater than or equal to the number of
+      VCPUs. Redistributor regions must be registered in the incremental
+      index order, starting from index 0.
+      The characteristics of a specific redistributor region can be read
+      by presetting the index field in the attr data.
+      Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
+
+  It is invalid to mix calls with KVM_VGIC_V3_ADDR_TYPE_REDIST and
+  KVM_VGIC_V3_ADDR_TYPE_REDIST_REGION attributes.
+
   Errors:
     -E2BIG:  Address outside of addressable IPA range
-    -EINVAL: Incorrectly aligned address
+    -EINVAL: Incorrectly aligned address, bad redistributor region
+             count/index, mixed redistributor region attribute usage
     -EEXIST: Address already configured
+    -ENOENT: Attempt to read the characteristics of a non existing
+             redistributor region
     -ENXIO:  The group or attribute is unknown/unsupported for this device
              or hardware support is missing.
     -EFAULT: Invalid user pointer for attr->addr.
 
 
-
   KVM_DEV_ARM_VGIC_GRP_DIST_REGS
   KVM_DEV_ARM_VGIC_GRP_REDIST_REGS
   Attributes: