arm/arm64: KVM: force alignment of VGIC dist/CPU/redist addresses

Although the GIC architecture requires us to map the MMIO regions
only at page aligned addresses, we currently do not enforce this from
the kernel side.
Restrict any vGICv2 regions to be 4K aligned and any GICv3 regions
to be 64K aligned. Document this requirement.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt
index 5d4fd4b944cd..3fb905429e8a 100644
--- a/Documentation/virtual/kvm/devices/arm-vgic.txt
+++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
@@ -20,20 +20,24 @@ Groups:
     KVM_VGIC_V2_ADDR_TYPE_DIST (rw, 64-bit)
       Base address in the guest physical address space of the GIC distributor
       register mappings. Only valid for KVM_DEV_TYPE_ARM_VGIC_V2.
+      This address needs to be 4K aligned and the region covers 4 KByte.
 
     KVM_VGIC_V2_ADDR_TYPE_CPU (rw, 64-bit)
       Base address in the guest physical address space of the GIC virtual cpu
       interface register mappings. Only valid for KVM_DEV_TYPE_ARM_VGIC_V2.
+      This address needs to be 4K aligned and the region covers 4 KByte.
 
     KVM_VGIC_V3_ADDR_TYPE_DIST (rw, 64-bit)
       Base address in the guest physical address space of the GICv3 distributor
       register mappings. Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
+      This address needs to be 64K aligned and the region covers 64 KByte.
 
     KVM_VGIC_V3_ADDR_TYPE_REDIST (rw, 64-bit)
       Base address in the guest physical address space of the GICv3
       redistributor register mappings. There are two 64K pages for each
       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_DEV_ARM_VGIC_GRP_DIST_REGS