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, 13 insertions, 3 deletions

diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 184c6dbd5165..0cc6ab6005a0 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -1683,6 +1683,7 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
         struct vgic_dist *vgic = &kvm->arch.vgic;
         int type_needed;
         phys_addr_t *addr_ptr, block_size;
+        phys_addr_t alignment;
 
         mutex_lock(&kvm->lock);
         switch (type) {
@@ -1690,22 +1691,26 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
                 type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
                 addr_ptr = &vgic->vgic_dist_base;
                 block_size = KVM_VGIC_V2_DIST_SIZE;
+                alignment = SZ_4K;
                 break;
         case KVM_VGIC_V2_ADDR_TYPE_CPU:
                 type_needed = KVM_DEV_TYPE_ARM_VGIC_V2;
                 addr_ptr = &vgic->vgic_cpu_base;
                 block_size = KVM_VGIC_V2_CPU_SIZE;
+                alignment = SZ_4K;
                 break;
 #ifdef CONFIG_ARM_GIC_V3
         case KVM_VGIC_V3_ADDR_TYPE_DIST:
                 type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
                 addr_ptr = &vgic->vgic_dist_base;
                 block_size = KVM_VGIC_V3_DIST_SIZE;
+                alignment = SZ_64K;
                 break;
         case KVM_VGIC_V3_ADDR_TYPE_REDIST:
                 type_needed = KVM_DEV_TYPE_ARM_VGIC_V3;
                 addr_ptr = &vgic->vgic_redist_base;
                 block_size = KVM_VGIC_V3_REDIST_SIZE;
+                alignment = SZ_64K;
                 break;
 #endif
         default:
@@ -1718,10 +1723,15 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write)
                 goto out;
         }
 
-        if (write)
-                r = vgic_ioaddr_assign(kvm, addr_ptr, *addr, block_size);
-        else
+        if (write) {
+                if (!IS_ALIGNED(*addr, alignment))
+                        r = -EINVAL;
+                else
+                        r = vgic_ioaddr_assign(kvm, addr_ptr, *addr,
+                                               block_size);
+        } else {
                 *addr = *addr_ptr;
+        }
 
 out:
         mutex_unlock(&kvm->lock);