docs: kvm: convert arm/hyp-abi.txt to ReST

- Add proper markups for titles;
- Adjust whitespaces and blank lines to match ReST
  needs;
- Mark literal blocks as such.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Documentation/virt/kvm/arm/hyp-abi.rst

@@ -1,4 +1,8 @@
-* Internal ABI between the kernel and HYP
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+Internal ABI between the kernel and HYP
+=======================================
 
 This file documents the interaction between the Linux kernel and the
 hypervisor layer when running Linux as a hypervisor (for example
@@ -19,25 +23,31 @@ and only act on individual CPUs.
 Unless specified otherwise, any built-in hypervisor must implement
 these functions (see arch/arm{,64}/include/asm/virt.h):
 
-* r0/x0 = HVC_SET_VECTORS
-  r1/x1 = vectors
+* ::
+
+    r0/x0 = HVC_SET_VECTORS
+    r1/x1 = vectors
 
   Set HVBAR/VBAR_EL2 to 'vectors' to enable a hypervisor. 'vectors'
   must be a physical address, and respect the alignment requirements
   of the architecture. Only implemented by the initial stubs, not by
   Linux hypervisors.
 
-* r0/x0 = HVC_RESET_VECTORS
+* ::
+
+    r0/x0 = HVC_RESET_VECTORS
 
   Turn HYP/EL2 MMU off, and reset HVBAR/VBAR_EL2 to the initials
   stubs' exception vector value. This effectively disables an existing
   hypervisor.
 
-* r0/x0 = HVC_SOFT_RESTART
-  r1/x1 = restart address
-  x2 = x0's value when entering the next payload (arm64)
-  x3 = x1's value when entering the next payload (arm64)
-  x4 = x2's value when entering the next payload (arm64)
+* ::
+
+    r0/x0 = HVC_SOFT_RESTART
+    r1/x1 = restart address
+    x2 = x0's value when entering the next payload (arm64)
+    x3 = x1's value when entering the next payload (arm64)
+    x4 = x2's value when entering the next payload (arm64)
 
   Mask all exceptions, disable the MMU, move the arguments into place
   (arm64 only), and jump to the restart address while at HYP/EL2. This

Documentation/virt/kvm/arm/index.rst

@@ -7,4 +7,5 @@ ARM
 .. toctree::
    :maxdepth: 2
 
+   hyp-abi
    pvtime