KVM: arm64: Include MMIO guard and memory relinquish in top-level hypercalls doc
This introduces a description of the EMM_RELINQUISH hypercall. MMIO
guard hypercalls are already described in another file, which we now
link to.
Signed-off-by: Keir Fraser <keirf@google.com>
diff --git a/Documentation/virt/kvm/arm/hypercalls.rst b/Documentation/virt/kvm/arm/hypercalls.rst
index 5ef81df..75a28b80 100644
--- a/Documentation/virt/kvm/arm/hypercalls.rst
+++ b/Documentation/virt/kvm/arm/hypercalls.rst
@@ -116,3 +116,37 @@
| | | +---------------------------------------------+
| | | | ``INVALID_PARAMETER (-3)`` |
+---------------------+----------+----+---------------------------------------------+
+
+``ARM_SMCCC_KVM_FUNC_MEM_RELINQUISH``
+--------------------------------------
+
+Cooperatively relinquish ownership of a memory region. The size of the
+region is equal to the memory protection granule advertised by
+``ARM_SMCCC_KVM_FUNC_HYP_MEMINFO``. If this hypercall is advertised
+then it is mandatory to call it before freeing memory via, for
+example, virtio balloon. If the caller is a protected VM, it is
+guaranteed that the memory region will be completely cleared before
+becoming visible to another VM.
+
++---------------------+-------------------------------------------------------------+
+| Presence: | Optional. |
++---------------------+-------------------------------------------------------------+
+| Calling convention: | HVC64 |
++---------------------+----------+--------------------------------------------------+
+| Function ID: | (uint32) | 0xC6000009 |
++---------------------+----------+----+---------------------------------------------+
+| Arguments: | (uint64) | R1 | Base IPA of memory region to relinquish |
+| +----------+----+---------------------------------------------+
+| | (uint64) | R2 | Reserved / Must be zero |
+| +----------+----+---------------------------------------------+
+| | (uint64) | R3 | Reserved / Must be zero |
++---------------------+----------+----+---------------------------------------------+
+| Return Values: | (int64) | R0 | ``SUCCESS (0)`` |
+| | | +---------------------------------------------+
+| | | | ``INVALID_PARAMETER (-3)`` |
++---------------------+----------+----+---------------------------------------------+
+
+``ARM_SMCCC_KVM_FUNC_MMIO_GUARD_*``
+-----------------------------------
+
+See mmio-guard.rst
