backends/iommufd: Introduce the iommufd object

[mirror_qemu.git] / qemu-options.hx

diff --git a/qemu-options.hx b/qemu-options.hx
index 3eee3c33eb7f3b2a712aee69e6937127882bbdd8..5fe8ea57d2d2f9390a976ef2fefe86463e888bb1 100644 (file)
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2428,8 +2428,10 @@ SRST
     OBP.
 ERST
 
+#ifdef CONFIG_VNC
 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
     "-vnc <display>  shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL)
+#endif
 SRST
 ``-vnc display[,option[,option[,...]]]``
     Normally, if QEMU is compiled with graphical window support, it
@@ -5222,6 +5224,18 @@ SRST
 
         The ``share`` boolean option is on by default with memfd.
 
+    ``-object iommufd,id=id[,fd=fd]``
+        Creates an iommufd backend which allows control of DMA mapping
+        through the ``/dev/iommu`` device.
+
+        The ``id`` parameter is a unique ID which frontends (such as
+        vfio-pci of vdpa) will use to connect with the iommufd backend.
+
+        The ``fd`` parameter is an optional pre-opened file descriptor
+        resulting from ``/dev/iommu`` opening. Usually the iommufd is shared
+        across all subsystems, bringing the benefit of centralized
+        reference counting.
+
     ``-object rng-builtin,id=id``
         Creates a random number generator backend which obtains entropy
         from QEMU builtin functions. The ``id`` parameter is a unique ID