Since commit 4ccd5fe22feb95137d325f422016a6473541fe9f ('pc: add option
to disable PS/2 mouse/keyboard'), the vmport will not be created unless
the i8042 PS/2 controller is enabled. To avoid confusion, let's fail if
vmport was explicitly requested, but the i8042 controller is disabled.
This also changes the behavior of vmport=auto to take i8042 controller
availability into account.

Signed-off-by: Kamil Szczęk <kamil@szczek.dev>
---
 hw/i386/pc.c    | 11 ++++++++---
 qemu-options.hx |  4 ++--
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 72229a24ff..7779c88a91 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1075,7 +1075,7 @@ static const MemoryRegionOps ioportF0_io_ops = {
 };
 
 static void pc_superio_init(ISABus *isa_bus, bool create_fdctrl,
-                            bool create_i8042, bool no_vmport)
+                            bool create_i8042, bool no_vmport, Error **errp)
 {
     int i;
     DriveInfo *fd[MAX_FD];
@@ -1100,6 +1100,10 @@ static void pc_superio_init(ISABus *isa_bus, bool create_fdctrl,
     }
 
     if (!create_i8042) {
+        if (!no_vmport) {
+            error_setg(errp,
+                       "vmport requires the i8042 controller to be enabled");
+        }
         return;
     }
 
@@ -1219,12 +1223,13 @@ void pc_basic_device_init(struct PCMachineState *pcms,
 
     assert(pcms->vmport >= 0 && pcms->vmport < ON_OFF_AUTO__MAX);
     if (pcms->vmport == ON_OFF_AUTO_AUTO) {
-        pcms->vmport = xen_enabled() ? ON_OFF_AUTO_OFF : ON_OFF_AUTO_ON;
+        pcms->vmport = (xen_enabled() || !pcms->i8042_enabled)
+            ? ON_OFF_AUTO_OFF : ON_OFF_AUTO_ON;
     }
 
     /* Super I/O */
     pc_superio_init(isa_bus, create_fdctrl, pcms->i8042_enabled,
-                    pcms->vmport != ON_OFF_AUTO_ON);
+                    pcms->vmport != ON_OFF_AUTO_ON, &error_fatal);
 }
 
 void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus)
diff --git a/qemu-options.hx b/qemu-options.hx
index cee0da2014..9197bb25d3 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -68,8 +68,8 @@ SRST
 
     ``vmport=on|off|auto``
         Enables emulation of VMWare IO port, for vmmouse etc. auto says
-        to select the value based on accel. For accel=xen the default is
-        off otherwise the default is on.
+        to select the value based on accel and i8042. For accel=xen or
+        i8042=off the default is off otherwise the default is on.
 
     ``dump-guest-core=on|off``
         Include guest memory in a core dump. The default is on.
-- 
2.45.0