qemu: Default to no USB and no memballoon for new architectures

The current defaults, that can be altered on a per-architecture
basis, are derived from the historical x86 behavior.

Every time support for a new architecture is added to libvirt,
care must be taken to override these default: if that doesn't
happen, guests will end up with additional hardware, which is
something that's generally undesirable.

Turn things around, and require architectures to explicitly
ask for the devices to be created by default instead. The
behavior for existing architectures is preserved.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 7292739d1f8f7d9226e20860682573e24738a0ce..d56ac929eaede01a5aa5857ce2cc1fc01d2d1e8f 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4109,13 +4109,13 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
                                virDomainDef *def,
                                virQEMUCaps *qemuCaps)
 {
-    bool addDefaultUSB = true;
+    bool addDefaultUSB = false;
     int usbModel = -1; /* "default for machinetype" */
     int pciRoot;       /* index within def->controllers */
     bool addImplicitSATA = false;
     bool addPCIRoot = false;
     bool addPCIeRoot = false;
-    bool addDefaultMemballoon = true;
+    bool addDefaultMemballoon = false;
     bool addDefaultUSBKBD = false;
     bool addDefaultUSBMouse = false;
     bool addPanicDevice = false;
@@ -4129,10 +4129,14 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
     switch (def->os.arch) {
     case VIR_ARCH_I686:
     case VIR_ARCH_X86_64:
+        addDefaultMemballoon = true;
+
         if (STREQ(def->os.machine, "isapc")) {
-            addDefaultUSB = false;
             break;
         }
+
+        addDefaultUSB = true;
+
         if (qemuDomainIsQ35(def)) {
             addPCIeRoot = true;
             addImplicitSATA = true;
@@ -4157,16 +4161,12 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
         break;
 
     case VIR_ARCH_ARMV6L:
-        addDefaultUSB = false;
-        addDefaultMemballoon = false;
         if (STREQ(def->os.machine, "versatilepb"))
             addPCIRoot = true;
         break;
 
     case VIR_ARCH_ARMV7L:
     case VIR_ARCH_AARCH64:
-        addDefaultUSB = false;
-        addDefaultMemballoon = false;
         if (qemuDomainIsARMVirt(def))
             addPCIeRoot = true;
         break;
@@ -4174,8 +4174,10 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
     case VIR_ARCH_PPC64:
     case VIR_ARCH_PPC64LE:
         addPCIRoot = true;
+        addDefaultUSB = true;
         addDefaultUSBKBD = true;
         addDefaultUSBMouse = true;
+        addDefaultMemballoon = true;
         /* For pSeries guests, the firmware provides the same
          * functionality as the pvpanic device, so automatically
          * add the definition if not already present */
@@ -4188,29 +4190,28 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
     case VIR_ARCH_PPCEMB:
     case VIR_ARCH_SH4:
     case VIR_ARCH_SH4EB:
+        addDefaultUSB = true;
+        addDefaultMemballoon = true;
         addPCIRoot = true;
         break;
 
     case VIR_ARCH_RISCV32:
     case VIR_ARCH_RISCV64:
-        addDefaultUSB = false;
+        addDefaultMemballoon = true;
         if (qemuDomainIsRISCVVirt(def))
             addPCIeRoot = true;
         break;
 
     case VIR_ARCH_S390:
     case VIR_ARCH_S390X:
-        addDefaultUSB = false;
+        addDefaultMemballoon = true;
         addPanicDevice = true;
         addPCIRoot = virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_ZPCI);
         break;
 
-    case VIR_ARCH_SPARC:
-        addDefaultUSB = false;
-        addDefaultMemballoon = false;
-        break;
-
     case VIR_ARCH_SPARC64:
+        addDefaultUSB = true;
+        addDefaultMemballoon = true;
         addPCIRoot = true;
         break;
 
@@ -4218,6 +4219,8 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
     case VIR_ARCH_MIPSEL:
     case VIR_ARCH_MIPS64:
     case VIR_ARCH_MIPS64EL:
+        addDefaultUSB = true;
+        addDefaultMemballoon = true;
         if (qemuDomainIsMipsMalta(def))
             addPCIRoot = true;
         break;
@@ -4233,6 +4236,7 @@ qemuDomainDefAddDefaultDevices(virQEMUDriver *driver,
     case VIR_ARCH_PARISC:
     case VIR_ARCH_PARISC64:
     case VIR_ARCH_PPCLE:
+    case VIR_ARCH_SPARC:
     case VIR_ARCH_UNICORE32:
     case VIR_ARCH_XTENSA:
     case VIR_ARCH_XTENSAEB: