[libvirt] [PATCH] qemu: Add USB and memory balloon by default for aarch64/virt guests
Basically all existing guest types, regardless of the architectur,
get both a USB controller and a virtio memory balloon by default.
s390 guests are an exception, for the very good reason that they
don't support USB at all; the other exception is aarch64/virt
guests, but in the latter case isn't a compelling reason for them
to deviate from the widely adopted convention, especially since:
* x86/q35 guests, which aarch64/virt guests are for the most
part identical to, add these devices by default;
* it's trivial to opt out of both default devices by setting
model='none';
* higher level applications such as Nova expect at least the
USB controller to be present.
So add it by default for newly-defined guests. Existing guests
will, of course, be left unchanged.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1538637
Signed-off-by: Andrea Bolognani <abologna(a)redhat.com>
---
src/qemu/qemu_domain.c | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 6b4bd3cca..f1c3b3d1e 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2630,7 +2630,8 @@ qemuDomainDefAddImplicitInputDevice(virDomainDef *def)
static int
qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
- virQEMUCapsPtr qemuCaps)
+ virQEMUCapsPtr qemuCaps,
+ unsigned int parseFlags)
{
bool addDefaultUSB = true;
int usbModel = -1; /* "default for machinetype" */
@@ -2680,10 +2681,33 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
case VIR_ARCH_ARMV7L:
case VIR_ARCH_AARCH64:
- addDefaultUSB = false;
- addDefaultMemballoon = false;
- if (qemuDomainIsVirt(def))
+ if (qemuDomainIsVirt(def)) {
+ /* All mach-virt guests get a PCIe Root, if supported by
+ * the QEMU binary */
addPCIeRoot = virQEMUCapsGet(qemuCaps, QEMU_CAPS_OBJECT_GPEX);
+ }
+
+ if (qemuDomainIsVirt(def) &&
+ parseFlags & VIR_DOMAIN_DEF_PARSE_ABI_UPDATE) {
+ /* In addition to PCIe Root, newly-defined mach-virt guests
+ * also get a couple more devices so that they're more similar
+ * to guests on other architectures, notably x86/q35:
+ *
+ * 1) a USB3 controller, if supported by the QEMU binary;
+ * 2) a virtio memory balloon, as per the defaults defined
+ * above.
+ */
+ if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_QEMU_XHCI))
+ usbModel = VIR_DOMAIN_CONTROLLER_MODEL_USB_QEMU_XHCI;
+ else
+ addDefaultUSB = false;
+ } else {
+ /* Other ARM guests (and existing mach-virt guests, in order
+ * to preserve guest ABI compatibility) don't get a PCIe Root,
+ * a USB controller or a memory balloon */
+ addDefaultUSB = false;
+ addDefaultMemballoon = false;
+ }
break;
case VIR_ARCH_PPC64:
@@ -3187,7 +3211,7 @@ qemuDomainDefPostParse(virDomainDefPtr def,
goto cleanup;
}
- if (qemuDomainDefAddDefaultDevices(def, qemuCaps) < 0)
+ if (qemuDomainDefAddDefaultDevices(def, qemuCaps, parseFlags) < 0)
goto cleanup;
if (qemuCanonicalizeMachine(def, qemuCaps) < 0)
--
2.14.3