[libvirt] [PATCH 2/4] qemu: Use generic PCIe Root Ports by default for aarch64/virt

[Andrea Bolognani]

ioh3420 is emulated Intel hardware, so it always looked
quite out of place in aarch64/virt guests.

If pcie-root-port is available in QEMU, use that device
instead.
---
It was mentioned somewhere, at some point, that we might
want to switch to generic PCIe Root Ports for x86/q35
guests as well.

It sounds like a good idea to me, and in fact QEMU's sample
configuration files for x86/q35 (docs/q35-virtio-*.cfg)
already push in that direction; however, I didn't want to
risk holding up the aarch64/virt change, which we
unquestionably want, because of that, so I will propose it
as a separate patch further down the line.

 src/qemu/qemu_domain_address.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_domain_address.c b/src/qemu/qemu_domain_address.c
index 64aa4ef..bd2f718 100644
--- a/src/qemu/qemu_domain_address.c
+++ b/src/qemu/qemu_domain_address.c
@@ -1846,13 +1846,16 @@ qemuDomainSupportsPCI(virDomainDefPtr def,
 
 
 static void
-qemuDomainPCIControllerSetDefaultModelName(virDomainControllerDefPtr cont)
+qemuDomainPCIControllerSetDefaultModelName(virDomainControllerDefPtr cont,
+                                           virDomainDefPtr def,
+                                           virQEMUCapsPtr qemuCaps)
 {
     int *modelName = &cont->opts.pciopts.modelName;
 
     /* make sure it's not already set */
     if (*modelName != VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_NONE)
         return;
+
     switch ((virDomainControllerModelPCI)cont->model) {
     case VIR_DOMAIN_CONTROLLER_MODEL_PCI_BRIDGE:
         *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PCI_BRIDGE;
@@ -1861,7 +1864,13 @@ qemuDomainPCIControllerSetDefaultModelName(virDomainControllerDefPtr cont)
         *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_I82801B11_BRIDGE;
         break;
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT_PORT:
-        *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_IOH3420;
+        /* Use generic PCIe Root Ports for mach-virt guests, if available */
+        if (qemuDomainMachineIsVirt(def) &&
+            virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_PCIE_ROOT_PORT)) {
+            *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_PCIE_ROOT_PORT;
+        } else {
+            *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_IOH3420;
+        }
         break;
     case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_SWITCH_UPSTREAM_PORT:
         *modelName = VIR_DOMAIN_CONTROLLER_PCI_MODEL_NAME_X3130_UPSTREAM;
@@ -2143,7 +2152,7 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
              * device in qemu) for any controller that doesn't yet
              * have it set.
              */
-            qemuDomainPCIControllerSetDefaultModelName(cont);
+            qemuDomainPCIControllerSetDefaultModelName(cont, def, qemuCaps);
 
             /* set defaults for any other auto-generated config
              * options for this controller that haven't been
-- 
2.7.4