7:43 a.m.
There has been some progress lately in enabling virtio-pci on
aarch64 guests; however, guest OS support is still spotty at best,
so most guests are going to be using virtio-mmio instead.
Currently, mach-virt guests are closely modeled after q35 guests,
and that includes always adding a dmi-to-pci-bridge that's just
impossible to get rid of. While that's acceptable (if suboptimal)
for q35, where you will always need some kind of PCI device anyway,
mach-virt guests should be allowed to avoid it.
---
src/qemu/qemu_domain.c | 8 ++++++--
src/qemu/qemu_domain_address.c | 8 +++++++-
.../qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args | 1 -
.../qemuxml2argv-aarch64-virtio-pci-default.args | 1 -
.../qemuxml2argv-aarch64-virtio-pci-manual-addresses.args | 5 +++--
.../qemuxml2argv-aarch64-virtio-pci-manual-addresses.xml | 14 ++++++++++++--
.../qemuxml2xmlout-aarch64-virtio-pci-default.xml | 4 ----
.../qemuxml2xmlout-aarch64-virtio-pci-manual-addresses.xml | 13 +++++++++----
8 files changed, 37 insertions(+), 17 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 1eb5644..595ad64 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1951,11 +1951,15 @@ qemuDomainDefAddDefaultDevices(virDomainDefPtr def,
VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT)) {
goto cleanup;
}
- /* add a dmi-to-pci-bridge and a pci-bridge if there are no pci controllers
+ /* Add a dmi-to-pci-bridge bridge if there are no PCI controllers
* other than the pcie-root. This is so that there will be hot-pluggable
- * PCI slots available
+ * PCI slots available.
+ *
+ * We skip this step for aarch64 mach-virt guests, where we want to
+ * be able to have a pure virtio-mmio topology
*/
if (virDomainControllerFind(def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 1) < 0
&&
+ !qemuDomainMachineIsVirt(def) &&
!virDomainDefAddController(def, VIR_DOMAIN_CONTROLLER_TYPE_PCI, 1,
VIR_DOMAIN_CONTROLLER_MODEL_DMI_TO_PCI_BRIDGE))
goto cleanup;
diff --git a/src/qemu/qemu_domain_address.c b/src/qemu/qemu_domain_address.c
index ca3adc0..883264a 100644
--- a/src/qemu/qemu_domain_address.c
+++ b/src/qemu/qemu_domain_address.c
@@ -1483,9 +1483,15 @@ qemuDomainAssignPCIAddresses(virDomainDefPtr def,
}
/* Reserve 1 extra slot for a (potential) bridge only if buses
- * are not fully reserved yet
+ * are not fully reserved yet.
+ *
+ * We don't reserve the extra slot for aarch64 mach-virt guests
+ * either because we want to be able to have pure virtio-mmio
+ * guests, and reserving this slot would force us to add at least
+ * a dmi-to-pci-bridge to an otherwise PCI-free topology
*/
if (!buses_reserved &&
+ !qemuDomainMachineIsVirt(def) &&
virDomainPCIAddressReserveNextSlot(addrs, &info, flags) < 0)
goto cleanup;
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args
b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args
index 2a5702f..3e6bee9 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virt-2.6-virtio-pci-default.args
@@ -21,7 +21,6 @@ QEMU_AUDIO_DRV=none \
-initrd /aarch64.initrd \
-append 'earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait' \
-dtb /aarch64.dtb \
--device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1 \
-device virtio-serial-device,id=virtio-serial0 \
-usb \
-drive file=/aarch64.raw,format=raw,if=none,id=drive-virtio-disk0 \
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
index a2df858..566bee2 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
@@ -21,7 +21,6 @@ QEMU_AUDIO_DRV=none \
-initrd /aarch64.initrd \
-append 'earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait' \
-dtb /aarch64.dtb \
--device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1 \
-device virtio-serial-device,id=virtio-serial0 \
-usb \
-drive file=/aarch64.raw,format=raw,if=none,id=drive-virtio-disk0 \
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.args
b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.args
index 0234404..4e5dbdb 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.args
@@ -23,12 +23,13 @@ QEMU_AUDIO_DRV=none \
-dtb /aarch64.dtb \
-device i82801b11-bridge,id=pci.1,bus=pcie.0,addr=0x1 \
-device pci-bridge,chassis_nr=2,id=pci.2,bus=pci.1,addr=0x0 \
--device virtio-scsi-pci,id=scsi0,bus=pcie.0,addr=0x3 \
+-device pci-bridge,chassis_nr=3,id=pci.3,bus=pci.1,addr=0x1 \
+-device virtio-scsi-pci,id=scsi0,bus=pci.3,addr=0x1 \
-usb \
-drive file=/aarch64.raw,format=raw,if=none,id=drive-scsi0-0-0-0 \
-device scsi-disk,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,\
id=scsi0-0-0-0 \
--device virtio-net-pci,vlan=0,id=net0,mac=52:54:00:09:a4:37,bus=pcie.0,addr=0x2 \
+-device virtio-net-pci,vlan=0,id=net0,mac=52:54:00:09:a4:37,bus=pci.3,addr=0x2 \
-net user,vlan=0,name=hostnet0 \
-device virtio-net-pci,vlan=1,id=net1,mac=52:54:00:09:a4:38,bus=pci.2,addr=0x1 \
-net user,vlan=1,name=hostnet1
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.xml
b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.xml
index bf0f249..5e1b494 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.xml
+++ b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-manual-addresses.xml
@@ -31,13 +31,23 @@
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
+ <controller type='pci' index='0' model='pcie-root'/>
+ <controller type='pci' index='1'
model='dmi-to-pci-bridge'>
+ <model name='i82801b11-bridge'/>
+ <address type='pci' domain='0x0000' bus='0x00'
slot='0x01' function='0x0'/>
+ </controller>
+ <controller type='pci' index='2' model='pci-bridge'>
+ <model name='pci-bridge'/>
+ <target chassisNr='2'/>
+ <address type='pci' domain='0x0000' bus='0x01'
slot='0x00' function='0x0'/>
+ </controller>
<controller type='scsi' index='0' model='virtio-scsi'>
- <address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
+ <address type='pci' domain='0x0000' bus='0x03'
slot='0x01' function='0x0'/>
</controller>
<interface type='user'>
<mac address='52:54:00:09:a4:37'/>
<model type='virtio'/>
- <address type='pci' domain='0x0000' bus='0x00'
slot='0x02' function='0x0'/>
+ <address type='pci' domain='0x0000' bus='0x03'
slot='0x02' function='0x0'/>
</interface>
<interface type='user'>
<mac address='52:54:00:09:a4:38'/>
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
index a212601..7c3fc19 100644
--- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
@@ -33,10 +33,6 @@
<address type='virtio-mmio'/>
</disk>
<controller type='pci' index='0' model='pcie-root'/>
- <controller type='pci' index='1'
model='dmi-to-pci-bridge'>
- <model name='i82801b11-bridge'/>
- <address type='pci' domain='0x0000' bus='0x00'
slot='0x01' function='0x0'/>
- </controller>
<controller type='virtio-serial' index='0'>
<address type='virtio-mmio'/>
</controller>
diff --git
a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-manual-addresses.xml
b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-manual-addresses.xml
index 4fdedac..1b50f75 100644
--- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-manual-addresses.xml
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-manual-addresses.xml
@@ -32,9 +32,6 @@
<target dev='sda' bus='scsi'/>
<address type='drive' controller='0' bus='0'
target='0' unit='0'/>
</disk>
- <controller type='scsi' index='0' model='virtio-scsi'>
- <address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
- </controller>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1'
model='dmi-to-pci-bridge'>
<model name='i82801b11-bridge'/>
@@ -45,10 +42,18 @@
<target chassisNr='2'/>
<address type='pci' domain='0x0000' bus='0x01'
slot='0x00' function='0x0'/>
</controller>
+ <controller type='scsi' index='0' model='virtio-scsi'>
+ <address type='pci' domain='0x0000' bus='0x03'
slot='0x01' function='0x0'/>
+ </controller>
+ <controller type='pci' index='3' model='pci-bridge'>
+ <model name='pci-bridge'/>
+ <target chassisNr='3'/>
+ <address type='pci' domain='0x0000' bus='0x01'
slot='0x01' function='0x0'/>
+ </controller>
<interface type='user'>
<mac address='52:54:00:09:a4:37'/>
<model type='virtio'/>
- <address type='pci' domain='0x0000' bus='0x00'
slot='0x02' function='0x0'/>
+ <address type='pci' domain='0x0000' bus='0x03'
slot='0x02' function='0x0'/>
</interface>
<interface type='user'>
<mac address='52:54:00:09:a4:38'/>
--
2.5.5