On Fri, Oct 21, 2016 at 07:24:28PM +0200, Andrea Bolognani wrote:
virtio-pci is the way forward for aarch64 guests: it's faster and less alien to people coming from other architectures. Now that guest support is finally getting there, we'd like to start using it by default instead of virtio-mmio. Users and applications can already opt-in by explicitly using <address type='pci'/> inside the relevant elements, but that's kinda cumbersome and requires all users and management applications to adapt, which we'd really like to avoid. What we can do instead is use virtio-mmio only if the guest already has at least one virtio-mmio device, and use virtio-pci in all other situations. That means existing virtio-mmio guests will keep using the old addressing scheme, and new guests will automatically be created using virtio-pci instead. Users can still override the default in either direction. --- Sending this as an RFC for the time being because it clearly needs some more polish, but I wanted to get the idea out there sooner rather than later.
Makes sense for the non-user of this (or rather not-yet-user maybe). So I mention only few details inline.
It needs to be applied on top of Laine's PCI series[1]. [1] https://www.redhat.com/archives/libvir-list/2016-October/msg00699.html src/qemu/qemu_domain_address.c | 128 ++++++++++++++++++++- ...l2argv-aarch64-virt-2.6-virtio-pci-default.args | 14 ++- .../qemuxml2argv-aarch64-virtio-pci-default.args | 14 ++- .../qemuxml2xmlout-aarch64-virtio-pci-default.xml | 24 +++- 4 files changed, 162 insertions(+), 18 deletions(-) diff --git a/src/qemu/qemu_domain_address.c b/src/qemu/qemu_domain_address.c index f27d1e3..7f07764 100644 --- a/src/qemu/qemu_domain_address.c +++ b/src/qemu/qemu_domain_address.c @@ -265,6 +265,118 @@ qemuDomainAssignSpaprVIOAddresses(virDomainDefPtr def, } +static bool +qemuDomainAnyDeviceHasAddressOfType(virDomainDefPtr def, + virDomainDeviceAddressType type) +{ + size_t i; +
It's super-easy to miss something here, moreover it's easy to forget adding stuff here in the future. You should either use virDomainDeviceInfoIterate() or at least (not a fan of that) copy the check from virDomainDeviceInfoIterateInternal() here, so that people are forced to add new device types here. [...]
static void
qemuDomainPrimeVirtioDeviceAddresses(virDomainDefPtr def,
virDomainDeviceAddressType type)
@@ -390,6 +502,8 @@ static void
qemuDomainAssignARMVirtioMMIOAddresses(virDomainDefPtr def,
virQEMUCapsPtr qemuCaps)
{
+ bool usesMMIO;
+
if (def->os.arch != VIR_ARCH_ARMV7L &&
def->os.arch != VIR_ARCH_AARCH64)
return;
@@ -398,9 +512,17 @@ qemuDomainAssignARMVirtioMMIOAddresses(virDomainDefPtr def,
qemuDomainMachineIsVirt(def)))
return;
- if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VIRTIO_MMIO)) {
- qemuDomainPrimeVirtioDeviceAddresses(
- def, VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO);
+ /* We use virtio-mmio by default on mach-virt guests only if they already
+ * have at least one virtio-mmio device: in all other cases, we prefer
+ * virtio-pci */
+ usesMMIO = qemuDomainAnyDeviceHasAddressOfType(def,
+ VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO);
+ if (qemuDomainMachineHasPCIeRoot(def) && !usesMMIO) {
I'm guessing you are checking for the pcie-root so that we're not adding it for users that don't want any. That way for us to actually use virtio-pci by default you need to add that as well, which you haven't mentioned in the commit message. Not sure which one of those things was intentional.
+ qemuDomainPrimeVirtioDeviceAddresses(def,
+ VIR_DOMAIN_DEVICE_ADDRESS_TYPE_PCI);
+ } else if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VIRTIO_MMIO)) {
+ qemuDomainPrimeVirtioDeviceAddresses(def,
+ VIR_DOMAIN_DEVICE_ADDRESS_TYPE_VIRTIO_MMIO);
}
}
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 75db1a4..df03c6e 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
@@ -21,14 +21,18 @@ QEMU_AUDIO_DRV=none \
-initrd /aarch64.initrd \
-append 'earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait' \
-dtb /aarch64.dtb \
--device virtio-serial-device,id=virtio-serial0 \
+-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 ioh3420,port=0x10,chassis=3,id=pci.3,bus=pcie.0,addr=0x2 \
+-device virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x2 \
-drive file=/aarch64.raw,format=raw,if=none,id=drive-virtio-disk0 \
--device virtio-blk-device,drive=drive-virtio-disk0,id=virtio-disk0 \
--device virtio-net-device,vlan=0,id=net0,mac=52:54:00:09:a4:37 \
+-device virtio-blk-pci,bus=pci.2,addr=0x3,drive=drive-virtio-disk0,\
+id=virtio-disk0 \
+-device virtio-net-pci,vlan=0,id=net0,mac=52:54:00:09:a4:37,bus=pci.2,addr=0x1 \
-net user,vlan=0,name=hostnet0 \
-serial pty \
-chardev pty,id=charconsole1 \
-device virtconsole,chardev=charconsole1,id=console1 \
--device virtio-balloon-device,id=balloon0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x4 \
-object rng-random,id=objrng0,filename=/dev/random \
--device virtio-rng-device,rng=objrng0,id=rng0
+-device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.2,addr=0x5
diff --git a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
index b5b010c..f205d9a 100644
--- a/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
+++ b/tests/qemuxml2argvdata/qemuxml2argv-aarch64-virtio-pci-default.args
@@ -21,14 +21,18 @@ QEMU_AUDIO_DRV=none \
-initrd /aarch64.initrd \
-append 'earlyprintk console=ttyAMA0,115200n8 rw root=/dev/vda rootwait' \
-dtb /aarch64.dtb \
--device virtio-serial-device,id=virtio-serial0 \
+-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 ioh3420,port=0x10,chassis=3,id=pci.3,bus=pcie.0,addr=0x2 \
+-device virtio-serial-pci,id=virtio-serial0,bus=pci.2,addr=0x2 \
-drive file=/aarch64.raw,format=raw,if=none,id=drive-virtio-disk0 \
--device virtio-blk-device,drive=drive-virtio-disk0,id=virtio-disk0 \
--device virtio-net-device,vlan=0,id=net0,mac=52:54:00:09:a4:37 \
+-device virtio-blk-pci,bus=pci.2,addr=0x3,drive=drive-virtio-disk0,\
+id=virtio-disk0 \
+-device virtio-net-pci,vlan=0,id=net0,mac=52:54:00:09:a4:37,bus=pci.2,addr=0x1 \
-net user,vlan=0,name=hostnet0 \
-serial pty \
-chardev pty,id=charconsole1 \
-device virtconsole,chardev=charconsole1,id=console1 \
--device virtio-balloon-device,id=balloon0 \
+-device virtio-balloon-pci,id=balloon0,bus=pci.2,addr=0x4 \
-object rng-random,id=objrng0,filename=/dev/random \
--device virtio-rng-device,rng=objrng0,id=rng0
+-device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.2,addr=0x5
diff --git a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
index 7c3fc19..90659a1 100644
--- a/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
+++ b/tests/qemuxml2xmloutdata/qemuxml2xmlout-aarch64-virtio-pci-default.xml
@@ -30,16 +30,30 @@
<disk type='file' device='disk'>
<source file='/aarch64.raw'/>
<target dev='vda' bus='virtio'/>
- <address type='virtio-mmio'/>
+ <address type='pci' domain='0x0000' bus='0x02' slot='0x03' function='0x0'/>
</disk>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='virtio-serial' index='0'>
- <address type='virtio-mmio'/>
+ <address type='pci' domain='0x0000' bus='0x02' slot='0x02' function='0x0'/>
+ </controller>
+ <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='pci' index='3' model='pcie-root-port'>
+ <model name='ioh3420'/>
+ <target chassis='3' port='0x10'/>
+ <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
</controller>
<interface type='user'>
<mac address='52:54:00:09:a4:37'/>
<model type='virtio'/>
- <address type='virtio-mmio'/>
+ <address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/>
</interface>
<serial type='pty'>
<target port='0'/>
@@ -51,11 +65,11 @@
<target type='virtio' port='1'/>
</console>
<memballoon model='virtio'>
- <address type='virtio-mmio'/>
+ <address type='pci' domain='0x0000' bus='0x02' slot='0x04' function='0x0'/>
</memballoon>
<rng model='virtio'>
<backend model='random'>/dev/random</backend>
- <address type='virtio-mmio'/>
+ <address type='pci' domain='0x0000' bus='0x02' slot='0x05' function='0x0'/>
</rng>
</devices>
</domain>
--
2.7.4
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