9:50 p.m.
In libvirt, I found pcie-expander-bus controller doesn't support
pcie-to-pci-bridge and pcie-switch-upstream-port.
Version: libvirt-4.9
# cat /tmp/c.xml
...
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1'
model='pcie-expander-bus'>
<model name='pxb-pcie'/>
<target busNr='3'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
</controller>
<controller type='pci' index='2'
model='pcie-to-pci-bridge'>
<address type='pci' domain='0x0000' bus='0x01'
slot='0x00'
function='0x0'/>
</controller>
...
# virsh -k0 -K0 define
/tmp/c.xml
error: Failed to define domain from /tmp/c.xml
error: XML error: The device at PCI address 0000:01:00.0 cannot be plugged
into the PCI controller with index='1'. It requires a controller that
accepts a pcie-to-pci-bridge.
# cat /tmp/b.xml
...
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1'
model='pcie-expander-bus'>
<model name='pxb-pcie'/>
<target busNr='3'/>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03'
function='0x0'/>
</controller>
<controller type='pci' index='2'
model='pcie-switch-upstream-port'>
<model name='x3130-upstream'/>
<address type='pci' domain='0x0000' bus='0x01'
slot='0x00'
function='0x0'/>
</controller>
...
# virsh -k0 -K0 define /tmp/b.xml
error: Failed to define domain from /tmp/b.xml
error: XML error: The device at PCI address 0000:01:00.0 cannot be plugged
into the PCI controller with index='1'. It requires a controller that
accepts a pci-switch-upstream-port.
In function virDomainPCIAddressBusSetModel, I find pcie-expander-bus only
supports pcie-root-port and dmi-to-pci-bridge
353 case
VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
354 ┆ /* 32 slots, no hotplug, only accepts pcie-root-port
or
355 ┆ ┆*
dmi-to-pci-bridge
356 ┆
┆*/
357 ┆ bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT
|
358 ┆ ┆ ┆ ┆ ┆
VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
359 ┆ bus->minSlot =
0;
360 ┆ bus->maxSlot =
VIR_PCI_ADDRESS_SLOT_LAST;
361 ┆ break;
But it works in qemu:
# /usr/libexec/qemu-kvm -machine q35 -m 1024 -device
pxb-pcie,bus_nr=250,id=pci.1,bus=pcie.0,addr=0x4 -device
pcie-pci-bridge,id=pci.250,bus=pci.1,addr=0x0 -device
pcie-pci-bridge,id=pci.251,bus=pci.1,addr=0x1 -spice
port=5902,addr=0.0.0.0,disable-ticketing /var/lib/libvirt/images/q35.qcow2
So why pcie-expander-bus doesn't these two controllers? For any concerns in
libvirt?
Thank you~
--
Best regards,
-----------------------------------
Han Han
Quality Engineer
Redhat.
Email: hhan(a)redhat.com
Phone: +861065339333
7:56 a.m.
On Wed, 2018-10-17 at 10:50 +0800, Han Han wrote:
In libvirt, I found pcie-expander-bus controller doesn't support
pcie-to-pci-bridge and pcie-switch-upstream-port.
[...]
# virsh -k0 -K0 define /tmp/c.xml
Aside: the -k and -K virsh options are documented as
-k | --keepalive-interval=NUM
keepalive interval in seconds, 0 for disable
-K | --keepalive-count=NUM
number of possible missed keepalive messages
So -k0 disables keepalive entirely, making -K0 unnecessary :)
error: Failed to define domain from /tmp/c.xml
error: XML error: The device at PCI address 0000:01:00.0 cannot be plugged into the PCI
controller with index='1'. It requires a controller that accepts a
pcie-to-pci-bridge.
[...]
In function virDomainPCIAddressBusSetModel, I find pcie-expander-bus
only supports pcie-root-port and dmi-to-pci-bridge
353 case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
354 ┆ /* 32 slots, no hotplug, only accepts pcie-root-port or
355 ┆ ┆* dmi-to-pci-bridge
356 ┆ ┆*/
357 ┆ bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
358 ┆ ┆ ┆ ┆ ┆ VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
359 ┆ bus->minSlot = 0;
360 ┆ bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
361 ┆ break;
The above is consistent with pcie-root itself, which also doesn't
support plugging a pcie-to-pci-bridge directly into it but requires
a pcie-root <- pcie-root-port <- pcie-to-pci-bridge topology.
Now, I don't quite recall *why* that is the case - perhaps Laine
does? - but I'm sure we had very compelling reasons O:-)
But it works in qemu:
# /usr/libexec/qemu-kvm -machine q35 -m 1024 -device
pxb-pcie,bus_nr=250,id=pci.1,bus=pcie.0,addr=0x4 -device
pcie-pci-bridge,id=pci.250,bus=pci.1,addr=0x0 -device
pcie-pci-bridge,id=pci.251,bus=pci.1,addr=0x1 -spice
port=5902,addr=0.0.0.0,disable-ticketing /var/lib/libvirt/images/q35.qcow2
It should be noted that QEMU in general allows users to make pretty
unwise device placement choices without so much of a warning, so I
would not take the above as proof the pcie-to-pci-bridge should be
allowed to plug into pcie-expander-bus (or pcie-root) directly :)
--
Andrea Bolognani / Red Hat / Virtualization
12:29 p.m.
On 10/17/2018 08:56 AM, Andrea Bolognani wrote:
On Wed, 2018-10-17 at 10:50 +0800, Han Han wrote:
> In libvirt, I found pcie-expander-bus controller doesn't support
pcie-to-pci-bridge and pcie-switch-upstream-port.
[...]
> # virsh -k0 -K0 define /tmp/c.xml
Aside: the -k and -K virsh options are documented as
-k | --keepalive-interval=NUM
keepalive interval in seconds, 0 for disable
-K | --keepalive-count=NUM
number of possible missed keepalive messages
So -k0 disables keepalive entirely, making -K0 unnecessary :)
> error: Failed to define domain from /tmp/c.xml
> error: XML error: The device at PCI address 0000:01:00.0 cannot be plugged into the
PCI controller with index='1'. It requires a controller that accepts a
pcie-to-pci-bridge.
[...]
> In function virDomainPCIAddressBusSetModel, I find pcie-expander-bus only supports
pcie-root-port and dmi-to-pci-bridge
> 353 case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
> 354 ┆ /* 32 slots, no hotplug, only accepts pcie-root-port or
> 355 ┆ ┆* dmi-to-pci-bridge
> 356 ┆ ┆*/
> 357 ┆ bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
> 358 ┆ ┆ ┆ ┆ ┆ VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
> 359 ┆ bus->minSlot = 0;
> 360 ┆ bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
> 361 ┆ break;
The above is consistent with pcie-root itself, which also doesn't
support plugging a pcie-to-pci-bridge directly into it but requires
a pcie-root <- pcie-root-port <- pcie-to-pci-bridge topology.
Now, I don't quite recall *why* that is the case - perhaps Laine
does? - but I'm sure we had very compelling reasons O:-)
Umm, because Marcel told us that was the proper behavior ? Right, Marcel?
> But it works in qemu:
> # /usr/libexec/qemu-kvm -machine q35 -m 1024 -device
pxb-pcie,bus_nr=250,id=pci.1,bus=pcie.0,addr=0x4 -device
pcie-pci-bridge,id=pci.250,bus=pci.1,addr=0x0 -device
pcie-pci-bridge,id=pci.251,bus=pci.1,addr=0x1 -spice
port=5902,addr=0.0.0.0,disable-ticketing /var/lib/libvirt/images/q35.qcow2
It should be noted that QEMU in general allows users to make pretty
unwise device placement choices without so much of a warning, so I
would not take the above as proof the pcie-to-pci-bridge should be
allowed to plug into pcie-expander-bus (or pcie-root) directly :)
8:24 a.m.
Hi Laine,
On 10/17/18 8:29 PM, Laine Stump wrote:
On 10/17/2018 08:56 AM, Andrea Bolognani wrote:
> On Wed, 2018-10-17 at 10:50 +0800, Han Han wrote:
>> In libvirt, I found pcie-expander-bus controller doesn't support
pcie-to-pci-bridge and pcie-switch-upstream-port.
> [...]
>> # virsh -k0 -K0 define /tmp/c.xml
> Aside: the -k and -K virsh options are documented as
>
> -k | --keepalive-interval=NUM
> keepalive interval in seconds, 0 for disable
> -K | --keepalive-count=NUM
> number of possible missed keepalive messages
>
> So -k0 disables keepalive entirely, making -K0 unnecessary :)
>
>> error: Failed to define domain from /tmp/c.xml
>> error: XML error: The device at PCI address 0000:01:00.0 cannot be plugged into
the PCI controller with index='1'. It requires a controller that accepts a
pcie-to-pci-bridge.
> [...]
>> In function virDomainPCIAddressBusSetModel, I find pcie-expander-bus only
supports pcie-root-port and dmi-to-pci-bridge
>> 353 case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
>> 354 ┆ /* 32 slots, no hotplug, only accepts pcie-root-port or
>> 355 ┆ ┆* dmi-to-pci-bridge
>> 356 ┆ ┆*/
>> 357 ┆ bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
>> 358 ┆ ┆ ┆ ┆ ┆ VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
>> 359 ┆ bus->minSlot = 0;
>> 360 ┆ bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
>> 361 ┆ break;
> The above is consistent with pcie-root itself, which also doesn't
> support plugging a pcie-to-pci-bridge directly into it but requires
> a pcie-root <- pcie-root-port <- pcie-to-pci-bridge topology.
>
> Now, I don't quite recall *why* that is the case - perhaps Laine
> does? - but I'm sure we had very compelling reasons O:-)
Umm, because Marcel told us that was the proper behavior ? Right, Marcel?
Yes it is.
The pcie-pxb expander does not support "embedded" devices, any devices
should be plugged into pcie ports.
Even if QEMU cmd line allows embedded devices, it is not a supported
configuration.
Zooming it into the specific case of the pcie-pci bridge, this is a PCI
Express device,
and PCI Express devices may miss-behave if plugged as Integrated Devices.
Thanks,
Marcel
>> But it works in qemu:
>> # /usr/libexec/qemu-kvm -machine q35 -m 1024 -device
pxb-pcie,bus_nr=250,id=pci.1,bus=pcie.0,addr=0x4 -device
pcie-pci-bridge,id=pci.250,bus=pci.1,addr=0x0 -device
pcie-pci-bridge,id=pci.251,bus=pci.1,addr=0x1 -spice
port=5902,addr=0.0.0.0,disable-ticketing /var/lib/libvirt/images/q35.qcow2
> It should be noted that QEMU in general allows users to make pretty
> unwise device placement choices without so much of a warning, so I
> would not take the above as proof the pcie-to-pci-bridge should be
> allowed to plug into pcie-expander-bus (or pcie-root) directly :)
>
12:27 a.m.
On Wed, Oct 17, 2018 at 8:56 PM Andrea Bolognani <abologna(a)redhat.com>
wrote:
On Wed, 2018-10-17 at 10:50 +0800, Han Han wrote:
> In libvirt, I found pcie-expander-bus controller doesn't support
pcie-to-pci-bridge and pcie-switch-upstream-port.
[...]
> # virsh -k0 -K0 define /tmp/c.xml
Aside: the -k and -K virsh options are documented as
-k | --keepalive-interval=NUM
keepalive interval in seconds, 0 for disable
-K | --keepalive-count=NUM
number of possible missed keepalive messages
So -k0 disables keepalive entirely, making -K0 unnecessary :)
Thanks for your advice.
> error: Failed to define domain from /tmp/c.xml
> error: XML error: The device at PCI address 0000:01:00.0 cannot be
plugged into the PCI controller with index='1'. It requires a controller
that accepts a pcie-to-pci-bridge.
[...]
> In function virDomainPCIAddressBusSetModel, I find pcie-expander-bus
only supports pcie-root-port and dmi-to-pci-bridge
> 353 case VIR_DOMAIN_CONTROLLER_MODEL_PCIE_EXPANDER_BUS:
> 354 ┆ /* 32 slots, no hotplug, only accepts pcie-root-port or
> 355 ┆ ┆* dmi-to-pci-bridge
> 356 ┆ ┆*/
> 357 ┆ bus->flags = (VIR_PCI_CONNECT_TYPE_PCIE_ROOT_PORT |
> 358 ┆ ┆ ┆ ┆ ┆ VIR_PCI_CONNECT_TYPE_DMI_TO_PCI_BRIDGE);
> 359 ┆ bus->minSlot = 0;
> 360 ┆ bus->maxSlot = VIR_PCI_ADDRESS_SLOT_LAST;
> 361 ┆ break;
The above is consistent with pcie-root itself, which also doesn't
support plugging a pcie-to-pci-bridge directly into it but requires
a pcie-root <- pcie-root-port <- pcie-to-pci-bridge topology.
Now, I don't quite recall *why* that is the case - perhaps Laine
does? - but I'm sure we had very compelling reasons O:-)
> But it works in qemu:
> # /usr/libexec/qemu-kvm -machine q35 -m 1024 -device
pxb-pcie,bus_nr=250,id=pci.1,bus=pcie.0,addr=0x4 -device
pcie-pci-bridge,id=pci.250,bus=pci.1,addr=0x0 -device
pcie-pci-bridge,id=pci.251,bus=pci.1,addr=0x1 -spice
port=5902,addr=0.0.0.0,disable-ticketing /var/lib/libvirt/images/q35.qcow2
It should be noted that QEMU in general allows users to make pretty
unwise device placement choices without so much of a warning, so I
would not take the above as proof the pcie-to-pci-bridge should be
allowed to plug into pcie-expander-bus (or pcie-root) directly :)
If pcie<-pcie-expander-bus<-(pcie-to-pci-bridge |
pcie-switch-upstream-port)
is an unwise device placement, we'd better to
add the reason to code comments or commit msg or documents.
--
Andrea Bolognani / Red Hat / Virtualization
--
Best regards,
-----------------------------------
Han Han
Quality Engineer
Redhat.
Email: hhan(a)redhat.com
Phone: +861065339333
2258
days inactive
2259
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4 comments
4 participants
participants (4)
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Andrea Bolognani -
Han Han -
Laine Stump -
Marcel Apfelbaum