Hi,
On 12/4/18 5:26 PM, Alex Williamson wrote:
> Allow users to experimentally specify speed and width values for the
> generic PCIe root port. Defaults remain at 2.5GT/s & x1 for
> compatiblity with the intent to only support changing defaults via
> machine types for now.
>
> Note for libvirt testing that pcie-root-port controllers are given
> default names like "pci.7" which don't play well with using the
> "-set device.$name.$prop=$value" options accessible to us via
> <qemu:commandline> options. The solution is to add an <alias> to the
> pcie-root-port <controller>, for example:
>
> <controller type='pci' index='7' model='pcie-root-port'>
> <model name='pcie-root-port'/>
> <target chassis='7' port='0x15'/>
> <alias name='ua-gfx0'/>
> <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> function='0x5'/>
> </controller>
>
> The "ua-" here is a mandatory prefix. We can then use:
>
> <qemu:commandline>
> <qemu:arg value='-set'/>
> <qemu:arg value='device.ua-gfx0.x-speed=8'/>
> <qemu:arg value='-set'/>
> <qemu:arg value='device.ua-gfx0.x-width=16'/>
> </qemu:commandline>
>
> or, without an alias, set globals such as:
>
> <qemu:commandline>
> <qemu:arg value='-global'/>
> <qemu:arg value='pcie-root-port.x-speed=8'/>
> <qemu:arg value='-global'/>
> <qemu:arg value='pcie-root-port.x-width=16'/>
> </qemu:commandline>
>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Marcel Apfelbaum <marcel.apfelb...@gmail.com>
> Tested-by: Geoffrey McRae <ge...@hostfission.com>
> Signed-off-by: Alex Williamson <alex.william...@redhat.com>
Reviewed-by: Eric Auger <eric.au...@redhat.com>
Thanks
Eric
> ---
> hw/pci-bridge/gen_pcie_root_port.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/hw/pci-bridge/gen_pcie_root_port.c
> b/hw/pci-bridge/gen_pcie_root_port.c
> index 299de429ec1e..ca5418a89dd2 100644
> --- a/hw/pci-bridge/gen_pcie_root_port.c
> +++ b/hw/pci-bridge/gen_pcie_root_port.c
> @@ -124,6 +124,10 @@ static Property gen_rp_props[] = {
> res_reserve.mem_pref_32, -1),
> DEFINE_PROP_SIZE("pref64-reserve", GenPCIERootPort,
> res_reserve.mem_pref_64, -1),
> + DEFINE_PROP_PCIE_LINK_SPEED("x-speed", PCIESlot,
> + speed, PCIE_LINK_SPEED_2_5),
> + DEFINE_PROP_PCIE_LINK_WIDTH("x-width", PCIESlot,
> + width, PCIE_LINK_WIDTH_1),
> DEFINE_PROP_END_OF_LIST()
> };
>
>
>
