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Re: [Qemu-devel] [for-4.0 PATCH v3 6/9] pcie: Allow generic PCIe root po
From: |
Auger Eric |
Subject: |
Re: [Qemu-devel] [for-4.0 PATCH v3 6/9] pcie: Allow generic PCIe root port to specify link speed and width |
Date: |
Thu, 6 Dec 2018 12:22:55 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 |
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 <address@hidden>
> Cc: Marcel Apfelbaum <address@hidden>
> Tested-by: Geoffrey McRae <address@hidden>
> Signed-off-by: Alex Williamson <address@hidden>
Reviewed-by: Eric Auger <address@hidden>
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()
> };
>
>
>
- [Qemu-devel] [for-4.0 PATCH v3 0/9] pcie: Enhanced link speed and width support, Alex Williamson, 2018/12/04
- [Qemu-devel] [for-4.0 PATCH v3 4/9] pcie: Add link speed and width fields to PCIESlot, Alex Williamson, 2018/12/04
- [Qemu-devel] [for-4.0 PATCH v3 6/9] pcie: Allow generic PCIe root port to specify link speed and width, Alex Williamson, 2018/12/04
- Re: [Qemu-devel] [for-4.0 PATCH v3 6/9] pcie: Allow generic PCIe root port to specify link speed and width,
Auger Eric <=
- [Qemu-devel] [for-4.0 PATCH v3 7/9] vfio/pci: Remove PCIe Link Status emulation, Alex Williamson, 2018/12/04
- [Qemu-devel] [for-4.0 PATCH v3 9/9] pcie: Fast PCIe root ports for new machines, Alex Williamson, 2018/12/04
- [Qemu-devel] [for-4.0 PATCH v3 5/9] pcie: Fill PCIESlot link fields to support higher speeds and widths, Alex Williamson, 2018/12/04
- [Qemu-devel] [for-4.0 PATCH v3 3/9] qapi: Define PCIe link speed and width properties, Alex Williamson, 2018/12/04