| Message ID | 20220814153220.2439468-1-heinrich.schuchardt@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/1] docs: pcie: describe PCIe option ROMs | expand |
On 8/14/22 17:32, Heinrich Schuchardt wrote: > Provide a descriptions of the options that control the emulation of option > ROMS for PCIe devices. > > Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> > --- > v2: > correct description of rombar property > use romfile= to suppress option ROM loading > --- > docs/pcie.txt | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/docs/pcie.txt b/docs/pcie.txt > index 89e3502075..b60f189bd4 100644 > --- a/docs/pcie.txt > +++ b/docs/pcie.txt > @@ -292,6 +292,34 @@ PCI-PCI Bridge slots can be used for legacy PCI host devices. > If you can see the "Express Endpoint" capability in the > output, then the device is indeed PCI Express. > > +8. Option ROM > +============= > +PCIe devices may provide an option ROM. The following properties control the > +emulation of the option ROM: > + > +``rombar`` (default: ``1``) > + For vfio-pci devices a vendor and product ID based denylist exists which > + controls if an available option ROM shall be probed. The 'rombar' option > + allows to override this setting. The value is used as follows: > + 0 = skip probing, 1 = force probing > + > +``romfile`` > + Defines the name of the file to be loaded as option ROM. > + The file size may neither exceed 2 GiB nor ``romsize``. > + Some devices like virtio-net-pci define a default file name. > + > +``romsize`` (default: ``-1``) > + Specifies the size of the option ROM in bytes. The value must be either > + ``-1`` or a power of two. ``-1`` signifies unlimited size. > + > +Some QEMU PCIe devices like virtio-net-pci use an option ROM by default. In the > +following example the option ROM of a virtio-net-pci device is disabled by > +specifying an empty ``romfile`` property. This is useful for architectures where > +QEMU does not supply an option ROM file. > + > +.. code-block:: console > + > + -device virtio-net-pci,netdev=eth1,mq=on,romfile= > > 7. Virtio devices > ================= Hello Michael, hello Marcel, Unfortunately the patch was never reviewed. The patch is available at: https://lore.kernel.org/qemu-devel/20220814153220.2439468-1-heinrich.schuchardt@canonical.com/ https://patchwork.kernel.org/project/qemu-devel/patch/20220814153220.2439468-1-heinrich.schuchardt@canonical.com/ Best regards Heinrich
diff --git a/docs/pcie.txt b/docs/pcie.txt index 89e3502075..b60f189bd4 100644 --- a/docs/pcie.txt +++ b/docs/pcie.txt @@ -292,6 +292,34 @@ PCI-PCI Bridge slots can be used for legacy PCI host devices. If you can see the "Express Endpoint" capability in the output, then the device is indeed PCI Express. +8. Option ROM +============= +PCIe devices may provide an option ROM. The following properties control the +emulation of the option ROM: + +``rombar`` (default: ``1``) + For vfio-pci devices a vendor and product ID based denylist exists which + controls if an available option ROM shall be probed. The 'rombar' option + allows to override this setting. The value is used as follows: + 0 = skip probing, 1 = force probing + +``romfile`` + Defines the name of the file to be loaded as option ROM. + The file size may neither exceed 2 GiB nor ``romsize``. + Some devices like virtio-net-pci define a default file name. + +``romsize`` (default: ``-1``) + Specifies the size of the option ROM in bytes. The value must be either + ``-1`` or a power of two. ``-1`` signifies unlimited size. + +Some QEMU PCIe devices like virtio-net-pci use an option ROM by default. In the +following example the option ROM of a virtio-net-pci device is disabled by +specifying an empty ``romfile`` property. This is useful for architectures where +QEMU does not supply an option ROM file. + +.. code-block:: console + + -device virtio-net-pci,netdev=eth1,mq=on,romfile= 7. Virtio devices =================
Provide a descriptions of the options that control the emulation of option ROMS for PCIe devices. Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com> --- v2: correct description of rombar property use romfile= to suppress option ROM loading --- docs/pcie.txt | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)