Re: [PATCH 0/5] Legacy direct-assign mode

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Fri, Nov 20, 2020 at 03:51:39PM -0700, Jon Derrick wrote:
> This set adds a legacy direct-assign mode. Newer enterprise hardware has
> physical addressing hints to assist device passthrough to guests that needs to
> correctly program bridge windows with physical addresses. Some customers are
> using a legacy method that relies on the VMD subdevice domain's root port
> windows to be written with the physical addresses. This method also allows
> other hypervisors besides QEMU/KVM to perform guest passthrough.
> 
> This patchset adds a host and guest mode to write the physical address
> information to the root port registers in the host and read them in the guest,
> and restore them in both cases on module unload.
> 
> This patchset also folds in the VMD subdevice domain secondary bus reset
> patchset [1] to clear the domain prior to guest passthrough.
> 
> [1] https://patchwork.kernel.org/project/linux-pci/cover/20200928010557.5324-1-jonathan.derrick@intel.com/
> 
> Jon Derrick (5):
>   PCI: vmd: Reset the VMD subdevice domain on probe
>   PCI: Add a reset quirk for VMD
>   PCI: vmd: Add offset translation helper
>   PCI: vmd: Pass features to vmd_get_phys_offsets()
>   PCI: vmd: Add legacy guest passthrough mode
> 
>  drivers/pci/controller/vmd.c | 200 ++++++++++++++++++++++++++++++++++++++-----
>  drivers/pci/quirks.c         |  48 +++++++++++
>  2 files changed, 227 insertions(+), 21 deletions(-)

Hi Jon,

it is unclear to me where we are with this series, please let me know.

Thanks,
Lorenzo