Re: [Qemu-devel] [PATCH v4 0/7] s390x/pci: Improve zPCI to cover more cases

[Cornelia Huck <cohuck@redhat.com>]

On Thu, 30 Nov 2017 13:55:23 +0100
Pierre Morel <pmorel@linux.vnet.ibm.com> wrote:

> This patch fixes the following BUG:
> Even a guest is able to detect virtio_pci device, the init function
> the Linux virtio_pci driver will hang because zPCI does not support
> the subregions used by virtio_pci.
> 
> It follows that right now the PCI support is very limited
> (e.g. pass through of a host vfio device)
> To enable features like virtio-pci several modifications needs to be
> done.
> 
> As already stated above, Virtio-PCI uses subregions, which may eventually
> be discontinuous inside bars instead of a single flat region often used
> by real devices.
> The address offset being formerly calculated from the BAR base address
> must be adapted to the subregions instead of to the single region.
> 
> This patch provides the new calculation for the three kind of BAR
> access, zPCI STORE, zPCI LOAD and zPCI STORE BLOCK done by zPCI.
> 
> We use the opportunity to
>  - enhance the fault detection for zPCI STORE and LOAD,
>  - enhance the fault detection and to provide the maximum STORE BLOCK
>    block size, maxstbl, for zPCI STORE BLOCK
>  - factor out part of the code used to calculate the offset and
>    access the BARs,
>  - factor out the code for endianess conversion.
> 
> 
> Pierre Morel (7):
>   s390x/pci: factor out endianess conversion
>   s390x/pci: rework PCI STORE
>   s390x/pci: rework PCI LOAD
>   s390x/pci: rework PCI STORE BLOCK
>   s390x/pci: move the memory region read from pcilg
>   s390x/pci: move the memory region write from pcistg
>   s390x/pci: search for subregion inside the BARs
> 
>  hw/s390x/s390-pci-bus.h  |   1 +
>  hw/s390x/s390-pci-inst.c | 251 ++++++++++++++++++++++++++++-------------------
>  hw/s390x/s390-pci-inst.h |   6 +-
>  3 files changed, 158 insertions(+), 100 deletions(-)
> 

I massaged this to fit on top of David's patchset and it still works
fine with my pci/tcg patches.

Some small comments for things I can fix up myself (will reply to
individual patches). On the whole, I'm inclined to queue this.