Re: [PATCH 1/1] virtio-pci: fix memory_region_find for VirtIOPCIRegion's MR

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Sep 24, 2024 at 02:31:20PM +0200, David Hildenbrand wrote:
> On 24.09.24 03:11, Gao Shiyuan wrote:
> 
> Make sure to version your patch series. For example, via
> 	$ git format-patch -v1 ...
> 
> > As shown below, if a virtio PCI device is attached under a pci-bridge, the MR
> > of VirtIOPCIRegion does not belong to any address space. So memory_region_find
> > cannot be used to search for this MR.
> 
> I'm starting to wonder if memory_region_find() is really the right fun
> 
> > 
> > Introduce the virtio-pci and pci_bridge_pci address spaces to solve this problem.
> > 
> > Before:
> > memory-region: pci_bridge_pci
> >    0000000000000000-ffffffffffffffff (prio 0, i/o): pci_bridge_pci
> >      00000000fe200000-00000000fe200fff (prio 1, i/o): virtio-blk-pci-msix
> >        00000000fe200000-00000000fe20016f (prio 0, i/o): msix-table
> >        00000000fe200800-00000000fe200807 (prio 0, i/o): msix-pba
> >      000000a000400000-000000a000403fff (prio 1, i/o): virtio-pci
> >        000000a000400000-000000a000400fff (prio 0, i/o): virtio-pci-common-virtio-blk
> >        000000a000401000-000000a000401fff (prio 0, i/o): virtio-pci-isr-virtio-blk
> >        000000a000402000-000000a000402fff (prio 0, i/o): virtio-pci-device-virtio-blk
> >        000000a000403000-000000a000403fff (prio 0, i/o): virtio-pci-notify-virtio-blk
> > 
> > After:
> > address-space: pci_bridge_pci
> >    0000000000000000-ffffffffffffffff (prio 0, i/o): pci_bridge_pci
> >      00000000fe200000-00000000fe200fff (prio 1, i/o): virtio-blk-pci-msix
> >        00000000fe200000-00000000fe20016f (prio 0, i/o): msix-table
> >        00000000fe200800-00000000fe200807 (prio 0, i/o): msix-pba
> >      000000a000400000-000000a000403fff (prio 1, i/o): virtio-pci
> >        000000a000400000-000000a000400fff (prio 0, i/o): virtio-pci-common-virtio-blk
> >        000000a000401000-000000a000401fff (prio 0, i/o): virtio-pci-isr-virtio-blk
> >        000000a000402000-000000a000402fff (prio 0, i/o): virtio-pci-device-virtio-blk
> >        000000a000403000-000000a000403fff (prio 0, i/o): virtio-pci-notify-virtio-blk
> > 
> > address-space: virtio-pci
> >    000000a000400000-000000a000403fff (prio 1, i/o): virtio-pci
> >      000000a000400000-000000a000400fff (prio 0, i/o): virtio-pci-common-virtio-blk
> >      000000a000401000-000000a000401fff (prio 0, i/o): virtio-pci-isr-virtio-blk
> >      000000a000402000-000000a000402fff (prio 0, i/o): virtio-pci-device-virtio-blk
> >      000000a000403000-000000a000403fff (prio 0, i/o): virtio-pci-notify-virtio-blk
> > 
> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2576
> > Fixes: ffa8a3e ("virtio-pci: Add lookup subregion of VirtIOPCIRegion MR")
> 
> Commit id is not unique. Use 12 digits please.
> 
> I'm still not quite sure if memory_region_find() is really the right thing
> to use here, but I'm no expert on that so I'm hoping virtio/PCI people can
> review.

I donnu, what would you use?


> -- 
> Cheers,
> 
> David / dhildenb