On Wed, Sep 25, 2024 8:58 PM Junjie Mao wrote: > > 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. > > > > 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") > > > > Signed-off-by: Gao Shiyuan <gaoshiy...@baidu.com> > > Signed-off-by: Zuo Boqun <zuobo...@baidu.com> > > --- > > hw/pci/pci_bridge.c | 2 ++ > > hw/virtio/virtio-pci.c | 3 +++ > > include/hw/pci/pci_bridge.h | 1 + > > include/hw/virtio/virtio-pci.h | 1 + > > 4 files changed, 7 insertions(+) > > > > diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c index > > 6a4e38856d..74683e7445 100644 > > --- a/hw/pci/pci_bridge.c > > +++ b/hw/pci/pci_bridge.c > > @@ -380,6 +380,7 @@ void pci_bridge_initfn(PCIDevice *dev, const char > *typename) > > sec_bus->map_irq = br->map_irq ? br->map_irq : > pci_swizzle_map_irq_fn; > > sec_bus->address_space_mem = &br->address_space_mem; > > memory_region_init(&br->address_space_mem, OBJECT(br), > > "pci_bridge_pci", UINT64_MAX); > > + address_space_init(&br->as_mem, &br->address_space_mem, > > + "pci_bridge_pci"); > > I don't think this "pci_bridge_pci" address space is necessary. The > VirtIOPCIProxy.modern_as AddressSpace is sufficient for > memory_region_add() to work.
This is because memory_region_find_rcu () and memory_region_to_address_space() will find the memory container on the top level and then get the corresponding address space of it. If we only add "VirtIOPCIProxy.modern_as AddressSpace", memory_region_find() still cannot find a address space. Because "pci_bridge_pci" is the memory container on top level and it doesn't have a corresponding address space.
