Re: [PATCH v2 1/1] virtio-pci: fix memory_region_find for VirtIOPCIRegion's MR

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Oct 09, 2024 at 05:58:27PM +0800, Gao Shiyuan via 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 address spaces to solve this problem.
> 
> Before:
> memory-region: pci_bridge_pci
>   0000000000000000-ffffffffffffffff (prio 0, i/o): pci_bridge_pci
>     00000000fe840000-00000000fe840fff (prio 1, i/o): virtio-net-pci-msix
>       00000000fe840000-00000000fe84003f (prio 0, i/o): msix-table
>       00000000fe840800-00000000fe840807 (prio 0, i/o): msix-pba
>     0000380000000000-0000380000003fff (prio 1, i/o): virtio-pci
>       0000380000000000-0000380000000fff (prio 0, i/o): virtio-pci-common-virtio-net
>       0000380000001000-0000380000001fff (prio 0, i/o): virtio-pci-isr-virtio-net
>       0000380000002000-0000380000002fff (prio 0, i/o): virtio-pci-device-virtio-net
>       0000380000003000-0000380000003fff (prio 0, i/o): virtio-pci-notify-virtio-net
> 
> After:
> address-space: virtio-pci-cfg-mem-as
>   0000380000000000-0000380000003fff (prio 1, i/o): virtio-pci
>     0000380000000000-0000380000000fff (prio 0, i/o): virtio-pci-common-virtio-net
>     0000380000001000-0000380000001fff (prio 0, i/o): virtio-pci-isr-virtio-net
>     0000380000002000-0000380000002fff (prio 0, i/o): virtio-pci-device-virtio-net
>     0000380000003000-0000380000003fff (prio 0, i/o): virtio-pci-notify-virtio-net
> 
> address-space: pci_bridge_pci_mem
>   0000000000000000-ffffffffffffffff (prio 0, i/o): pci_bridge_pci
>     00000000fe840000-00000000fe840fff (prio 1, i/o): virtio-net-pci-msix
>       00000000fe840000-00000000fe84003f (prio 0, i/o): msix-table
>       00000000fe840800-00000000fe840807 (prio 0, i/o): msix-pba
>     0000380000000000-0000380000003fff (prio 1, i/o): virtio-pci
>       0000380000000000-0000380000000fff (prio 0, i/o): virtio-pci-common-virtio-net
>       0000380000001000-0000380000001fff (prio 0, i/o): virtio-pci-isr-virtio-net
>       0000380000002000-0000380000002fff (prio 0, i/o): virtio-pci-device-virtio-net
>       0000380000003000-0000380000003fff (prio 0, i/o): virtio-pci-notify-virtio-net
> 
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2576
> Fixes: ffa8a3e3b2e6 ("virtio-pci: Add lookup subregion of VirtIOPCIRegion MR")
> 
> Signed-off-by: Gao Shiyuan <gaoshiyuan@baidu.com>
> Signed-off-by: Zuo Boqun <zuoboqun@baidu.com>
> Signed-off-by: Wang Liang <wangliang44@baidu.com>
> ---
>  hw/pci/pci_bridge.c            | 4 ++++
>  hw/virtio/virtio-pci.c         | 5 +++++
>  include/hw/pci/pci_bridge.h    | 2 ++
>  include/hw/virtio/virtio-pci.h | 3 +++
>  4 files changed, 14 insertions(+)

Should we add some qtest coverage for this perhaps. eg per
the bug report, something like this should demonstrate the
crash:

  static void test_addr_space_crash(void)
  {
    QTestState *s = qtest_init("-device virtio-balloon -machine q35 -nodefaults");

    qtest_outl(s, 0xcf8, 0x80000890);
    qtest_outl(s, 0xcfc, 0x2);
    qtest_outl(s, 0xcf8, 0x80000891);
    qtest_inl(s, 0xcfc);
    qtest_quit(s);
  }


if we add that to one of the tests/qtest/*.c files as appropriate, or
create a new qtest file ?

With regards,
Daniel
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