Re: [PATCH v11 04/19] multi-process: setup a machine object for remote device process

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 10/15/20 8:04 PM, Jagannathan Raman wrote:
> remote-machine object sets up various subsystems of the remote
> device process. Instantiate PCI host bridge object and initialize RAM, IO &
> PCI memory regions.
> 
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>   MAINTAINERS                  |  2 ++
>   hw/i386/meson.build          |  1 +
>   hw/i386/remote.c             | 69 ++++++++++++++++++++++++++++++++++++++++++++
>   include/hw/i386/remote.h     | 28 ++++++++++++++++++
>   include/hw/pci-host/remote.h |  1 +
>   5 files changed, 101 insertions(+)
>   create mode 100644 hw/i386/remote.c
>   create mode 100644 include/hw/i386/remote.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index bb1d701..12945ee 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3102,6 +3102,8 @@ M: John G Johnson <john.g.johnson@oracle.com>
>   S: Maintained
>   F: hw/pci-host/remote.c
>   F: include/hw/pci-host/remote.h
> +F: hw/i386/remote.c
> +F: include/hw/i386/remote.h
>   
>   Build and test automation
>   -------------------------
> diff --git a/hw/i386/meson.build b/hw/i386/meson.build
> index e5d109f..d9d4f40 100644
> --- a/hw/i386/meson.build
> +++ b/hw/i386/meson.build
> @@ -24,6 +24,7 @@ i386_ss.add(when: 'CONFIG_PC', if_true: files(
>     'pc_sysfw.c',
>     'acpi-build.c',
>     'port92.c'))
> +i386_ss.add(when: 'CONFIG_MPQEMU', if_true: files('remote.c'))
>   
>   subdir('kvm')
>   subdir('xen')
> diff --git a/hw/i386/remote.c b/hw/i386/remote.c
> new file mode 100644
> index 0000000..a67be33
> --- /dev/null
> +++ b/hw/i386/remote.c
> @@ -0,0 +1,69 @@
> +/*
> + * Machine for remote device
> + *
> + *  This machine type is used by the remote device process in multi-process
> + *  QEMU. QEMU device models depend on parent busses, interrupt controllers,
> + *  memory regions, etc. The remote machine type offers this environment so
> + *  that QEMU device models can be used as remote devices.
> + *
> + * Copyright © 2018, 2020 Oracle and/or its affiliates.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu-common.h"
> +
> +#include "hw/i386/remote.h"
> +#include "exec/address-spaces.h"
> +#include "exec/memory.h"
> +#include "qapi/error.h"
> +
> +static void remote_machine_init(MachineState *machine)
> +{
> +    MemoryRegion *system_memory, *system_io, *pci_memory;
> +    RemoteMachineState *s = REMOTE_MACHINE(machine);
> +    RemotePCIHost *rem_host;
> +
> +    system_memory = get_system_memory();
> +    system_io = get_system_io();
> +
> +    pci_memory = g_new(MemoryRegion, 1);
> +    memory_region_init(pci_memory, NULL, "pci", UINT64_MAX);
> +
> +    rem_host = REMOTE_HOST_DEVICE(qdev_new(TYPE_REMOTE_HOST_DEVICE));
> +
> +    rem_host->mr_pci_mem = pci_memory;
> +    rem_host->mr_sys_mem = system_memory;
> +    rem_host->mr_sys_io = system_io;
> +
> +    s->host = rem_host;
> +
> +    object_property_add_child(OBJECT(s), "remote-device", OBJECT(rem_host));
> +    memory_region_add_subregion_overlap(system_memory, 0x0, pci_memory, -1);
> +
> +    qdev_realize(DEVICE(rem_host), sysbus_get_default(), &error_fatal);
> +}

Nothing is x86-specific in this machine. Why not make it a generic
machine, like the 'none' one?