Re: [PATCH v5 12/50] multi-process: remote process initialization

[Dr. David Alan Gilbert]

* Jagannathan Raman (address@hidden) wrote:
> Adds the handler to process message from QEMU,
> Initialize remote process main loop, handles SYNC_SYSMEM
> message by updating its "system_memory" container using
> shared file descriptors received from QEMU.
> 
> Signed-off-by: John G Johnson <address@hidden>
> Signed-off-by: Elena Ufimtseva <address@hidden>
> Signed-off-by: Jagannathan Raman <address@hidden>
> ---
>  v4 -> v5:
>   - We checked if we could use functions already defined in
>     util/main-loop.c instead of using g_main_loop_run. However,
>     we couldn't find a suitable function that's generic enough
>     to do this. All of them have emulator code embedded in them
>     which is not used by the remote process. We are therefore
>     not making any change to this patch
> 
>  remote/remote-main.c | 85 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 85 insertions(+)
> 
> diff --git a/remote/remote-main.c b/remote/remote-main.c
> index ecf30e0..56315cd 100644
> --- a/remote/remote-main.c
> +++ b/remote/remote-main.c
> @@ -12,6 +12,7 @@
>  #include "qemu-common.h"
>  
>  #include <stdio.h>
> +#include <unistd.h>
>  
>  #include "qemu/module.h"
>  #include "remote/pcihost.h"
> @@ -19,12 +20,96 @@
>  #include "hw/boards.h"
>  #include "hw/qdev-core.h"
>  #include "qemu/main-loop.h"
> +#include "remote/memory.h"
> +#include "io/mpqemu-link.h"
> +#include "qapi/error.h"
> +#include "qemu/main-loop.h"
> +#include "sysemu/cpus.h"
> +#include "qemu-common.h"
> +#include "hw/pci/pci.h"
> +#include "qemu/thread.h"
> +#include "qemu/main-loop.h"
> +#include "qemu/config-file.h"
> +#include "sysemu/sysemu.h"
> +#include "block/block.h"
> +#include "exec/ramlist.h"
> +
> +static MPQemuLinkState *mpqemu_link;
> +PCIDevice *remote_pci_dev;
> +
> +static void process_msg(GIOCondition cond, MPQemuChannel *chan)
> +{
> +    MPQemuMsg *msg = NULL;
> +    Error *err = NULL;
> +
> +    if ((cond & G_IO_HUP) || (cond & G_IO_ERR)) {
> +        goto finalize_loop;
> +    }
> +
> +    msg = g_malloc0(sizeof(MPQemuMsg));
> +
> +    if (mpqemu_msg_recv(msg, chan) < 0) {
> +        error_setg(&err, "Failed to receive message");

Please give error messages more context, e.g. the device or process name
or something like that so that; it helps when we get a user
reporting a crash and they report 'Unknown command' in their log, but
then we have to figure out where to point them.

> +        goto finalize_loop;
> +    }
> +
> +    switch (msg->cmd) {
> +    case INIT:
> +        break;
> +    case PCI_CONFIG_WRITE:
> +        break;
> +    case PCI_CONFIG_READ:
> +        break;
> +    default:
> +        error_setg(&err, "Unknown command");
> +        goto finalize_loop;
> +    }
> +
> +    g_free(msg->data2);
> +    g_free(msg);
> +
> +    return;
> +
> +finalize_loop:
> +    if (err) {
> +        error_report_err(err);
> +    }
> +    g_free(msg);
> +    mpqemu_link_finalize(mpqemu_link);
> +    mpqemu_link = NULL;
> +}
>  
>  int main(int argc, char *argv[])
>  {
> +    Error *err = NULL;
> +
>      module_call_init(MODULE_INIT_QOM);
>  
> +    bdrv_init_with_whitelist();
> +
> +    if (qemu_init_main_loop(&err)) {
> +        error_report_err(err);
> +        return -EBUSY;
> +    }
> +
> +    qemu_init_cpu_loop();
> +
> +    page_size_init();
> +
> +    qemu_mutex_init(&ram_list.mutex);
> +

So these are some subset of the things from qemu_init; I guess
we'll have to be careful when we add stuff to vl.c to think what should
also be added here.

Dave

>      current_machine = 
> MACHINE(REMOTE_MACHINE(object_new(TYPE_REMOTE_MACHINE)));
>  
> +    mpqemu_link = mpqemu_link_create();
> +    if (!mpqemu_link) {
> +        printf("Could not create MPQemu link\n");
> +        return -1;
> +    }
> +
> +    mpqemu_init_channel(mpqemu_link, &mpqemu_link->com, STDIN_FILENO);
> +    mpqemu_link_set_callback(mpqemu_link, process_msg);
> +
> +    mpqemu_start_coms(mpqemu_link);
> +
>      return 0;
>  }
> -- 
> 1.8.3.1
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK