Re: [PATCH v9 11/20] multi-process: introduce proxy object

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

On Thu, Aug 27, 2020 at 11:12:22AM -0700, elena.ufimtseva@oracle.com wrote:
> From: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> 
> Defines a PCI Device proxy object as a child of TYPE_PCI_DEVICE.
> 
> Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
> Signed-off-by: John G Johnson <john.g.johnson@oracle.com>


Hmm I think this device needs to block migration. And maybe the pci host
device needs to do it too?

> ---
>  MAINTAINERS            |  2 +
>  hw/pci/meson.build     |  1 +
>  hw/pci/proxy.c         | 84 ++++++++++++++++++++++++++++++++++++++++++
>  include/hw/pci/proxy.h | 34 +++++++++++++++++
>  4 files changed, 121 insertions(+)
>  create mode 100644 hw/pci/proxy.c
>  create mode 100644 include/hw/pci/proxy.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 14b8c005fc..7b2096b300 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3052,6 +3052,8 @@ F: include/hw/i386/remote-obj.h
>  F: hw/i386/remote-obj.c
>  F: include/hw/i386/remote-memory.h
>  F: hw/i386/remote-memory.c
> +F: hw/pci/proxy.c
> +F: include/hw/pci/proxy.h
>  
>  Build and test automation
>  -------------------------
> diff --git a/hw/pci/meson.build b/hw/pci/meson.build
> index 5c4bbac817..0df30172b5 100644
> --- a/hw/pci/meson.build
> +++ b/hw/pci/meson.build
> @@ -12,6 +12,7 @@ pci_ss.add(files(
>  # allow plugging PCIe devices into PCI buses, include them even if
>  # CONFIG_PCI_EXPRESS=n.
>  pci_ss.add(files('pcie.c', 'pcie_aer.c'))
> +pci_ss.add(when: 'CONFIG_MPQEMU', if_true: files('proxy.c'))
>  softmmu_ss.add(when: 'CONFIG_PCI_EXPRESS', if_true: files('pcie_port.c', 'pcie_host.c'))
>  softmmu_ss.add_all(when: 'CONFIG_PCI', if_true: pci_ss)
>  
> diff --git a/hw/pci/proxy.c b/hw/pci/proxy.c
> new file mode 100644
> index 0000000000..1bff744bd6
> --- /dev/null
> +++ b/hw/pci/proxy.c
> @@ -0,0 +1,84 @@
> +/*
> + * 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/pci/proxy.h"
> +#include "hw/pci/pci.h"
> +#include "qapi/error.h"
> +#include "io/channel-util.h"
> +#include "hw/qdev-properties.h"
> +#include "monitor/monitor.h"
> +
> +static void proxy_set_socket(PCIProxyDev *pdev, int fd, Error **errp)
> +{
> +    pdev->ioc = qio_channel_new_fd(fd, errp);
> +}
> +
> +static Property proxy_properties[] = {
> +    DEFINE_PROP_STRING("fd", PCIProxyDev, fd),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
> +{
> +    PCIProxyDev *dev = PCI_PROXY_DEV(device);
> +    int fd;
> +
> +    if (dev->fd) {
> +        fd = monitor_fd_param(cur_mon, dev->fd, errp);
> +        if (fd == -1) {
> +            error_prepend(errp, "proxy: unable to parse fd: ");
> +            return;
> +        }
> +        proxy_set_socket(dev, fd, errp);
> +    } else {
> +        error_setg(errp, "fd parameter not specified for %s",
> +                   DEVICE(device)->id);
> +        return;
> +    }
> +
> +    qemu_mutex_init(&dev->io_mutex);
> +    qio_channel_set_blocking(dev->ioc, true, NULL);
> +}
> +
> +static void pci_proxy_dev_exit(PCIDevice *pdev)
> +{
> +    PCIProxyDev *dev = PCI_PROXY_DEV(pdev);
> +
> +    qio_channel_close(dev->ioc, NULL);
> +}
> +
> +static void pci_proxy_dev_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> +
> +    k->realize = pci_proxy_dev_realize;
> +    k->exit = pci_proxy_dev_exit;
> +    device_class_set_props(dc, proxy_properties);
> +}
> +
> +static const TypeInfo pci_proxy_dev_type_info = {
> +    .name          = TYPE_PCI_PROXY_DEV,
> +    .parent        = TYPE_PCI_DEVICE,
> +    .instance_size = sizeof(PCIProxyDev),
> +    .class_init    = pci_proxy_dev_class_init,
> +    .interfaces = (InterfaceInfo[]) {
> +        { INTERFACE_CONVENTIONAL_PCI_DEVICE },
> +        { },
> +    },
> +};
> +
> +static void pci_proxy_dev_register_types(void)
> +{
> +    type_register_static(&pci_proxy_dev_type_info);
> +}
> +
> +type_init(pci_proxy_dev_register_types)
> diff --git a/include/hw/pci/proxy.h b/include/hw/pci/proxy.h
> new file mode 100644
> index 0000000000..4ae7becf34
> --- /dev/null
> +++ b/include/hw/pci/proxy.h
> @@ -0,0 +1,34 @@
> +/*
> + * 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.
> + *
> + */
> +
> +#ifndef PROXY_H
> +#define PROXY_H
> +
> +#include "hw/pci/pci.h"
> +#include "io/channel.h"
> +
> +#define TYPE_PCI_PROXY_DEV "pci-proxy-dev"
> +
> +#define PCI_PROXY_DEV(obj) \
> +            OBJECT_CHECK(PCIProxyDev, (obj), TYPE_PCI_PROXY_DEV)
> +
> +typedef struct PCIProxyDev {
> +    PCIDevice parent_dev;
> +    char *fd;
> +
> +    /*
> +     * Mutex used to protect the QIOChannel fd from
> +     * the concurrent access by the VCPUs since proxy
> +     * blocks while awaiting for the replies from the
> +     * process remote.
> +     */
> +    QemuMutex io_mutex;
> +    QIOChannel *ioc;
> +} PCIProxyDev;
> +
> +#endif /* PROXY_H */
> -- 
> 2.25.GIT