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

[Jag Raman]

> On Sep 23, 2020, at 11:10 AM, Michael S. Tsirkin <mst@redhat.com> wrote:
> 
> 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?

Thanks for the comment Michael. We will add a migration blocker from this 
device.

—
Jag

> 
>> ---
>> 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
>