diff mbox series

[v12,12/19] multi-process: introduce proxy object

Message ID 42f53a5af6279581509638b23ca624e560e07f71.1606853298.git.jag.raman@oracle.com (mailing list archive)
State New, archived
Headers show
Series Initial support for multi-process Qemu | expand

Commit Message

Jag Raman Dec. 1, 2020, 8:22 p.m. UTC
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>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/hw/remote/proxy.h | 36 +++++++++++++++++
 hw/remote/proxy.c         | 98 +++++++++++++++++++++++++++++++++++++++++++++++
 MAINTAINERS               |  2 +
 hw/remote/meson.build     |  1 +
 4 files changed, 137 insertions(+)
 create mode 100644 include/hw/remote/proxy.h
 create mode 100644 hw/remote/proxy.c

Comments

Marc-André Lureau Dec. 8, 2020, 12:23 p.m. UTC | #1
Hi

On Wed, Dec 2, 2020 at 12:23 AM Jagannathan Raman <jag.raman@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>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  include/hw/remote/proxy.h | 36 +++++++++++++++++
>  hw/remote/proxy.c         | 98
> +++++++++++++++++++++++++++++++++++++++++++++++
>  MAINTAINERS               |  2 +
>  hw/remote/meson.build     |  1 +
>  4 files changed, 137 insertions(+)
>  create mode 100644 include/hw/remote/proxy.h
>  create mode 100644 hw/remote/proxy.c
>
> diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
> new file mode 100644
> index 0000000..923432a
> --- /dev/null
> +++ b/include/hw/remote/proxy.h
> @@ -0,0 +1,36 @@
> +/*
> + * 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 "x-pci-proxy-dev"
> +
> +#define PCI_PROXY_DEV(obj) \
> +            OBJECT_CHECK(PCIProxyDev, (obj), TYPE_PCI_PROXY_DEV)
> +typedef struct PCIProxyDev PCIProxyDev;
> +
> +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;
> +    Error *migration_blocker;
> +};
> +
> +#endif /* PROXY_H */
> diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
> new file mode 100644
> index 0000000..29100bc
> --- /dev/null
> +++ b/hw/remote/proxy.c
> @@ -0,0 +1,98 @@
> +/*
> + * 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/remote/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"
> +#include "migration/blocker.h"
> +
> +static void proxy_set_socket(PCIProxyDev *pdev, int fd, Error **errp)
> +{
> +    pdev->ioc = qio_channel_new_fd(fd, errp);
> +}
>

That one line function (called once) should be inlined.

+
> +static Property proxy_properties[] = {
> +    DEFINE_PROP_STRING("fd", PCIProxyDev, fd),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
>

Generally we put properties just above class_init, where it is used.

+static void pci_proxy_dev_realize(PCIDevice *device, Error **errp)
> +{
>

(errp shouldn't be NULL, but ERRP_GUARD would be safer)

+    PCIProxyDev *dev = PCI_PROXY_DEV(device);
> +    int fd;
> +
> +    if (dev->fd) {
> +        fd = monitor_fd_param(monitor_cur(), 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;
>

We prefer early return, to keep the code easy to read.

if (!dev->fd) {
  return error...
}

the_normal_thing();
...

+    }
> +
> +    error_setg(&dev->migration_blocker, "%s does not support migration",
> +               TYPE_PCI_PROXY_DEV);
> +    if (migrate_add_blocker(dev->migration_blocker, errp)) {
> +        error_free(dev->migration_blocker);
>

leave that free to dev_exit() ?


> +        error_free(*errp);
> +        dev->migration_blocker = NULL;
> +        error_setg(errp, "Failed to set migration blocker");
>

Why not use the error from migrate_add_blocker?

+    }
> +
> +    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);
>

on early return in realize, dev->ioc is NULL. This will crash.


+
> +    migrate_del_blocker(dev->migration_blocker);
>

So is migration_blocker, but this should be safe with NULL


> +
> +    error_free(dev->migration_blocker);
>
+}
> +
> +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/MAINTAINERS b/MAINTAINERS
> index 24cb36e..ebd1d1d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -3148,6 +3148,8 @@ F: include/hw/remote/remote-obj.h
>  F: hw/remote/remote-obj.c
>  F: include/hw/remote/memory.h
>  F: hw/remote/memory.c
> +F: hw/remote/proxy.c
> +F: include/hw/remote/proxy.h
>
>  Build and test automation
>  -------------------------
> diff --git a/hw/remote/meson.build b/hw/remote/meson.build
> index 64da16c..569cd20 100644
> --- a/hw/remote/meson.build
> +++ b/hw/remote/meson.build
> @@ -4,6 +4,7 @@ remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true:
> files('machine.c'))
>  remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true:
> files('mpqemu-link.c'))
>  remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
>  remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
> +remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
>
>  specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))
>
> --
> 1.8.3.1
>
>
diff mbox series

Patch

diff --git a/include/hw/remote/proxy.h b/include/hw/remote/proxy.h
new file mode 100644
index 0000000..923432a
--- /dev/null
+++ b/include/hw/remote/proxy.h
@@ -0,0 +1,36 @@ 
+/*
+ * 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 "x-pci-proxy-dev"
+
+#define PCI_PROXY_DEV(obj) \
+            OBJECT_CHECK(PCIProxyDev, (obj), TYPE_PCI_PROXY_DEV)
+typedef struct PCIProxyDev PCIProxyDev;
+
+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;
+    Error *migration_blocker;
+};
+
+#endif /* PROXY_H */
diff --git a/hw/remote/proxy.c b/hw/remote/proxy.c
new file mode 100644
index 0000000..29100bc
--- /dev/null
+++ b/hw/remote/proxy.c
@@ -0,0 +1,98 @@ 
+/*
+ * 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/remote/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"
+#include "migration/blocker.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(monitor_cur(), 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;
+    }
+
+    error_setg(&dev->migration_blocker, "%s does not support migration",
+               TYPE_PCI_PROXY_DEV);
+    if (migrate_add_blocker(dev->migration_blocker, errp)) {
+        error_free(dev->migration_blocker);
+        error_free(*errp);
+        dev->migration_blocker = NULL;
+        error_setg(errp, "Failed to set migration blocker");
+    }
+
+    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);
+
+    migrate_del_blocker(dev->migration_blocker);
+
+    error_free(dev->migration_blocker);
+}
+
+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/MAINTAINERS b/MAINTAINERS
index 24cb36e..ebd1d1d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3148,6 +3148,8 @@  F: include/hw/remote/remote-obj.h
 F: hw/remote/remote-obj.c
 F: include/hw/remote/memory.h
 F: hw/remote/memory.c
+F: hw/remote/proxy.c
+F: include/hw/remote/proxy.h
 
 Build and test automation
 -------------------------
diff --git a/hw/remote/meson.build b/hw/remote/meson.build
index 64da16c..569cd20 100644
--- a/hw/remote/meson.build
+++ b/hw/remote/meson.build
@@ -4,6 +4,7 @@  remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('machine.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('mpqemu-link.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('message.c'))
 remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('remote-obj.c'))
+remote_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('proxy.c'))
 
 specific_ss.add(when: 'CONFIG_MULTIPROCESS', if_true: files('memory.c'))