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Re: [Qemu-devel] [multiprocess RFC PATCH 21/37] multi-process: QMP/HMP c
From: |
Elena Ufimtseva |
Subject: |
Re: [Qemu-devel] [multiprocess RFC PATCH 21/37] multi-process: QMP/HMP commands to add a device to the remote process |
Date: |
Fri, 8 Mar 2019 11:45:51 -0800 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
On Thu, Mar 07, 2019 at 10:39:54AM +0000, Dr. David Alan Gilbert wrote:
> * address@hidden (address@hidden) wrote:
> > From: Jagannathan Raman <address@hidden>
> >
> > Adds rdevice_add QMP & HMP commands to hotplug device to a remote device.
> >
> > Signed-off-by: Jagannathan Raman <address@hidden>
> > Signed-off-by: John G Johnson <address@hidden>
> > Signed-off-by: Elena Ufimtseva <address@hidden>
> > ---
> > hmp-commands.hx | 14 ++++++++
> > hmp.h | 1 +
> > hw/proxy/monitor.c | 92
> > +++++++++++++++++++++++++++++++++++++++++++++++++
> > include/io/proxy-link.h | 2 ++
> > include/monitor/qdev.h | 4 +++
> > monitor.c | 5 +++
> > qapi/misc.json | 22 ++++++++++++
> > remote/remote-main.c | 48 ++++++++++++++++++++++++++
> > 8 files changed, 188 insertions(+)
> >
> > diff --git a/hmp-commands.hx b/hmp-commands.hx
> > index fb3c8ba..7e8e8ab 100644
> > --- a/hmp-commands.hx
> > +++ b/hmp-commands.hx
> > @@ -727,6 +727,20 @@ ETEXI
> >
> > #if defined(CONFIG_MPQEMU)
> > {
> > + .name = "rdevice_add",
> > + .args_type = "rdev_id:s,driver:s,id:s,drive:s,bus:s",
> > + .params = "rdev_id driver id drive bus",
> > + .help = "add device to remote proc, like -rdevice on the
> > command line",
> > + .cmd = hmp_rdevice_add,
> > + },
> > +
> > +STEXI
> > address@hidden rdevice_add @var{config}
> > address@hidden rdevice_add
> > +Add device to remote proc.
> > +ETEXI
> > +
> > + {
> > .name = "remote_proc_list",
> > .args_type = "",
> > .params = "",
> > diff --git a/hmp.h b/hmp.h
> > index 0940634..355a27e 100644
> > --- a/hmp.h
> > +++ b/hmp.h
> > @@ -150,5 +150,6 @@ void hmp_info_vm_generation_id(Monitor *mon, const
> > QDict *qdict);
> > void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
> > void hmp_info_sev(Monitor *mon, const QDict *qdict);
> > void hmp_remote_proc_list(Monitor *mon, const QDict *qdict);
> > +void hmp_rdevice_add(Monitor *mon, const QDict *qdict);
> >
> > #endif
> > diff --git a/hw/proxy/monitor.c b/hw/proxy/monitor.c
> > index 3005eec..2e2cda0 100644
> > --- a/hw/proxy/monitor.c
> > +++ b/hw/proxy/monitor.c
> > @@ -23,6 +23,7 @@
> > */
> >
> > #include <sys/types.h>
> > +#include <string.h>
> >
> > #include "qemu/osdep.h"
> > #include "qapi/qapi-types-block-core.h"
> > @@ -33,6 +34,13 @@
> > #include "hw/boards.h"
> > #include "hw/i386/pc.h"
> > #include "hw/proxy/qemu-proxy.h"
> > +#include "qapi/qapi-commands-misc.h"
> > +#include "monitor/qdev.h"
> > +#include "qapi/qmp/qdict.h"
> > +#include "qapi/qmp/qjson.h"
> > +#include "qapi/qmp/qstring.h"
> > +#include "qapi/error.h"
> > +#include "io/proxy-link.h"
> >
> > /*
> > * TODO: Is there a callback where the allocated memory for QMP could be
> > free'd
> > @@ -87,3 +95,87 @@ void hmp_remote_proc_list(Monitor *mon, const QDict
> > *qdict)
> > pdev->remote_pid, pdev->rid, id, k->command);
> > }
> > }
> > +
> > +static PCIProxyDev *get_proxy_device(QDict *qdict, Error **errp)
> > +{
> > + PCMachineState *pcms = PC_MACHINE(current_machine);
> > + PCIProxyDev *pdev = NULL;
> > + const char *rdev_id;
> > +
> > + if (!qdict_haskey(qdict, "rdev_id")) {
> > + error_setg(errp, "Please specify a value for rdev_id");
> > + return NULL;
> > + }
> > +
> > + rdev_id = qdict_get_str(qdict, "rdev_id");
> > +
> > + pdev = (PCIProxyDev *)g_hash_table_lookup(pcms->remote_devs, rdev_id);
> > + if (!pdev) {
> > + error_setg(errp,
> > + "No remote device by ID %s. Use query-remote command to
> > get remote devices",
> > + rdev_id);
> > + }
> > +
> > + return pdev;
> > +}
> > +
> > +static void rdevice_add_del(QDict *qdict, proc_cmd_t cmd, Error **errp)
> > +{
> > + PCMachineState *pcms = PC_MACHINE(current_machine);
> > + ProcMsg msg = {0};
> > + PCIProxyDev *pdev = NULL;
> > + const char *id;
> > + QString *json;
> > + int wait;
> > +
> > + pdev = get_proxy_device(qdict, errp);
> > + if (*errp) {
> > + return;
> > + }
> > +
> > + qdict_del(qdict, "rdev_id");
> > +
> > + id = qdict_get_str(qdict, "id");
> > +
> > + json = qobject_to_json(QOBJECT(qdict));
> > +
> > + wait = GET_REMOTE_WAIT;
> > +
> > + msg.cmd = cmd;
> > + msg.bytestream = 1;
> > + msg.size = strlen(qstring_get_str(json));
> > + msg.data2 = (uint8_t *)qstring_get_str(json);
> > + msg.num_fds = 1;
> > + msg.fds[0] = wait;
> > +
> > + proxy_proc_send(pdev->proxy_link, &msg);
> > + (void)wait_for_remote(wait);
> > + PUT_REMOTE_WAIT(wait);
>
Hi David
Thanks for your comments.
> Can this not fail? For example what happens if the external
> process dies just about here?
We did not take care yet of these scenarios. Probably polling on the
file descriptor with a timeout will help with this.
This will be addressed in the next patchset.
>
> > + qstring_destroy_obj(QOBJECT(json));
>
> All of this:
> build some JSON
> send it to the remote
> wait for the response
>
> all looks like something more generic than a device add/del - separate
> function?
Agree, that does look like it can be generalized.
>
> > + /* TODO: Only on success */
> > + if (cmd == DEVICE_ADD) {
> > + (void)g_hash_table_insert(pcms->remote_devs,
> > (gpointer)g_strdup(id),
> > + (gpointer)pdev);
> > + }
> > +}
> > +
> > +void qmp_rdevice_add(QDict *qdict, QObject **ret_data, Error **errp)
> > +{
> > + rdevice_add_del(qdict, DEVICE_ADD, errp);
> > +}
> > +
> > +void hmp_rdevice_add(Monitor *mon, const QDict *qdict)
> > +{
> > + Error *err = NULL;
> > +
> > + /* TODO: Is it OK to modify the QDict argument from HMP? */
> > + rdevice_add_del((QDict *)qdict, DEVICE_ADD, &err);
> > +
> > + if (err) {
> > + monitor_printf(mon, "rdevice_add error: %s\n",
> > + error_get_pretty(err));
> > + error_free(err);
> > + }
> > +}
> > diff --git a/include/io/proxy-link.h b/include/io/proxy-link.h
> > index 175e2f1..8781508 100644
> > --- a/include/io/proxy-link.h
> > +++ b/include/io/proxy-link.h
> > @@ -60,6 +60,7 @@ typedef struct ProxyLinkState ProxyLinkState;
> > * BAR_READ Reads from PCI BAR region
> > * SET_IRQFD Sets the IRQFD to be used to raise interrupts directly
> > * from remote device
> > + * DEVICE_ADD QMP/HMP command to hotplug device
> > *
> > */
> > typedef enum {
> > @@ -70,6 +71,7 @@ typedef enum {
> > BAR_WRITE,
> > BAR_READ,
> > SET_IRQFD,
> > + DEVICE_ADD,
> > MAX,
> > } proc_cmd_t;
> >
> > diff --git a/include/monitor/qdev.h b/include/monitor/qdev.h
> > index 0ff3331..065701c 100644
> > --- a/include/monitor/qdev.h
> > +++ b/include/monitor/qdev.h
> > @@ -10,6 +10,10 @@ void hmp_info_qdm(Monitor *mon, const QDict *qdict);
> > void hmp_info_qom_tree(Monitor *mon, const QDict *dict);
> > void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp);
> >
> > +#ifdef CONFIG_MPQEMU
> > +void qmp_rdevice_add(QDict *qdict, QObject **ret_data, Error **errp);
> > +#endif
> > +
>
> I don't think you need to bother ifdef'ing the headers
Ah, that's right, not needed.
>
> > int qdev_device_help(QemuOpts *opts);
> > DeviceState *qdev_device_add(QemuOpts *opts, Error **errp);
> > void qdev_set_id(DeviceState *dev, const char *id);
> > diff --git a/monitor.c b/monitor.c
> > index defa129..0ad52e5 100644
> > --- a/monitor.c
> > +++ b/monitor.c
> > @@ -1155,6 +1155,11 @@ static void monitor_init_qmp_commands(void)
> > qmp_register_command(&qmp_commands, "netdev_add", qmp_netdev_add,
> > QCO_NO_OPTIONS);
> >
> > +#ifdef CONFIG_MPQEMU
> > + qmp_register_command(&qmp_commands, "rdevice_add", qmp_rdevice_add,
> > + QCO_NO_OPTIONS);
> > +#endif
> > +
> > QTAILQ_INIT(&qmp_cap_negotiation_commands);
> > qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
> > qmp_marshal_qmp_capabilities,
> > QCO_ALLOW_PRECONFIG);
> > diff --git a/qapi/misc.json b/qapi/misc.json
> > index 8b3ca4f..28d49ea 100644
> > --- a/qapi/misc.json
> > +++ b/qapi/misc.json
> > @@ -1663,6 +1663,28 @@
> > 'gen': false } # so we can get the additional arguments
> >
> > ##
> > +# @rdevice_add:
> > +#
> > +# @rdev_id: ID of the remote device root
> > +#
> > +# @driver: the name of the new device's driver
> > +#
> > +# @bus: the device's parent bus (device tree path)
> > +#
> > +# @id: the device's ID, must be unique
> > +#
> > +# Additional arguments depend on the type.
> > +#
> > +# Add a device.
> > +#
> > +# Since: 3.0
> > +##
> > +{ 'command': 'rdevice_add',
> > + 'data': {'rdev_id': 'str', 'driver': 'str', '*bus': 'str', '*id': 'str'},
> > + 'if': 'defined(CONFIG_MPQEMU)',
> > + 'gen': false } # so we can get the additional arguments
> > +
> > +##
> > # @device_del:
> > #
> > # Remove a device from a guest
> > diff --git a/remote/remote-main.c b/remote/remote-main.c
> > index 4683e7d..03c14de 100644
> > --- a/remote/remote-main.c
> > +++ b/remote/remote-main.c
> > @@ -48,6 +48,11 @@
> > #include "exec/memattrs.h"
> > #include "exec/address-spaces.h"
> > #include "remote/iohub.h"
> > +#include "qapi/qmp/qjson.h"
> > +#include "qapi/qmp/qobject.h"
> > +#include "qemu/option.h"
> > +#include "qemu/config-file.h"
> > +#include "monitor/qdev.h"
> >
> > static ProxyLinkState *proxy_link;
> > PCIDevice *remote_pci_dev;
> > @@ -138,6 +143,44 @@ fail:
> > PUT_REMOTE_WAIT(wait);
> > }
> >
> > +static void process_device_add_msg(ProcMsg *msg)
> > +{
> > + Error *local_err = NULL;
> > + const char *json = (const char *)msg->data2;
> > + int wait = msg->fds[0];
> > + QObject *qobj = NULL;
> > + QDict *qdict = NULL;
> > + QemuOpts *opts = NULL;
> > +
> > + qobj = qobject_from_json(json, &local_err);
> > + if (local_err) {
> > + goto fail;
> > + }
> > +
> > + qdict = qobject_to(QDict, qobj);
> > + assert(qdict);
> > +
> > + opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict,
> > &local_err);
> > + if (local_err) {
> > + goto fail;
> > + }
> > +
> > + (void)qdev_device_add(opts, &local_err);
> > + if (local_err) {
> > + goto fail;
> > + }
> > +
> > +fail:
> > + if (local_err) {
> > + error_report_err(local_err);
> > + /* TODO: communicate the exact error message to proxy */
> > + }
> > +
> > + notify_proxy(wait, 1);
> > +
> > + PUT_REMOTE_WAIT(wait);
> > +}
> > +
> > static void process_msg(GIOCondition cond)
> > {
> > ProcMsg *msg = NULL;
> > @@ -189,6 +232,9 @@ static void process_msg(GIOCondition cond)
> > case SET_IRQFD:
> > process_set_irqfd_msg(remote_pci_dev, msg);
> > break;
> > + case DEVICE_ADD:
> > + process_device_add_msg(msg);
> > + break;
>
> wrong patch?
>
> > default:
> > error_setg(&err, "Unknown command");
> > goto finalize_loop;
> > @@ -225,6 +271,8 @@ int main(int argc, char *argv[])
> >
> > bdrv_init_with_whitelist();
> >
> > + qemu_add_opts(&qemu_device_opts);
> > +
>
> wrong patch?
> > if (qemu_init_main_loop(&err)) {
> > error_report_err(err);
> > return -EBUSY;
> > --
> > 1.8.3.1
> >
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK