| Message ID | 20230102010821.5462-1-j@getutm.app |
|---|---|
| State | New |
| Headers | show |
| Series | vmnet: stop recieving events when VM is stopped | expand |
On Mon, Jan 2, 2023 at 9:08 AM Joelle van Dyne <j@getutm.app> wrote: > > When the VM is stopped using the HMP command "stop", soon the handler will > stop reading from the vmnet interface. This causes a flood of > `VMNET_INTERFACE_PACKETS_AVAILABLE` events to arrive and puts the host CPU > at 100%. We fix this by removing the event handler from vmnet when the VM > is no longer in a running state and restore it when we return to a running > state. > > Signed-off-by: Joelle van Dyne <j@getutm.app> Applied. Thanks > --- > net/vmnet_int.h | 2 ++ > net/vmnet-common.m | 48 +++++++++++++++++++++++++++++++++------------- > 2 files changed, 37 insertions(+), 13 deletions(-) > > diff --git a/net/vmnet_int.h b/net/vmnet_int.h > index adf6e8c20d..ffba92108f 100644 > --- a/net/vmnet_int.h > +++ b/net/vmnet_int.h > @@ -46,6 +46,8 @@ typedef struct VmnetState { > int packets_send_end_pos; > > struct iovec iov_buf[VMNET_PACKETS_LIMIT]; > + > + VMChangeStateEntry *change; > } VmnetState; > > const char *vmnet_status_map_str(vmnet_return_t status); > diff --git a/net/vmnet-common.m b/net/vmnet-common.m > index 2cb60b9ddd..2958283485 100644 > --- a/net/vmnet-common.m > +++ b/net/vmnet-common.m > @@ -17,6 +17,7 @@ > #include "clients.h" > #include "qemu/error-report.h" > #include "qapi/error.h" > +#include "sysemu/runstate.h" > > #include <vmnet/vmnet.h> > #include <dispatch/dispatch.h> > @@ -242,6 +243,35 @@ static void vmnet_bufs_init(VmnetState *s) > } > } > > +/** > + * Called on state change to un-register/re-register handlers > + */ > +static void vmnet_vm_state_change_cb(void *opaque, bool running, RunState state) > +{ > + VmnetState *s = opaque; > + > + if (running) { > + vmnet_interface_set_event_callback( > + s->vmnet_if, > + VMNET_INTERFACE_PACKETS_AVAILABLE, > + s->if_queue, > + ^(interface_event_t event_id, xpc_object_t event) { > + assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE); > + /* > + * This function is being called from a non qemu thread, so > + * we only schedule a BH, and do the rest of the io completion > + * handling from vmnet_send_bh() which runs in a qemu context. > + */ > + qemu_bh_schedule(s->send_bh); > + }); > + } else { > + vmnet_interface_set_event_callback( > + s->vmnet_if, > + VMNET_INTERFACE_PACKETS_AVAILABLE, > + NULL, > + NULL); > + } > +} > > int vmnet_if_create(NetClientState *nc, > xpc_object_t if_desc, > @@ -329,19 +359,9 @@ int vmnet_if_create(NetClientState *nc, > s->packets_send_current_pos = 0; > s->packets_send_end_pos = 0; > > - vmnet_interface_set_event_callback( > - s->vmnet_if, > - VMNET_INTERFACE_PACKETS_AVAILABLE, > - s->if_queue, > - ^(interface_event_t event_id, xpc_object_t event) { > - assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE); > - /* > - * This function is being called from a non qemu thread, so > - * we only schedule a BH, and do the rest of the io completion > - * handling from vmnet_send_bh() which runs in a qemu context. > - */ > - qemu_bh_schedule(s->send_bh); > - }); > + vmnet_vm_state_change_cb(s, 1, RUN_STATE_RUNNING); > + > + s->change = qemu_add_vm_change_state_handler(vmnet_vm_state_change_cb, s); > > return 0; > } > @@ -356,6 +376,8 @@ void vmnet_cleanup_common(NetClientState *nc) > return; > } > > + vmnet_vm_state_change_cb(s, 0, RUN_STATE_SHUTDOWN); > + qemu_del_vm_change_state_handler(s->change); > if_stopped_sem = dispatch_semaphore_create(0); > vmnet_stop_interface( > s->vmnet_if, > -- > 2.28.0 >
diff --git a/net/vmnet_int.h b/net/vmnet_int.h index adf6e8c20d..ffba92108f 100644 --- a/net/vmnet_int.h +++ b/net/vmnet_int.h @@ -46,6 +46,8 @@ typedef struct VmnetState { int packets_send_end_pos; struct iovec iov_buf[VMNET_PACKETS_LIMIT]; + + VMChangeStateEntry *change; } VmnetState; const char *vmnet_status_map_str(vmnet_return_t status); diff --git a/net/vmnet-common.m b/net/vmnet-common.m index 2cb60b9ddd..2958283485 100644 --- a/net/vmnet-common.m +++ b/net/vmnet-common.m @@ -17,6 +17,7 @@ #include "clients.h" #include "qemu/error-report.h" #include "qapi/error.h" +#include "sysemu/runstate.h" #include <vmnet/vmnet.h> #include <dispatch/dispatch.h> @@ -242,6 +243,35 @@ static void vmnet_bufs_init(VmnetState *s) } } +/** + * Called on state change to un-register/re-register handlers + */ +static void vmnet_vm_state_change_cb(void *opaque, bool running, RunState state) +{ + VmnetState *s = opaque; + + if (running) { + vmnet_interface_set_event_callback( + s->vmnet_if, + VMNET_INTERFACE_PACKETS_AVAILABLE, + s->if_queue, + ^(interface_event_t event_id, xpc_object_t event) { + assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE); + /* + * This function is being called from a non qemu thread, so + * we only schedule a BH, and do the rest of the io completion + * handling from vmnet_send_bh() which runs in a qemu context. + */ + qemu_bh_schedule(s->send_bh); + }); + } else { + vmnet_interface_set_event_callback( + s->vmnet_if, + VMNET_INTERFACE_PACKETS_AVAILABLE, + NULL, + NULL); + } +} int vmnet_if_create(NetClientState *nc, xpc_object_t if_desc, @@ -329,19 +359,9 @@ int vmnet_if_create(NetClientState *nc, s->packets_send_current_pos = 0; s->packets_send_end_pos = 0; - vmnet_interface_set_event_callback( - s->vmnet_if, - VMNET_INTERFACE_PACKETS_AVAILABLE, - s->if_queue, - ^(interface_event_t event_id, xpc_object_t event) { - assert(event_id == VMNET_INTERFACE_PACKETS_AVAILABLE); - /* - * This function is being called from a non qemu thread, so - * we only schedule a BH, and do the rest of the io completion - * handling from vmnet_send_bh() which runs in a qemu context. - */ - qemu_bh_schedule(s->send_bh); - }); + vmnet_vm_state_change_cb(s, 1, RUN_STATE_RUNNING); + + s->change = qemu_add_vm_change_state_handler(vmnet_vm_state_change_cb, s); return 0; } @@ -356,6 +376,8 @@ void vmnet_cleanup_common(NetClientState *nc) return; } + vmnet_vm_state_change_cb(s, 0, RUN_STATE_SHUTDOWN); + qemu_del_vm_change_state_handler(s->change); if_stopped_sem = dispatch_semaphore_create(0); vmnet_stop_interface( s->vmnet_if,
When the VM is stopped using the HMP command "stop", soon the handler will stop reading from the vmnet interface. This causes a flood of `VMNET_INTERFACE_PACKETS_AVAILABLE` events to arrive and puts the host CPU at 100%. We fix this by removing the event handler from vmnet when the VM is no longer in a running state and restore it when we return to a running state. Signed-off-by: Joelle van Dyne <j@getutm.app> --- net/vmnet_int.h | 2 ++ net/vmnet-common.m | 48 +++++++++++++++++++++++++++++++++------------- 2 files changed, 37 insertions(+), 13 deletions(-)