| Message ID | 1603365127-14202-8-git-send-email-kwankhede@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add migration support for VFIO devices | expand |
On Thu, 22 Oct 2020 16:41:57 +0530 Kirti Wankhede <kwankhede@nvidia.com> wrote: > Define flags to be used as delimiter in migration stream for VFIO devices. > Added .save_setup and .save_cleanup functions. Map & unmap migration > region from these functions at source during saving or pre-copy phase. > > Set VFIO device state depending on VM's state. During live migration, VM is > running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO > device. During save-restore, VM is paused, _SAVING state is set for VFIO device. > > Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> > Reviewed-by: Neo Jia <cjia@nvidia.com> > --- > hw/vfio/migration.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > hw/vfio/trace-events | 2 ++ > 2 files changed, 98 insertions(+) > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 7c4fa0d08ea6..2e1054bf7f43 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -8,12 +8,15 @@ > */ > > #include "qemu/osdep.h" > +#include "qemu/main-loop.h" > +#include "qemu/cutils.h" > #include <linux/vfio.h> > > #include "sysemu/runstate.h" > #include "hw/vfio/vfio-common.h" > #include "cpu.h" > #include "migration/migration.h" > +#include "migration/vmstate.h" > #include "migration/qemu-file.h" > #include "migration/register.h" > #include "migration/blocker.h" > @@ -25,6 +28,22 @@ > #include "trace.h" > #include "hw/hw.h" > > +/* > + * Flags to be used as unique delimiters for VFIO devices in the migration > + * stream. These flags are composed as: > + * 0xffffffff => MSB 32-bit all 1s > + * 0xef10 => Magic ID, represents emulated (virtual) function IO > + * 0x0000 => 16-bits reserved for flags > + * > + * The beginning of state information is marked by _DEV_CONFIG_STATE, > + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a > + * certain state information is marked by _END_OF_STATE. > + */ > +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) > +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) > +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) > +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) > + > static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count, > off_t off, bool iswrite) > { > @@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, > return 0; > } > > +/* ---------------------------------------------------------------------- */ > + > +static int vfio_save_setup(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + int ret; > + > + trace_vfio_save_setup(vbasedev->name); > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); > + > + if (migration->region.mmaps) { > + /* > + * vfio_region_mmap() called from migration thread. Memory API called > + * from vfio_regio_mmap() need it when called from outdide the main loop > + * thread. > + */ Thanks for adding this detail, maybe refine slightly as: Calling vfio_region_mmap() from migration thread. Memory APIs called from this function require locking the iothread when called from outside the main loop thread. Does that capture the intent? > + qemu_mutex_lock_iothread(); > + ret = vfio_region_mmap(&migration->region); > + qemu_mutex_unlock_iothread(); > + if (ret) { > + error_report("%s: Failed to mmap VFIO migration region: %s", > + vbasedev->name, strerror(-ret)); > + error_report("%s: Falling back to slow path", vbasedev->name); > + } > + } > + > + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK, > + VFIO_DEVICE_STATE_SAVING); > + if (ret) { > + error_report("%s: Failed to set state SAVING", vbasedev->name); > + return ret; > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + ret = qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + return 0; > +} > + > +static void vfio_save_cleanup(void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + > + if (migration->region.mmaps) { > + vfio_region_unmap(&migration->region); > + } Are we in a different thread context here that we don't need that same iothread locking? > + trace_vfio_save_cleanup(vbasedev->name); > +} > + > +static SaveVMHandlers savevm_vfio_handlers = { > + .save_setup = vfio_save_setup, > + .save_cleanup = vfio_save_cleanup, > +}; > + > +/* ---------------------------------------------------------------------- */ > + > static void vfio_vmstate_change(void *opaque, int running, RunState state) > { > VFIODevice *vbasedev = opaque; > @@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev, > int ret; > Object *obj; > VFIOMigration *migration; > + char id[256] = ""; > + g_autofree char *path = NULL, *oid; AIUI, oid must also be initialized as a g_autofree variable. > > if (!vbasedev->ops->vfio_get_object) { > return -EINVAL; > @@ -248,6 +332,18 @@ static int vfio_migration_init(VFIODevice *vbasedev, > > vbasedev->migration = migration; > migration->vbasedev = vbasedev; > + > + oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj))); > + if (oid) { > + path = g_strdup_printf("%s/vfio", oid); > + } else { > + path = g_strdup("vfio"); If we get here then all vfio devices have the same id string. Isn't that a problem? Thanks, Alex > + } > + strpadcpy(id, sizeof(id), path, '\0'); > + > + register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers, > + vbasedev); > + > migration->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change, > vbasedev); > migration->migration_state.notify = vfio_migration_state_notifier; > diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events > index 78d7d83b5ef8..f148b5e828c1 100644 > --- a/hw/vfio/trace-events > +++ b/hw/vfio/trace-events > @@ -151,3 +151,5 @@ vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d" > vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d" > vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d" > vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s" > +vfio_save_setup(const char *name) " (%s)" > +vfio_save_cleanup(const char *name) " (%s)"
On 10/23/2020 12:21 AM, Alex Williamson wrote: > On Thu, 22 Oct 2020 16:41:57 +0530 > Kirti Wankhede <kwankhede@nvidia.com> wrote: > >> Define flags to be used as delimiter in migration stream for VFIO devices. >> Added .save_setup and .save_cleanup functions. Map & unmap migration >> region from these functions at source during saving or pre-copy phase. >> >> Set VFIO device state depending on VM's state. During live migration, VM is >> running when .save_setup is called, _SAVING | _RUNNING state is set for VFIO >> device. During save-restore, VM is paused, _SAVING state is set for VFIO device. >> >> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> >> Reviewed-by: Neo Jia <cjia@nvidia.com> >> --- >> hw/vfio/migration.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> hw/vfio/trace-events | 2 ++ >> 2 files changed, 98 insertions(+) >> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c >> index 7c4fa0d08ea6..2e1054bf7f43 100644 >> --- a/hw/vfio/migration.c >> +++ b/hw/vfio/migration.c >> @@ -8,12 +8,15 @@ >> */ >> >> #include "qemu/osdep.h" >> +#include "qemu/main-loop.h" >> +#include "qemu/cutils.h" >> #include <linux/vfio.h> >> >> #include "sysemu/runstate.h" >> #include "hw/vfio/vfio-common.h" >> #include "cpu.h" >> #include "migration/migration.h" >> +#include "migration/vmstate.h" >> #include "migration/qemu-file.h" >> #include "migration/register.h" >> #include "migration/blocker.h" >> @@ -25,6 +28,22 @@ >> #include "trace.h" >> #include "hw/hw.h" >> >> +/* >> + * Flags to be used as unique delimiters for VFIO devices in the migration >> + * stream. These flags are composed as: >> + * 0xffffffff => MSB 32-bit all 1s >> + * 0xef10 => Magic ID, represents emulated (virtual) function IO >> + * 0x0000 => 16-bits reserved for flags >> + * >> + * The beginning of state information is marked by _DEV_CONFIG_STATE, >> + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a >> + * certain state information is marked by _END_OF_STATE. >> + */ >> +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) >> +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) >> +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) >> +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) >> + >> static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count, >> off_t off, bool iswrite) >> { >> @@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, >> return 0; >> } >> >> +/* ---------------------------------------------------------------------- */ >> + >> +static int vfio_save_setup(QEMUFile *f, void *opaque) >> +{ >> + VFIODevice *vbasedev = opaque; >> + VFIOMigration *migration = vbasedev->migration; >> + int ret; >> + >> + trace_vfio_save_setup(vbasedev->name); >> + >> + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); >> + >> + if (migration->region.mmaps) { >> + /* >> + * vfio_region_mmap() called from migration thread. Memory API called >> + * from vfio_regio_mmap() need it when called from outdide the main loop >> + * thread. >> + */ > > Thanks for adding this detail, maybe refine slightly as: > > Calling vfio_region_mmap() from migration thread. Memory APIs called > from this function require locking the iothread when called from > outside the main loop thread. > > Does that capture the intent? > Ok. >> + qemu_mutex_lock_iothread(); >> + ret = vfio_region_mmap(&migration->region); >> + qemu_mutex_unlock_iothread(); >> + if (ret) { >> + error_report("%s: Failed to mmap VFIO migration region: %s", >> + vbasedev->name, strerror(-ret)); >> + error_report("%s: Falling back to slow path", vbasedev->name); >> + } >> + } >> + >> + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK, >> + VFIO_DEVICE_STATE_SAVING); >> + if (ret) { >> + error_report("%s: Failed to set state SAVING", vbasedev->name); >> + return ret; >> + } >> + >> + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); >> + >> + ret = qemu_file_get_error(f); >> + if (ret) { >> + return ret; >> + } >> + >> + return 0; >> +} >> + >> +static void vfio_save_cleanup(void *opaque) >> +{ >> + VFIODevice *vbasedev = opaque; >> + VFIOMigration *migration = vbasedev->migration; >> + >> + if (migration->region.mmaps) { >> + vfio_region_unmap(&migration->region); >> + } > > > Are we in a different thread context here that we don't need that same > iothread locking? > qemu_savevm_state_setup() is called without holding iothread lock and qemu_savevm_state_cleanup() is called holding iothread lock, so we don't need lock here. > >> + trace_vfio_save_cleanup(vbasedev->name); >> +} >> + >> +static SaveVMHandlers savevm_vfio_handlers = { >> + .save_setup = vfio_save_setup, >> + .save_cleanup = vfio_save_cleanup, >> +}; >> + >> +/* ---------------------------------------------------------------------- */ >> + >> static void vfio_vmstate_change(void *opaque, int running, RunState state) >> { >> VFIODevice *vbasedev = opaque; >> @@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev, >> int ret; >> Object *obj; >> VFIOMigration *migration; >> + char id[256] = ""; >> + g_autofree char *path = NULL, *oid; > > > AIUI, oid must also be initialized as a g_autofree variable. > >> >> if (!vbasedev->ops->vfio_get_object) { >> return -EINVAL; >> @@ -248,6 +332,18 @@ static int vfio_migration_init(VFIODevice *vbasedev, >> >> vbasedev->migration = migration; >> migration->vbasedev = vbasedev; >> + >> + oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj))); >> + if (oid) { >> + path = g_strdup_printf("%s/vfio", oid); >> + } else { >> + path = g_strdup("vfio"); > > > If we get here then all vfio devices have the same id string. Isn't > that a problem? Thanks, > Most of the bus types has get_dev_path() callback implemented which is called from get_id, so there are very less chance to get here. With above change, id string we get looks like '0000:00:04.0/vfio', trace logs below: qemu_loadvm_state_section_startfull 61.942 pid=625231 section_id=0x2f idstr=b'0000:00:04.0/vfio' instance_id=0x0 version_id=0x1 qemu_loadvm_state_section_startfull 1.242 pid=625231 section_id=0x30 idstr=b'0000:00:05.0/vfio' instance_id=0x0 version_id=0x1 where '0000:00:04.0'shows location within guest, so that it gets preserved and used during resume. In the worst when it is not present, idstr remains same but instance_id changes: qemu_loadvm_state_section_startfull 54.931 pid=609474 section_id=0x2f idstr=b'vfio' instance_id=0x0 version_id=0x1 qemu_loadvm_state_section_startfull 1.180 pid=609474 section_id=0x30 idstr=b'vfio' instance_id=0x1 version_id=0x1 But there is no other way to know location of the device within guest. Dave, any suggestions here? Thanks, Kirti > Alex > > >> + } >> + strpadcpy(id, sizeof(id), path, '\0'); >> + >> + register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers, >> + vbasedev); >> + >> migration->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change, >> vbasedev); >> migration->migration_state.notify = vfio_migration_state_notifier; >> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events >> index 78d7d83b5ef8..f148b5e828c1 100644 >> --- a/hw/vfio/trace-events >> +++ b/hw/vfio/trace-events >> @@ -151,3 +151,5 @@ vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d" >> vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d" >> vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d" >> vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s" >> +vfio_save_setup(const char *name) " (%s)" >> +vfio_save_cleanup(const char *name) " (%s)" > >
diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 7c4fa0d08ea6..2e1054bf7f43 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -8,12 +8,15 @@ */ #include "qemu/osdep.h" +#include "qemu/main-loop.h" +#include "qemu/cutils.h" #include <linux/vfio.h> #include "sysemu/runstate.h" #include "hw/vfio/vfio-common.h" #include "cpu.h" #include "migration/migration.h" +#include "migration/vmstate.h" #include "migration/qemu-file.h" #include "migration/register.h" #include "migration/blocker.h" @@ -25,6 +28,22 @@ #include "trace.h" #include "hw/hw.h" +/* + * Flags to be used as unique delimiters for VFIO devices in the migration + * stream. These flags are composed as: + * 0xffffffff => MSB 32-bit all 1s + * 0xef10 => Magic ID, represents emulated (virtual) function IO + * 0x0000 => 16-bits reserved for flags + * + * The beginning of state information is marked by _DEV_CONFIG_STATE, + * _DEV_SETUP_STATE, or _DEV_DATA_STATE, respectively. The end of a + * certain state information is marked by _END_OF_STATE. + */ +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) + static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count, off_t off, bool iswrite) { @@ -129,6 +148,69 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, return 0; } +/* ---------------------------------------------------------------------- */ + +static int vfio_save_setup(QEMUFile *f, void *opaque) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + int ret; + + trace_vfio_save_setup(vbasedev->name); + + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); + + if (migration->region.mmaps) { + /* + * vfio_region_mmap() called from migration thread. Memory API called + * from vfio_regio_mmap() need it when called from outdide the main loop + * thread. + */ + qemu_mutex_lock_iothread(); + ret = vfio_region_mmap(&migration->region); + qemu_mutex_unlock_iothread(); + if (ret) { + error_report("%s: Failed to mmap VFIO migration region: %s", + vbasedev->name, strerror(-ret)); + error_report("%s: Falling back to slow path", vbasedev->name); + } + } + + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK, + VFIO_DEVICE_STATE_SAVING); + if (ret) { + error_report("%s: Failed to set state SAVING", vbasedev->name); + return ret; + } + + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); + + ret = qemu_file_get_error(f); + if (ret) { + return ret; + } + + return 0; +} + +static void vfio_save_cleanup(void *opaque) +{ + VFIODevice *vbasedev = opaque; + VFIOMigration *migration = vbasedev->migration; + + if (migration->region.mmaps) { + vfio_region_unmap(&migration->region); + } + trace_vfio_save_cleanup(vbasedev->name); +} + +static SaveVMHandlers savevm_vfio_handlers = { + .save_setup = vfio_save_setup, + .save_cleanup = vfio_save_cleanup, +}; + +/* ---------------------------------------------------------------------- */ + static void vfio_vmstate_change(void *opaque, int running, RunState state) { VFIODevice *vbasedev = opaque; @@ -219,6 +301,8 @@ static int vfio_migration_init(VFIODevice *vbasedev, int ret; Object *obj; VFIOMigration *migration; + char id[256] = ""; + g_autofree char *path = NULL, *oid; if (!vbasedev->ops->vfio_get_object) { return -EINVAL; @@ -248,6 +332,18 @@ static int vfio_migration_init(VFIODevice *vbasedev, vbasedev->migration = migration; migration->vbasedev = vbasedev; + + oid = vmstate_if_get_id(VMSTATE_IF(DEVICE(obj))); + if (oid) { + path = g_strdup_printf("%s/vfio", oid); + } else { + path = g_strdup("vfio"); + } + strpadcpy(id, sizeof(id), path, '\0'); + + register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers, + vbasedev); + migration->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change, vbasedev); migration->migration_state.notify = vfio_migration_state_notifier; diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events index 78d7d83b5ef8..f148b5e828c1 100644 --- a/hw/vfio/trace-events +++ b/hw/vfio/trace-events @@ -151,3 +151,5 @@ vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d" vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d" vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d" vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s" +vfio_save_setup(const char *name) " (%s)" +vfio_save_cleanup(const char *name) " (%s)"