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X-Received-From: 134.134.136.20 Subject: Re: [Qemu-devel] [PATCH v7 09/13] vfio: Add save state functions to SaveVMHandlers X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Yan Zhao Cc: "Zhengxiao.zx@Alibaba-inc.com" , "Tian, Kevin" , "Liu, Yi L" , "cjia@nvidia.com" , "eskultet@redhat.com" , "Yang, Ziye" , "qemu-devel@nongnu.org" , "cohuck@redhat.com" , "shuangtai.tst@alibaba-inc.com" , "dgilbert@redhat.com" , "Wang, Zhi A" , "mlevitsk@redhat.com" , "pasic@linux.ibm.com" , "aik@ozlabs.ru" , "alex.williamson@redhat.com" , "eauger@redhat.com" , "felipe@nutanix.com" , "jonathan.davies@nutanix.com" , "Liu, Changpeng" , "Ken.Xue@amd.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Jul 09, 2019 at 05:49:16PM +0800, Kirti Wankhede wrote: > Added .save_live_pending, .save_live_iterate and .save_live_complete_precopy > functions. These functions handles pre-copy and stop-and-copy phase. > > In _SAVING|_RUNNING device state or pre-copy phase: > - read pending_bytes > - read data_offset - indicates kernel driver to write data to staging > buffer which is mmapped. > - read data_size - amount of data in bytes written by vendor driver in migration > region. > - if data section is trapped, pread() from data_offset of data_size. > - if data section is mmaped, read mmaped buffer of data_size. > - Write data packet to file stream as below: > {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data, > VFIO_MIG_FLAG_END_OF_STATE } > > In _SAVING device state or stop-and-copy phase > a. read config space of device and save to migration file stream. This > doesn't need to be from vendor driver. Any other special config state > from driver can be saved as data in following iteration. > b. read pending_bytes > c. read data_offset - indicates kernel driver to write data to staging > buffer which is mmapped. > d. read data_size - amount of data in bytes written by vendor driver in > migration region. > e. if data section is trapped, pread() from data_offset of data_size. > f. if data section is mmaped, read mmaped buffer of data_size. > g. Write data packet as below: > {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data} > h. iterate through steps b to g while (pending_bytes > 0) > i. Write {VFIO_MIG_FLAG_END_OF_STATE} > > When data region is mapped, its user's responsibility to read data from > data_offset of data_size before moving to next steps. > > .save_live_iterate runs outside the iothread lock in the migration case, which > could race with asynchronous call to get dirty page list causing data corruption > in mapped migration region. Mutex added here to serial migration buffer read > operation. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > hw/vfio/migration.c | 246 +++++++++++++++++++++++++++++++++++++++++++++++++++ > hw/vfio/trace-events | 6 ++ > 2 files changed, 252 insertions(+) > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 0597a45fda2d..4e9b4cce230b 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -117,6 +117,138 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t state) > return 0; > } > > +static void *find_data_region(VFIORegion *region, > + uint64_t data_offset, > + uint64_t data_size) > +{ > + void *ptr = NULL; > + int i; > + > + for (i = 0; i < region->nr_mmaps; i++) { > + if ((data_offset >= region->mmaps[i].offset) && > + (data_offset < region->mmaps[i].offset + region->mmaps[i].size) && > + (data_size <= region->mmaps[i].size)) { > + ptr = region->mmaps[i].mmap + (data_offset - > + region->mmaps[i].offset); > + break; > + } > + } > + return ptr; > +} > + > +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev) > +{ > + VFIOMigration *migration = vbasedev->migration; > + VFIORegion *region = &migration->region.buffer; > + uint64_t data_offset = 0, data_size = 0; > + int ret; > + > + ret = pread(vbasedev->fd, &data_offset, sizeof(data_offset), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + data_offset)); > + if (ret != sizeof(data_offset)) { > + error_report("%s: Failed to get migration buffer data offset %d", > + vbasedev->name, ret); > + return -EINVAL; > + } > + > + ret = pread(vbasedev->fd, &data_size, sizeof(data_size), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + data_size)); > + if (ret != sizeof(data_size)) { > + error_report("%s: Failed to get migration buffer data size %d", > + vbasedev->name, ret); > + return -EINVAL; > + } > + > + if (data_size > 0) { > + void *buf = NULL; > + bool buffer_mmaped; > + > + if (region->mmaps) { > + buf = find_data_region(region, data_offset, data_size); > + } > + > + buffer_mmaped = (buf != NULL) ? true : false; > + > + if (!buffer_mmaped) { > + buf = g_try_malloc0(data_size); > + if (!buf) { > + error_report("%s: Error allocating buffer ", __func__); > + return -ENOMEM; > + } > + > + ret = pread(vbasedev->fd, buf, data_size, > + region->fd_offset + data_offset); > + if (ret != data_size) { > + error_report("%s: Failed to get migration data %d", > + vbasedev->name, ret); > + g_free(buf); > + return -EINVAL; > + } > + } > + > + qemu_put_be64(f, data_size); > + qemu_put_buffer(f, buf, data_size); > + > + if (!buffer_mmaped) { > + g_free(buf); > + } > + migration->pending_bytes -= data_size; This line "migration->pending_bytes -= data_size;" is not necessary, as it will be updated anyway in vfio_update_pending() > + } else { > + qemu_put_be64(f, data_size); > + } > + > + trace_vfio_save_buffer(vbasedev->name, data_offset, data_size, > + migration->pending_bytes); > + > + ret = qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + return data_size; > +} > + > +static int vfio_update_pending(VFIODevice *vbasedev) > +{ > + VFIOMigration *migration = vbasedev->migration; > + VFIORegion *region = &migration->region.buffer; > + uint64_t pending_bytes = 0; > + int ret; > + > + ret = pread(vbasedev->fd, &pending_bytes, sizeof(pending_bytes), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + pending_bytes)); > + if ((ret < 0) || (ret != sizeof(pending_bytes))) { > + error_report("%s: Failed to get pending bytes %d", > + vbasedev->name, ret); > + migration->pending_bytes = 0; > + return (ret < 0) ? ret : -EINVAL; > + } > + > + migration->pending_bytes = pending_bytes; > + trace_vfio_update_pending(vbasedev->name, pending_bytes); > + return 0; > +} > + > +static int vfio_save_device_config_state(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE); > + > + if (vbasedev->ops && vbasedev->ops->vfio_save_config) { > + vbasedev->ops->vfio_save_config(vbasedev, f); > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + trace_vfio_save_device_config_state(vbasedev->name); > + > + return qemu_file_get_error(f); > +} > + > /* ---------------------------------------------------------------------- */ > > static int vfio_save_setup(QEMUFile *f, void *opaque) > @@ -178,9 +310,123 @@ static void vfio_save_cleanup(void *opaque) > trace_vfio_save_cleanup(vbasedev->name); > } > > +static void vfio_save_pending(QEMUFile *f, void *opaque, > + uint64_t threshold_size, > + uint64_t *res_precopy_only, > + uint64_t *res_compatible, > + uint64_t *res_postcopy_only) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + int ret; > + > + ret = vfio_update_pending(vbasedev); > + if (ret) { > + return; > + } > + > + *res_precopy_only += migration->pending_bytes; > + > + trace_vfio_save_pending(vbasedev->name, *res_precopy_only, > + *res_postcopy_only, *res_compatible); > +} > + > +static int vfio_save_iterate(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + int ret, data_size; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); > + > + qemu_mutex_lock(&migration->lock); > + data_size = vfio_save_buffer(f, vbasedev); > + qemu_mutex_unlock(&migration->lock); > + > + if (data_size < 0) { > + error_report("%s: vfio_save_buffer failed %s", vbasedev->name, > + strerror(errno)); > + return data_size; > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + ret = qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + trace_vfio_save_iterate(vbasedev->name, data_size); > + if (data_size == 0) { > + /* indicates data finished, goto complete phase */ > + return 1; > + } > + > + return 0; > +} > + > +static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + int ret; > + > + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_SAVING); > + if (ret) { > + error_report("%s: Failed to set state STOP and SAVING", > + vbasedev->name); > + return ret; > + } > + > + ret = vfio_save_device_config_state(f, opaque); > + if (ret) { > + return ret; > + } > + > + ret = vfio_update_pending(vbasedev); > + if (ret) { > + return ret; > + } > + > + while (migration->pending_bytes > 0) { > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); > + ret = vfio_save_buffer(f, vbasedev); > + if (ret < 0) { > + error_report("%s: Failed to save buffer", vbasedev->name); > + return ret; > + } else if (ret == 0) { > + break; > + } > + > + ret = vfio_update_pending(vbasedev); > + if (ret) { > + return ret; > + } > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + ret = qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_MASK); > + if (ret) { > + error_report("%s: Failed to set state STOPPED", vbasedev->name); > + return ret; > + } > + > + trace_vfio_save_complete_precopy(vbasedev->name); > + return ret; > +} > + > static SaveVMHandlers savevm_vfio_handlers = { > .save_setup = vfio_save_setup, > .save_cleanup = vfio_save_cleanup, > + .save_live_pending = vfio_save_pending, > + .save_live_iterate = vfio_save_iterate, > + .save_live_complete_precopy = vfio_save_complete_precopy, > }; > > /* ---------------------------------------------------------------------- */ > diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events > index 4bb43f18f315..bdf40ba368c7 100644 > --- a/hw/vfio/trace-events > +++ b/hw/vfio/trace-events > @@ -151,3 +151,9 @@ vfio_vmstate_change(char *name, int running, const char *reason, uint32_t dev_st > vfio_migration_state_notifier(char *name, int state) " (%s) state %d" > vfio_save_setup(char *name) " (%s)" > vfio_save_cleanup(char *name) " (%s)" > +vfio_save_buffer(char *name, uint64_t data_offset, uint64_t data_size, uint64_t pending) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64" pending 0x%"PRIx64 > +vfio_update_pending(char *name, uint64_t pending) " (%s) pending 0x%"PRIx64 > +vfio_save_device_config_state(char *name) " (%s)" > +vfio_save_pending(char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64 > +vfio_save_iterate(char *name, int data_size) " (%s) data_size %d" > +vfio_save_complete_precopy(char *name) " (%s)" > -- > 2.7.0 >