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Thu, 21 May 2020 15:37:43 +0000 (UTC) Date: Thu, 21 May 2020 16:37:40 +0100 From: "Dr. David Alan Gilbert" To: Kirti Wankhede Subject: Re: [PATCH QEMU v23 09/18] vfio: Add save state functions to SaveVMHandlers Message-ID: <20200521153740.GH2752@work-vm> References: <1589999088-31477-1-git-send-email-kwankhede@nvidia.com> <1589999088-31477-10-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 In-Reply-To: <1589999088-31477-10-git-send-email-kwankhede@nvidia.com> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=205.139.110.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/21 06:06:22 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, T_HK_NAME_DR=0.01, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: , Cc: cohuck@redhat.com, cjia@nvidia.com, aik@ozlabs.ru, Zhengxiao.zx@alibaba-inc.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, peterx@redhat.com, eauger@redhat.com, yi.l.liu@intel.com, quintela@redhat.com, ziye.yang@intel.com, armbru@redhat.com, mlevitsk@redhat.com, pasic@linux.ibm.com, felipe@nutanix.com, zhi.a.wang@intel.com, kevin.tian@intel.com, yan.y.zhao@intel.com, alex.williamson@redhat.com, changpeng.liu@intel.com, eskultet@redhat.com, Ken.Xue@amd.com, jonathan.davies@nutanix.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Kirti Wankhede (kwankhede@nvidia.com) 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. If pending_bytes > 0, go through below steps. > - read data_offset - indicates kernel driver to write data to staging > buffer. > - read data_size - amount of data in bytes written by vendor driver in > migration region. > - read data_size bytes of data from data_offset in the migration region. > - 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. If pending_bytes > 0, go through below steps. > c. read data_offset - indicates kernel driver to write data to staging > buffer. > d. read data_size - amount of data in bytes written by vendor driver in > migration region. > e. read data_size bytes of data from data_offset in the migration region. > f. Write data packet as below: > {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data} > g. iterate through steps b to f while (pending_bytes > 0) > h. 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. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > hw/vfio/migration.c | 254 +++++++++++++++++++++++++++++++++++++++++- > hw/vfio/trace-events | 6 + > include/hw/vfio/vfio-common.h | 1 + > 3 files changed, 260 insertions(+), 1 deletion(-) > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 773c8d16b1c1..d90bd2296afd 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -139,6 +139,137 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, > 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) && that checks the bit we want to map starts at or after this region > + (data_offset < region->mmaps[i].offset + region->mmaps[i].size) && and the bit we want to map starts before the end of this region > + (data_size <= region->mmaps[i].size)) { Shouldn't that check take into account the offset? If data_offset-mmaps[i].offset is almost mmaps[i].size then we would be accessing data_size after the end of the region? > + ptr = region->mmaps[i].mmap + (data_offset - > + region->mmaps[i].offset); > + break; > + } > + } > + return ptr; > +} > + > +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev) ^^^ do you need to make this int64_t or ssize_t - internally to this function it's uint64_t but you're also returning errors. (and then fix up the trace_ and callers below) > +{ > + VFIOMigration *migration = vbasedev->migration; > + VFIORegion *region = &migration->region; > + 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); > + > + if (!buffer_mmaped) { > + buf = g_try_malloc(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); > + } > + } 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; > + 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))) { You read values from the vfio buffer in a few places and don't check the sizeof() in ret; this either needs wrapping in a function/macro/something or doing consistently. > + 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) > @@ -157,7 +288,7 @@ static int vfio_save_setup(QEMUFile *f, void *opaque) > qemu_mutex_unlock_iothread(); > if (ret) { > error_report("%s: Failed to mmap VFIO migration region %d: %s", > - vbasedev->name, migration->region.index, > + vbasedev->name, migration->region.nr, > strerror(-ret)); > return ret; > } > @@ -190,9 +321,130 @@ 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); > + > + if (migration->pending_bytes == 0) { > + ret = vfio_update_pending(vbasedev); > + if (ret) { > + return ret; > + } > + > + if (migration->pending_bytes == 0) { > + /* indicates data finished, goto complete phase */ Is that right that you've sent a DEV_DATA_STATE but not an END_OF_STATE? > + return 1; > + } > + } > + > + data_size = vfio_save_buffer(f, vbasedev); > + > + 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); > + > + 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_RUNNING, > + 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_SAVING, 0); > + 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 86c18def016e..9a1c5e17d97f 100644 > --- a/hw/vfio/trace-events > +++ b/hw/vfio/trace-events > @@ -151,3 +151,9 @@ vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t > 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)" > +vfio_save_buffer(const 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(const char *name, uint64_t pending) " (%s) pending 0x%"PRIx64 > +vfio_save_device_config_state(const char *name) " (%s)" > +vfio_save_pending(const char *name, uint64_t precopy, uint64_t postcopy, uint64_t compatible) " (%s) precopy 0x%"PRIx64" postcopy 0x%"PRIx64" compatible 0x%"PRIx64 > +vfio_save_iterate(const char *name, int data_size) " (%s) data_size %d" > +vfio_save_complete_precopy(const char *name) " (%s)" > diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h > index 28f55f66d019..c78033e4149d 100644 > --- a/include/hw/vfio/vfio-common.h > +++ b/include/hw/vfio/vfio-common.h > @@ -60,6 +60,7 @@ typedef struct VFIORegion { > > typedef struct VFIOMigration { > VFIORegion region; > + uint64_t pending_bytes; > } VFIOMigration; > > typedef struct VFIOAddressSpace { > -- > 2.7.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK