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Wed, 21 Oct 2020 14:30:52 +0000 Subject: Re: [PATCH v26 08/17] vfio: Add save state functions to SaveVMHandlers To: "Wang, Zhi A" , "alex.williamson@redhat.com" , "cjia@nvidia.com" References: <1600817059-26721-1-git-send-email-kwankhede@nvidia.com> <1600817059-26721-9-git-send-email-kwankhede@nvidia.com> X-Nvconfidentiality: public From: Kirti Wankhede Message-ID: <82b99c1c-9079-fcee-5ccf-011a3bb7fad7@nvidia.com> Date: Wed, 21 Oct 2020 20:00:48 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1603290576; bh=tiu92XyCugX1ugSyPsr9Sen7128Fx7wuIyio559JpPo=; h=Subject:To:CC:References:X-Nvconfidentiality:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=FZa4+UqC3wRZ7ww6ZnvpqGdaWjTMK4Enk7TotLNOrukOncNT7YCNf/t+f35rakp7X wfifNHYZmexPLA0clcgYnX8Vt0QwItT+FTLSedxFzTzfFXDPuSCHst/8e/TWnql+lC oWwHA9vfSUK1eAdB7oHl8WJZtUDVLGNCjpjA+njqWt8G64a1pEilwfXVCTL1vJ3BbN RZf5oCcaZKfUt97NQyP+76qhzsQH5MPFpoL8itWjmvrPhijJ8v7Qee6JX18kXrHgf1 ncdQUstQh+JxCss4OnVIS/0MWqCGefAyWVxGCmUb2eUHiIiplL/pfO2KOmz1RvXopP Qx/LHWvvysUQw== Received-SPF: pass client-ip=216.228.121.143; envelope-from=kwankhede@nvidia.com; helo=hqnvemgate24.nvidia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/21 10:31:10 X-ACL-Warn: Detected OS = Windows 7 or 8 [fuzzy] X-Spam_score_int: -70 X-Spam_score: -7.1 X-Spam_bar: ------- X-Spam_report: (-7.1 / 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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" , "aik@ozlabs.ru" , "Zhengxiao.zx@Alibaba-inc.com" , "shuangtai.tst@alibaba-inc.com" , "qemu-devel@nongnu.org" , "peterx@redhat.com" , "eauger@redhat.com" , "Liu, Yi L" , "quintela@redhat.com" , "Yang, Ziye" , "armbru@redhat.com" , "mlevitsk@redhat.com" , "pasic@linux.ibm.com" , "felipe@nutanix.com" , "Ken.Xue@amd.com" , "Tian, Kevin" , "Zhao, Yan Y" , "dgilbert@redhat.com" , "Liu, Changpeng" , "eskultet@redhat.com" , "jonathan.davies@nutanix.com" , "pbonzini@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/23/2020 5:12 PM, Wang, Zhi A wrote: > I met a problem when trying this patch. Mostly the problem happens if a device doesn't set any pending bytes in the iteration stage, which shows this device doesn't have a stage of iteration. I tried to reproduce this issue at my end and I didn't hit this case even if I do multiple iteration in pre-copy phase in live migration. In pre-copy phase, vendor driver receives read(pending_bytes) call back from .save_live_pending. If vendor driver don't have any data to send then return 0 as pending bytes. But I could reproduce this issue with savevm/VM snapshot from qemu-monitor. Agree with your fix, pulling in my next iteration. The QEMU in the destination machine will complain out-of-memory. After some investigation, it seems the vendor-specific bit stream is not complete and the QEMU in the destination machine will wrongly take a signature as the size of the section and failed to allocate the memory. Not sure if others meet the same problem. > > I solved this problem by the following fix and the qemu version I am using is v5.0.0.0. > Only this didn't fix the problem for me, have to reset pending_bytes from vfio_save_iterate() as .save_live_pending is not called during savevm/snapshot. Thanks for testing. Kirti > commit 13a80adc2cdddd48d76acf6a5dd715bcbf42b577 > Author: Zhi Wang > Date: Tue Sep 15 15:58:45 2020 +0300 > > fix > > Signed-off-by: Zhi Wang > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 09eec9c..e741319 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -453,10 +458,12 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque) > return ret; > } > > - if (migration->pending_bytes == 0) { > - /* indicates data finished, goto complete phase */ > - return 1; > - } > + if (migration->pending_bytes == 0) { > + /* indicates data finished, goto complete phase */ > + qemu_put_be64(f, 0); > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + return 1; > + } > } > > data_size = vfio_save_buffer(f, vbasedev); > > -----Original Message----- > From: Kirti Wankhede > Sent: Wednesday, September 23, 2020 2:24 AM > To: alex.williamson@redhat.com; cjia@nvidia.com > Cc: Tian, Kevin ; Yang, Ziye ; Liu, Changpeng ; Liu, Yi L ; mlevitsk@redhat.com; eskultet@redhat.com; cohuck@redhat.com; dgilbert@redhat.com; jonathan.davies@nutanix.com; eauger@redhat.com; aik@ozlabs.ru; pasic@linux.ibm.com; felipe@nutanix.com; Zhengxiao.zx@Alibaba-inc.com; shuangtai.tst@alibaba-inc.com; Ken.Xue@amd.com; Wang, Zhi A ; Zhao, Yan Y ; pbonzini@redhat.com; quintela@redhat.com; eblake@redhat.com; armbru@redhat.com; peterx@redhat.com; qemu-devel@nongnu.org; Kirti Wankhede > Subject: [PATCH v26 08/17] vfio: Add save state functions to SaveVMHandlers > > 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 | 273 ++++++++++++++++++++++++++++++++++++++++++ > hw/vfio/trace-events | 6 + > include/hw/vfio/vfio-common.h | 1 + > 3 files changed, 280 insertions(+) > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 8e8adaa25779..4611bb972228 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -180,6 +180,154 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, > return 0; > } > > +static void *get_data_section_size(VFIORegion *region, uint64_t data_offset, > + uint64_t data_size, uint64_t *size) > +{ > + void *ptr = NULL; > + uint64_t limit = 0; > + int i; > + > + if (!region->mmaps) { > + if (size) { > + *size = data_size; > + } > + return ptr; > + } > + > + for (i = 0; i < region->nr_mmaps; i++) { > + VFIOMmap *map = region->mmaps + i; > + > + if ((data_offset >= map->offset) && > + (data_offset < map->offset + map->size)) { > + > + /* check if data_offset is within sparse mmap areas */ > + ptr = map->mmap + data_offset - map->offset; > + if (size) { > + *size = MIN(data_size, map->offset + map->size - data_offset); > + } > + break; > + } else if ((data_offset < map->offset) && > + (!limit || limit > map->offset)) { > + /* > + * data_offset is not within sparse mmap areas, find size of > + * non-mapped area. Check through all list since region->mmaps list > + * is not sorted. > + */ > + limit = map->offset; > + } > + } > + > + if (!ptr && size) { > + *size = limit ? limit - data_offset : data_size; > + } > + return ptr; > +} > + > +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev, uint64_t > +*size) { > + VFIOMigration *migration = vbasedev->migration; > + VFIORegion *region = &migration->region; > + uint64_t data_offset = 0, data_size = 0, sz; > + int ret; > + > + ret = vfio_mig_read(vbasedev, &data_offset, sizeof(data_offset), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + data_offset)); > + if (ret < 0) { > + return ret; > + } > + > + ret = vfio_mig_read(vbasedev, &data_size, sizeof(data_size), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + data_size)); > + if (ret < 0) { > + return ret; > + } > + > + trace_vfio_save_buffer(vbasedev->name, data_offset, data_size, > + migration->pending_bytes); > + > + qemu_put_be64(f, data_size); > + sz = data_size; > + > + while (sz) { > + void *buf = NULL; > + uint64_t sec_size; > + bool buf_allocated = false; > + > + buf = get_data_section_size(region, data_offset, sz, > + &sec_size); > + > + if (!buf) { > + buf = g_try_malloc(sec_size); > + if (!buf) { > + error_report("%s: Error allocating buffer ", __func__); > + return -ENOMEM; > + } > + buf_allocated = true; > + > + ret = vfio_mig_read(vbasedev, buf, sec_size, > + region->fd_offset + data_offset); > + if (ret < 0) { > + g_free(buf); > + return ret; > + } > + } > + > + qemu_put_buffer(f, buf, sec_size); > + > + if (buf_allocated) { > + g_free(buf); > + } > + sz -= sec_size; > + data_offset += sec_size; > + } > + > + ret = qemu_file_get_error(f); > + > + if (!ret && size) { > + *size = data_size; > + } > + > + return ret; > +} > + > +static int vfio_update_pending(VFIODevice *vbasedev) { > + VFIOMigration *migration = vbasedev->migration; > + VFIORegion *region = &migration->region; > + uint64_t pending_bytes = 0; > + int ret; > + > + ret = vfio_mig_read(vbasedev, &pending_bytes, sizeof(pending_bytes), > + region->fd_offset + offsetof(struct vfio_device_migration_info, > + pending_bytes)); > + if (ret < 0) { > + migration->pending_bytes = 0; > + return ret; > + } > + > + 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) @@ -232,9 +380,134 @@ 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; > + uint64_t data_size; > + int ret; > + > + 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 */ > + return 1; > + } > + } > + > + ret = vfio_save_buffer(f, vbasedev, &data_size); > + > + if (ret) { > + error_report("%s: vfio_save_buffer failed %s", vbasedev->name, > + strerror(errno)); > + return ret; > + } > + > + 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; > + uint64_t data_size; > + 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, &data_size); > + if (ret < 0) { > + error_report("%s: Failed to save buffer", vbasedev->name); > + return ret; > + } > + > + if (data_size == 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 982d8dccb219..118b5547c921 100644 > --- a/hw/vfio/trace-events > +++ b/hw/vfio/trace-events > @@ -154,3 +154,9 @@ 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 49c7c7a0e29a..471e444a364c 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 >