From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F013C4321A for ; Fri, 28 Jun 2019 09:11:35 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6673C208CB for ; Fri, 28 Jun 2019 09:11:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6673C208CB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57930 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgmus-0005JF-MZ for qemu-devel@archiver.kernel.org; Fri, 28 Jun 2019 05:11:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41522) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hgmtR-0004E9-Tm for qemu-devel@nongnu.org; Fri, 28 Jun 2019 05:10:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hgmtQ-0007go-0A for qemu-devel@nongnu.org; Fri, 28 Jun 2019 05:10:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58076) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hgmtP-0007fg-G8 for qemu-devel@nongnu.org; Fri, 28 Jun 2019 05:10:03 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 56DE6C047B7A; Fri, 28 Jun 2019 09:10:00 +0000 (UTC) Received: from work-vm (ovpn-116-169.ams2.redhat.com [10.36.116.169]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 287041A7C8; Fri, 28 Jun 2019 09:09:50 +0000 (UTC) Date: Fri, 28 Jun 2019 10:09:48 +0100 From: "Dr. David Alan Gilbert" To: Kirti Wankhede Message-ID: <20190628090948.GB2922@work-vm> References: <1561041461-22326-1-git-send-email-kwankhede@nvidia.com> <1561041461-22326-9-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1561041461-22326-9-git-send-email-kwankhede@nvidia.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 28 Jun 2019 09:10:00 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v4 08/13] 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: , Cc: Zhengxiao.zx@alibaba-inc.com, kevin.tian@intel.com, yi.l.liu@intel.com, cjia@nvidia.com, eskultet@redhat.com, ziye.yang@intel.com, yulei.zhang@intel.com, cohuck@redhat.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, alex.williamson@redhat.com, eauger@redhat.com, felipe@nutanix.com, jonathan.davies@nutanix.com, yan.y.zhao@intel.com, changpeng.liu@intel.com, Ken.Xue@amd.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 > - 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() number of bytes in data_size, from > data_offset. > - if data section is mmaped, read mmaped buffer of size 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 - indicates kernel driver to write data to staging > buffer which is mmapped. > c. read data_size - amount of data in bytes written by vendor driver in > migration region. > d. if data section is trapped, pread() from data_offset of size data_size. > e. if data section is mmaped, read mmaped buffer of size data_size. > f. Write data packet as below: > {VFIO_MIG_FLAG_DEV_DATA_STATE, data_size, actual data} > g. iterate through steps b to f until (pending_bytes > 0) > h. Write {VFIO_MIG_FLAG_END_OF_STATE} > > .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 | 212 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 212 insertions(+) > > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index fe0887c27664..0a2f30872316 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -107,6 +107,111 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t state) > return 0; > } > > +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("Failed to get migration buffer data offset %d", > + ret); > + return -EINVAL; > + } It feels like you need a helper function, something so that you can do something like: if (!vfio_dev_read(vbasedev, &data_offset, sizeof(data_offset), region->fd_offset + offsetof(struct vfio_device_migration_info, data_offset), "data offset")) { 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("Failed to get migration buffer data size %d", > + ret); > + return -EINVAL; > + } > + > + if (data_size > 0) { > + void *buf = NULL; > + bool buffer_mmaped = false; > + > + if (region->mmaps) { > + 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)) { > + buf = region->mmaps[i].mmap + (data_offset - > + region->mmaps[i].offset); > + buffer_mmaped = true; > + break; > + } > + } > + } > + > + if (!buffer_mmaped) { > + buf = g_malloc0(data_size); > + ret = pread(vbasedev->fd, buf, data_size, > + region->fd_offset + data_offset); > + if (ret != data_size) { > + error_report("Failed to get migration data %d", 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; > + } else { > + qemu_put_be64(f, data_size); > + } > + > + ret = qemu_file_get_error(f); You're ignoring that return value; it's not that important to check for errors on the saving side - although you should if you're looping on data to fail quickly; it's more of an issue on the load side. > + 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("Failed to get pending bytes %d", ret); > + migration->pending_bytes = 0; > + return (ret < 0) ? ret : -EINVAL; > + } > + > + migration->pending_bytes = 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->type == VFIO_DEVICE_TYPE_PCI) { > + vfio_pci_save_config(vbasedev, f); > + } > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + return qemu_file_get_error(f); > +} > + > /* ---------------------------------------------------------------------- */ > > static int vfio_save_setup(QEMUFile *f, void *opaque) > @@ -163,9 +268,116 @@ static void vfio_save_cleanup(void *opaque) > } > } > > +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; > + } > + > + if (vbasedev->device_state & VFIO_DEVICE_STATE_RUNNING) { > + *res_precopy_only += migration->pending_bytes; > + } else { > + *res_postcopy_only += migration->pending_bytes; > + } > + *res_compatible += 0; > +} > + > +static int vfio_save_iterate(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev = opaque; > + VFIOMigration *migration = vbasedev->migration; > + int ret; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); > + > + qemu_mutex_lock(&migration->lock); > + ret = vfio_save_buffer(f, vbasedev); > + qemu_mutex_unlock(&migration->lock); > + > + if (ret < 0) { > + error_report("vfio_save_buffer failed %s", > + strerror(errno)); > + return ret; > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + ret = qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + return ret; > +} > + > +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("Failed to set state STOP and SAVING"); > + 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("Failed to save buffer"); > + 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_STOPPED); > + if (ret) { > + error_report("Failed to set state STOPPED"); > + return ret; > + } > + 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, > }; > > /* ---------------------------------------------------------------------- */ > -- > 2.7.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK