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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 EBB85C432C3 for ; Thu, 14 Nov 2019 05:05:36 +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 9D008206E1 for ; Thu, 14 Nov 2019 05:05:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IW8RKRWW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9D008206E1 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]:53442 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iV7K3-0007JV-KA for qemu-devel@archiver.kernel.org; Thu, 14 Nov 2019 00:05:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41799) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iV7J1-0006Pf-Qh for qemu-devel@nongnu.org; Thu, 14 Nov 2019 00:04:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iV7Iz-0004GS-KD for qemu-devel@nongnu.org; Thu, 14 Nov 2019 00:04:31 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:51100 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iV7Iz-0004FT-FE for qemu-devel@nongnu.org; Thu, 14 Nov 2019 00:04:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573707868; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CsjrsuILU7z08vjaqiiSVT5hqKnzgr53t+45JTsReaI=; b=IW8RKRWWW3uA9UoYQLxbUfzeW6YbDZuNpi3HtzG9lviufarz73JXvEw2liOL8xNkv6BP0V DBQ98wM5ehzv7jyKeEAyzr2GHWvT6RbZPl4bYvAquR5M5dPw3/Q8pv7TUY2cMasf1Ovt2w tb1JjBPFdlfW/CPjRs4HtcwpTQzThYI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-313-hNRNs5-fP3mqSN4ABK0qIQ-1; Thu, 14 Nov 2019 00:04:23 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 06D51800A1A; Thu, 14 Nov 2019 05:04:20 +0000 (UTC) Received: from x1.home (ovpn-116-138.phx2.redhat.com [10.3.116.138]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9B4545F77D; Thu, 14 Nov 2019 05:04:18 +0000 (UTC) Date: Wed, 13 Nov 2019 22:04:18 -0700 From: Alex Williamson To: Kirti Wankhede Subject: Re: [PATCH v9 QEMU 11/15] vfio: Add save state functions to SaveVMHandlers Message-ID: <20191113220418.081244d6@x1.home> In-Reply-To: <1573578324-8389-12-git-send-email-kwankhede@nvidia.com> References: <1573578324-8389-1-git-send-email-kwankhede@nvidia.com> <1573578324-8389-12-git-send-email-kwankhede@nvidia.com> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: hNRNs5-fP3mqSN4ABK0qIQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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, qemu-devel@nongnu.org, cohuck@redhat.com, shuangtai.tst@alibaba-inc.com, dgilbert@redhat.com, zhi.a.wang@intel.com, mlevitsk@redhat.com, pasic@linux.ibm.com, aik@ozlabs.ru, 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" On Tue, 12 Nov 2019 22:35:20 +0530 Kirti Wankhede wrote: > Added .save_live_pending, .save_live_iterate and .save_live_complete_prec= opy > functions. These functions handles pre-copy and stop-and-copy phase. >=20 > 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 } >=20 > 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} >=20 > When data region is mapped, its user's responsibility to read data from s/mapped/made available/ "mapped" is confusing given the mmap'd features. > data_offset of data_size before moving to next steps. > > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > hw/vfio/migration.c | 245 +++++++++++++++++++++++++++++++++++++++++++++= +++++- > hw/vfio/trace-events | 6 ++ > 2 files changed, 250 insertions(+), 1 deletion(-) >=20 > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 48aac6d29876..f890e864e174 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -120,6 +120,137 @@ static int vfio_migration_set_state(VFIODevice *vba= sedev, uint32_t set_flags, > return 0; > } > =20 > +static void *find_data_region(VFIORegion *region, > + uint64_t data_offset, > + uint64_t data_size) > +{ > + void *ptr =3D NULL; > + int i; > + > + for (i =3D 0; i < region->nr_mmaps; i++) { > + if ((data_offset >=3D region->mmaps[i].offset) && > + (data_offset < region->mmaps[i].offset + region->mmaps[i].si= ze) && > + (data_size <=3D region->mmaps[i].size)) { data_offset is determined to live somewhere within the mmap and data_size is independently determined to be smaller than the entire mmaps size. This is broken. > + ptr =3D region->mmaps[i].mmap + (data_offset - > + region->mmaps[i].offset); If the data offset is mmap'd, this gives us a pointer to the start, but we have no idea if the entire range is accessible via this pointer, nor does the API require it to be. > + break; > + } > + } > + return ptr; > +} > + > +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev) > +{ > + VFIOMigration *migration =3D vbasedev->migration; > + VFIORegion *region =3D &migration->region; > + uint64_t data_offset =3D 0, data_size =3D 0; > + int ret; > + > + ret =3D pread(vbasedev->fd, &data_offset, sizeof(data_offset), > + region->fd_offset + offsetof(struct vfio_device_migratio= n_info, > + data_offset)); > + if (ret !=3D sizeof(data_offset)) { > + error_report("%s: Failed to get migration buffer data offset %d"= , > + vbasedev->name, ret); > + return -EINVAL; > + } > + > + ret =3D pread(vbasedev->fd, &data_size, sizeof(data_size), > + region->fd_offset + offsetof(struct vfio_device_migratio= n_info, > + data_size)); > + if (ret !=3D 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 =3D NULL; > + bool buffer_mmaped; > + > + if (region->mmaps) { > + buf =3D find_data_region(region, data_offset, data_size); > + } > + > + buffer_mmaped =3D (buf !=3D NULL) ? true : false; > + > + if (!buffer_mmaped) { > + buf =3D g_try_malloc0(data_size); > + if (!buf) { > + error_report("%s: Error allocating buffer ", __func__); > + return -ENOMEM; > + } > + > + ret =3D pread(vbasedev->fd, buf, data_size, > + region->fd_offset + data_offset); > + if (ret !=3D data_size) { > + error_report("%s: Failed to get migration data %d", > + vbasedev->name, ret); > + g_free(buf); > + return -EINVAL; > + } Seems like this needs to be bound and chunked to some "reasonable" size, the vendor driver could be exposing gigabytes of data at a time. Do we have a quota for this phase? > + } > + > + 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); Why would we stuff zero or <0 into the data stream here? > + } There's clearly an assumption here that a chunk of data from the device is entirely mmap'd or not. That's not a requirement of the API and I believe we've discussed cases where a vendor driver could have partially mapped and partially emulated data chunks. > + > + trace_vfio_save_buffer(vbasedev->name, data_offset, data_size, > + migration->pending_bytes); > + > + ret =3D qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + return data_size; AIUI, it's required to read pending_bytes to indicate the data has been consumed, I don't see that done here. > +} > + > +static int vfio_update_pending(VFIODevice *vbasedev) > +{ > + VFIOMigration *migration =3D vbasedev->migration; > + VFIORegion *region =3D &migration->region; > + uint64_t pending_bytes =3D 0; > + int ret; > + > + ret =3D pread(vbasedev->fd, &pending_bytes, sizeof(pending_bytes), > + region->fd_offset + offsetof(struct vfio_device_migratio= n_info, > + pending_bytes)); > + if ((ret < 0) || (ret !=3D sizeof(pending_bytes))) { Two tests for the same thing. > + error_report("%s: Failed to get pending bytes %d", > + vbasedev->name, ret); > + migration->pending_bytes =3D 0; > + return (ret < 0) ? ret : -EINVAL; pread returns -1 on error and sets errno, the ret value isn't very interesting. > + } > + > + migration->pending_bytes =3D 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 =3D opaque; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE); > + > + if (vbasedev->ops && vbasedev->ops->vfio_save_config) { A vbasedev w/o ops doesn't seem possible. > + vbasedev->ops->vfio_save_config(vbasedev, f); > + } > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); Is it worthwhile to include these markers w/o vfio_save_config? Couldn't we simply move them into the conditional section? > + > + trace_vfio_save_device_config_state(vbasedev->name); > + > + return qemu_file_get_error(f); > +} > + > /* ---------------------------------------------------------------------= - */ > =20 > static int vfio_save_setup(QEMUFile *f, void *opaque) > @@ -136,7 +267,7 @@ 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, Fix this in patch that introduced it, looks like this wouldn't even compile previously. > strerror(-ret)); > return ret; > } > @@ -170,9 +301,121 @@ static void vfio_save_cleanup(void *opaque) > trace_vfio_save_cleanup(vbasedev->name); > } > =20 > +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 =3D opaque; > + VFIOMigration *migration =3D vbasedev->migration; > + int ret; > + > + ret =3D vfio_update_pending(vbasedev); > + if (ret) { > + return; > + } > + > + *res_precopy_only +=3D 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 =3D opaque; > + int ret, data_size; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); > + > + data_size =3D 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 =3D qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + trace_vfio_save_iterate(vbasedev->name, data_size); > + if (data_size =3D=3D 0) { > + /* indicates data finished, goto complete phase */ > + return 1; > + } I don't think this matches our spec, pending_bytes seems to indicate we've finished, data_size of zero does not have a defined meaning. > + > + return 0; > +} > + > +static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev =3D opaque; > + VFIOMigration *migration =3D vbasedev->migration; > + int ret; > + > + ret =3D vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_SAVING, > + VFIO_DEVICE_STATE_RUNNING); > + if (ret) { > + error_report("%s: Failed to set state STOP and SAVING", > + vbasedev->name); > + return ret; > + } > + > + ret =3D vfio_save_device_config_state(f, opaque); > + if (ret) { > + return ret; > + } > + > + ret =3D vfio_update_pending(vbasedev); > + if (ret) { > + return ret; > + } > + > + while (migration->pending_bytes > 0) { > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); > + ret =3D vfio_save_buffer(f, vbasedev); > + if (ret < 0) { > + error_report("%s: Failed to save buffer", vbasedev->name); > + return ret; > + } else if (ret =3D=3D 0) { > + break; > + } > + > + ret =3D vfio_update_pending(vbasedev); > + if (ret) { > + return ret; > + } > + } Here we use pending_bytes for the stop condition and update pending_bytes per loop, which is different than the above save iterate function. > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); > + > + ret =3D qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + ret =3D vfio_migration_set_state(vbasedev, 0, VFIO_DEVICE_STATE_SAVI= NG); > + 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 =3D { > .save_setup =3D vfio_save_setup, > .save_cleanup =3D vfio_save_cleanup, > + .save_live_pending =3D vfio_save_pending, > + .save_live_iterate =3D vfio_save_iterate, > + .save_live_complete_precopy =3D vfio_save_complete_precopy, > }; > =20 > /* ---------------------------------------------------------------------= - */ > 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 ch= ar *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, u= int64_t pending) " (%s) Offset 0x%"PRIx64" size 0x%"PRIx64" pending 0x%"PRI= x64 > +vfio_update_pending(char *name, uint64_t pending) " (%s) pending 0x%"PRI= x64 > +vfio_save_device_config_state(char *name) " (%s)" > +vfio_save_pending(char *name, uint64_t precopy, uint64_t postcopy, uint6= 4_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)"