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Wed, 1 Apr 2020 17:36:50 +0000 (UTC) Received: from work-vm (ovpn-115-201.ams2.redhat.com [10.36.115.201]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 313665C3F8; Wed, 1 Apr 2020 17:36:43 +0000 (UTC) Date: Wed, 1 Apr 2020 18:36:40 +0100 From: "Dr. David Alan Gilbert" To: Kirti Wankhede Subject: Re: [PATCH v16 QEMU 08/16] vfio: Register SaveVMHandlers for VFIO device Message-ID: <20200401173640.GG52559@work-vm> References: <1585084154-29461-1-git-send-email-kwankhede@nvidia.com> <1585084154-29461-9-git-send-email-kwankhede@nvidia.com> MIME-Version: 1.0 In-Reply-To: <1585084154-29461-9-git-send-email-kwankhede@nvidia.com> User-Agent: Mutt/1.13.4 (2020-02-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline 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, 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: > Define flags to be used as delimeter in migration file stream. > Added .save_setup and .save_cleanup functions. Mapped & unmapped migratio= n > region from these functions at source during saving or pre-copy phase. > Set VFIO device state depending on VM's state. During live migration, VM = is > running when .save_setup is called, _SAVING | _RUNNING state is set for V= FIO > device. During save-restore, VM is paused, _SAVING state is set for VFIO = device. >=20 > Signed-off-by: Kirti Wankhede > Reviewed-by: Neo Jia > --- > hw/vfio/migration.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++= ++++++ > hw/vfio/trace-events | 2 ++ > 2 files changed, 78 insertions(+) >=20 > diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > index 22ded9d28cf3..033f76526e49 100644 > --- a/hw/vfio/migration.c > +++ b/hw/vfio/migration.c > @@ -8,6 +8,7 @@ > */ > =20 > #include "qemu/osdep.h" > +#include "qemu/main-loop.h" > #include > =20 > #include "sysemu/runstate.h" > @@ -24,6 +25,17 @@ > #include "pci.h" > #include "trace.h" > =20 > +/* > + * Flags used as delimiter: > + * 0xffffffff =3D> MSB 32-bit all 1s > + * 0xef10 =3D> emulated (virtual) function IO > + * 0x0000 =3D> 16-bits reserved for flags > + */ > +#define VFIO_MIG_FLAG_END_OF_STATE (0xffffffffef100001ULL) > +#define VFIO_MIG_FLAG_DEV_CONFIG_STATE (0xffffffffef100002ULL) > +#define VFIO_MIG_FLAG_DEV_SETUP_STATE (0xffffffffef100003ULL) > +#define VFIO_MIG_FLAG_DEV_DATA_STATE (0xffffffffef100004ULL) > + > static void vfio_migration_region_exit(VFIODevice *vbasedev) > { > VFIOMigration *migration =3D vbasedev->migration; > @@ -126,6 +138,69 @@ static int vfio_migration_set_state(VFIODevice *vbas= edev, uint32_t mask, > return 0; > } > =20 > +/* ---------------------------------------------------------------------= - */ > + > +static int vfio_save_setup(QEMUFile *f, void *opaque) > +{ > + VFIODevice *vbasedev =3D opaque; > + VFIOMigration *migration =3D vbasedev->migration; > + int ret; > + > + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE); > + > + if (migration->region.mmaps) { > + qemu_mutex_lock_iothread(); > + ret =3D vfio_region_mmap(&migration->region); > + qemu_mutex_unlock_iothread(); > + if (ret) { > + error_report("%s: Failed to mmap VFIO migration region %d: %= s", > + vbasedev->name, migration->region.index, > + strerror(-ret)); > + return ret; > + } > + } > + > + ret =3D vfio_migration_set_state(vbasedev, ~0, VFIO_DEVICE_STATE_SAV= ING); > + if (ret) { > + error_report("%s: Failed to set state SAVING", vbasedev->name); > + return ret; > + } > + > + /* > + * Save migration region size. This is used to verify migration regi= on size > + * is greater than or equal to migration region size at destination > + */ > + qemu_put_be64(f, migration->region.size); > + > + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE); OK, good, so now we can change that to something else if you want to migrate something extra in the future. > + ret =3D qemu_file_get_error(f); > + if (ret) { > + return ret; > + } > + > + trace_vfio_save_setup(vbasedev->name); I'd put that trace at the start of the function. > + return 0; > +} > + > +static void vfio_save_cleanup(void *opaque) > +{ > + VFIODevice *vbasedev =3D opaque; > + VFIOMigration *migration =3D vbasedev->migration; > + > + if (migration->region.mmaps) { > + vfio_region_unmap(&migration->region); > + } > + trace_vfio_save_cleanup(vbasedev->name); > +} > + > +static SaveVMHandlers savevm_vfio_handlers =3D { > + .save_setup =3D vfio_save_setup, > + .save_cleanup =3D vfio_save_cleanup, > +}; > + > +/* ---------------------------------------------------------------------= - */ > + > static void vfio_vmstate_change(void *opaque, int running, RunState stat= e) > { > VFIODevice *vbasedev =3D opaque; > @@ -191,6 +266,7 @@ static int vfio_migration_init(VFIODevice *vbasedev, > return ret; > } > =20 > + register_savevm_live("vfio", -1, 1, &savevm_vfio_handlers, vbasedev)= ; That doesn't look right to me; firstly the -1 should now be VMSTATE_INSTANCE_ID_ANY - after the recent change in commit 1df2c9a Have you tried this with two vfio devices? This is quite rare - it's an iterative device that can have multiple instances; if you look at 'ram' for example, all the RAM instances are handled inside the save_setup/save for the one instance of 'ram'. I think here you're trying to register an individual vfio device, so if you had multiple devices you'd see this called twice. So either you need to make vfio_save_* do all of the devices in a loop - which feels like a bad idea; or replace "vfio" in that call by a unique device name; as long as your device has a bus path then you should be able to use the same trick vmstate_register_with_alias_id does, and use I think, vmstate_if_get_id(VMSTAETE_IF(vbasedev)). but it might take some experimentation since this is an odd use. > vbasedev->vm_state =3D qemu_add_vm_change_state_handler(vfio_vmstate= _change, > vbasedev); > =20 > diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events > index 69503228f20e..4bb43f18f315 100644 > --- a/hw/vfio/trace-events > +++ b/hw/vfio/trace-events > @@ -149,3 +149,5 @@ vfio_migration_probe(char *name, uint32_t index) " (%= s) Region %d" > vfio_migration_set_state(char *name, uint32_t state) " (%s) state %d" > vfio_vmstate_change(char *name, int running, const char *reason, uint32_= t dev_state) " (%s) running %d reason %s device state %d" > vfio_migration_state_notifier(char *name, int state) " (%s) state %d" > +vfio_save_setup(char *name) " (%s)" > +vfio_save_cleanup(char *name) " (%s)" > --=20 > 2.7.0 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK