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auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=63.128.21.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/20 01:15:43 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, 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: 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, "Dr. David Alan Gilbert" , 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" On Sun, 18 Oct 2020 01:54:56 +0530 Kirti Wankhede wrote: > On 9/29/2020 4:33 PM, Dr. David Alan Gilbert wrote: > > * Cornelia Huck (cohuck@redhat.com) wrote: > >> On Wed, 23 Sep 2020 04:54:07 +0530 > >> Kirti Wankhede wrote: > >> > >>> VM state change handler gets called on change in VM's state. This is used to set > >>> VFIO device state to _RUNNING. > >>> > >>> Signed-off-by: Kirti Wankhede > >>> Reviewed-by: Neo Jia > >>> Reviewed-by: Dr. David Alan Gilbert > >>> --- > >>> hw/vfio/migration.c | 136 ++++++++++++++++++++++++++++++++++++++++++ > >>> hw/vfio/trace-events | 3 +- > >>> include/hw/vfio/vfio-common.h | 4 ++ > >>> 3 files changed, 142 insertions(+), 1 deletion(-) > >>> > >> > >> (...) > >> > >>> +static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, > >>> + uint32_t value) > >> > >> I think I've mentioned that before, but this function could really > >> benefit from a comment what mask and value mean. > >> > > Adding a comment as: > > /* > * Write device_state field to inform the vendor driver about the > device state > * to be transitioned to. > * vbasedev: VFIO device > * mask : bits set in the mask are preserved in device_state > * value: bits set in the value are set in device_state > * Remaining bits in device_state are cleared. > */ Maybe: "Change the device_state register for device @vbasedev. Bits set in @mask are preserved, bits set in @value are set, and bits not set in either @mask or @value are cleared in device_state. If the register cannot be accessed, the resulting state would be invalid, or the device enters an error state, an error is returned." ? > > > >>> +{ > >>> + VFIOMigration *migration = vbasedev->migration; > >>> + VFIORegion *region = &migration->region; > >>> + off_t dev_state_off = region->fd_offset + > >>> + offsetof(struct vfio_device_migration_info, device_state); > >>> + uint32_t device_state; > >>> + int ret; > >>> + > >>> + ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state), > >>> + dev_state_off); > >>> + if (ret < 0) { > >>> + return ret; > >>> + } > >>> + > >>> + device_state = (device_state & mask) | value; > >>> + > >>> + if (!VFIO_DEVICE_STATE_VALID(device_state)) { > >>> + return -EINVAL; > >>> + } > >>> + > >>> + ret = vfio_mig_write(vbasedev, &device_state, sizeof(device_state), > >>> + dev_state_off); > >>> + if (ret < 0) { > >>> + ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state), > >>> + dev_state_off); > >>> + if (ret < 0) { > >>> + return ret; > >>> + } > >>> + > >>> + if (VFIO_DEVICE_STATE_IS_ERROR(device_state)) { > >>> + hw_error("%s: Device is in error state 0x%x", > >>> + vbasedev->name, device_state); > >>> + return -EFAULT; > >> > >> Is -EFAULT a good return value here? Maybe -EIO? > >> > > Ok. Changing to -EIO. > > >>> + } > >>> + } > >>> + > >>> + vbasedev->device_state = device_state; > >>> + trace_vfio_migration_set_state(vbasedev->name, device_state); > >>> + return 0; > >>> +} > >>> + > >>> +static void vfio_vmstate_change(void *opaque, int running, RunState state) > >>> +{ > >>> + VFIODevice *vbasedev = opaque; > >>> + > >>> + if ((vbasedev->vm_running != running)) { > >>> + int ret; > >>> + uint32_t value = 0, mask = 0; > >>> + > >>> + if (running) { > >>> + value = VFIO_DEVICE_STATE_RUNNING; > >>> + if (vbasedev->device_state & VFIO_DEVICE_STATE_RESUMING) { > >>> + mask = ~VFIO_DEVICE_STATE_RESUMING; > >> > >> I've been staring at this for some time and I think that the desired > >> result is > >> - set _RUNNING > >> - if _RESUMING was set, clear it, but leave the other bits intact > > Upto here, you're correct. > > >> - if _RESUMING was not set, clear everything previously set > >> This would really benefit from a comment (or am I the only one > >> struggling here?) > >> > > Here mask should be ~0. Correcting it. Hm, now I'm confused. With value == _RUNNING, ~_RUNNING and ~0 as mask should be equivalent, shouldn't they? > > > >>> + } > >>> + } else { > >>> + mask = ~VFIO_DEVICE_STATE_RUNNING; > >>> + } > >>> + > >>> + ret = vfio_migration_set_state(vbasedev, mask, value); > >>> + if (ret) { > >>> + /* > >>> + * vm_state_notify() doesn't support reporting failure. If such > >>> + * error reporting support added in furure, migration should be > >>> + * aborted. > >> > >> > >> "We should abort the migration in this case, but vm_state_notify() > >> currently does not support reporting failures." > >> > >> ? > >> > > Ok. Updating comment as suggested here. > > >> Can/should we mark the failing device in some way? > > > > I think you can call qemu_file_set_error on the migration stream to > > force an error. > > > > It should be as below, right? > qemu_file_set_error(migrate_get_current()->to_dst_file, ret); Does this indicate in any way which device was causing problems? (I'm not sure how visible the error_report would be?) > > > Thanks, > Kirti > > > Dave > > > >>> + */ > >>> + error_report("%s: Failed to set device state 0x%x", > >>> + vbasedev->name, value & mask); > >>> + } > >>> + vbasedev->vm_running = running; > >>> + trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state), > >>> + value & mask); > >>> + } > >>> +} > >>> + > >>> static int vfio_migration_init(VFIODevice *vbasedev, > >>> struct vfio_region_info *info) > >>> { > >> > >> (...) >