From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: cjia@nvidia.com, aik@ozlabs.ru, Zhengxiao.zx@alibaba-inc.com,
shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org,
peterx@redhat.com, Kirti Wankhede <kwankhede@nvidia.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,
alex.williamson@redhat.com, changpeng.liu@intel.com,
eskultet@redhat.com, Ken.Xue@amd.com,
jonathan.davies@nutanix.com, pbonzini@redhat.com
Subject: Re: [PATCH v26 05/17] vfio: Add VM state change handler to know state of VM
Date: Tue, 29 Sep 2020 12:03:12 +0100 [thread overview]
Message-ID: <20200929110312.GF2826@work-vm> (raw)
In-Reply-To: <20200924170220.0a9836fe.cohuck@redhat.com>
* Cornelia Huck (cohuck@redhat.com) wrote:
> On Wed, 23 Sep 2020 04:54:07 +0530
> Kirti Wankhede <kwankhede@nvidia.com> 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 <kwankhede@nvidia.com>
> > Reviewed-by: Neo Jia <cjia@nvidia.com>
> > Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> > 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.
>
> > +{
> > + 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?
>
> > + }
> > + }
> > +
> > + 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
> - if _RESUMING was not set, clear everything previously set
> This would really benefit from a comment (or am I the only one
> struggling here?)
>
> > + }
> > + } 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."
>
> ?
>
> 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.
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)
> > {
>
> (...)
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2020-09-29 11:08 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 23:24 [PATCH QEMU v25 00/17] Add migration support for VFIO devices Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 01/17] vfio: Add function to unmap VFIO region Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 02/17] vfio: Add vfio_get_object callback to VFIODeviceOps Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 03/17] vfio: Add save and load functions for VFIO PCI devices Kirti Wankhede
2020-09-23 6:38 ` Zenghui Yu
2020-09-24 22:49 ` Alex Williamson
2020-10-21 9:30 ` Zenghui Yu
2020-10-21 19:03 ` Alex Williamson
2020-09-22 23:24 ` [PATCH v26 04/17] vfio: Add migration region initialization and finalize function Kirti Wankhede
2020-09-24 14:08 ` Cornelia Huck
2020-10-17 20:14 ` Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-09-28 9:39 ` Cornelia Huck
2020-10-17 20:17 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 05/17] vfio: Add VM state change handler to know state of VM Kirti Wankhede
2020-09-24 15:02 ` Cornelia Huck
2020-09-29 11:03 ` Dr. David Alan Gilbert [this message]
2020-10-17 20:24 ` Kirti Wankhede
2020-10-20 10:51 ` Cornelia Huck
2020-10-21 5:33 ` Kirti Wankhede
2020-10-22 7:51 ` Cornelia Huck
2020-10-22 15:42 ` Kirti Wankhede
2020-10-22 15:49 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:30 ` Kirti Wankhede
2020-10-17 23:44 ` Alex Williamson
2020-10-18 17:43 ` Kirti Wankhede
2020-10-19 17:51 ` Alex Williamson
2020-10-20 10:23 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 06/17] vfio: Add migration state change notifier Kirti Wankhede
2020-09-25 20:20 ` Alex Williamson
2020-10-17 20:35 ` Kirti Wankhede
2020-10-19 17:57 ` Alex Williamson
2020-10-20 10:55 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 07/17] vfio: Register SaveVMHandlers for VFIO device Kirti Wankhede
2020-09-24 15:15 ` Philippe Mathieu-Daudé
2020-09-29 10:19 ` Dr. David Alan Gilbert
2020-10-17 20:36 ` Kirti Wankhede
2020-09-25 11:53 ` Cornelia Huck
2020-10-18 20:55 ` Kirti Wankhede
2020-10-20 15:51 ` Cornelia Huck
2020-09-25 20:20 ` Alex Williamson
2020-10-18 17:40 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 08/17] vfio: Add save state functions to SaveVMHandlers Kirti Wankhede
2020-09-23 11:42 ` Wang, Zhi A
2020-10-21 14:30 ` Kirti Wankhede
2020-09-25 21:02 ` Alex Williamson
2020-10-18 18:00 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 09/17] vfio: Add load " Kirti Wankhede
2020-10-01 10:07 ` Cornelia Huck
2020-10-18 20:47 ` Kirti Wankhede
2020-10-20 16:25 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 10/17] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 11/17] vfio: Get migration capability flags for container Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 12/17] vfio: Add function to start and stop dirty pages tracking Kirti Wankhede
2020-09-25 21:55 ` Alex Williamson
2020-10-18 20:52 ` Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 13/17] vfio: create mapped iova list when vIOMMU is enabled Kirti Wankhede
2020-09-25 22:23 ` Alex Williamson
2020-10-19 6:01 ` Kirti Wankhede
2020-10-19 17:24 ` Alex Williamson
2020-10-19 19:15 ` Kirti Wankhede
2020-10-19 20:07 ` Alex Williamson
2020-09-22 23:24 ` [PATCH v26 14/17] vfio: Add vfio_listener_log_sync to mark dirty pages Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 15/17] vfio: Add ioctl to get dirty pages bitmap during dma unmap Kirti Wankhede
2020-09-22 23:24 ` [PATCH v26 16/17] vfio: Make vfio-pci device migration capable Kirti Wankhede
2020-09-25 12:17 ` Cornelia Huck
2020-09-22 23:24 ` [PATCH v26 17/17] qapi: Add VFIO devices migration stats in Migration stats Kirti Wankhede
2020-09-24 15:14 ` Eric Blake
2020-09-25 22:55 ` Alex Williamson
2020-09-29 10:40 ` Dr. David Alan Gilbert
2020-09-23 7:06 ` [PATCH QEMU v25 00/17] Add migration support for VFIO devices Zenghui Yu
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