From: Kirti Wankhede <kwankhede@nvidia.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, 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,
dgilbert@redhat.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 09/17] vfio: Add load state functions to SaveVMHandlers
Date: Mon, 19 Oct 2020 02:17:43 +0530 [thread overview]
Message-ID: <5ca09cd6-efd6-ed8d-277f-5a1b42b5835c@nvidia.com> (raw)
In-Reply-To: <20201001120730.36eb76dd.cohuck@redhat.com>
On 10/1/2020 3:37 PM, Cornelia Huck wrote:
> On Wed, 23 Sep 2020 04:54:11 +0530
> Kirti Wankhede <kwankhede@nvidia.com> wrote:
>
>> Sequence during _RESUMING device state:
>> While data for this device is available, repeat below steps:
>> a. read data_offset from where user application should write data.
>> b. write data of data_size to migration region from data_offset.
>> c. write data_size which indicates vendor driver that data is written in
>> staging buffer.
>>
>> For user, data is opaque. User should write data in the same order as
>> received.
>>
>> 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 | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> hw/vfio/trace-events | 3 +
>> 2 files changed, 173 insertions(+)
>>
>> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
>> index 4611bb972228..ffd70282dd0e 100644
>> --- a/hw/vfio/migration.c
>> +++ b/hw/vfio/migration.c
>> @@ -328,6 +328,33 @@ static int vfio_save_device_config_state(QEMUFile *f, void *opaque)
>> return qemu_file_get_error(f);
>> }
>>
>> +static int vfio_load_device_config_state(QEMUFile *f, void *opaque)
>> +{
>> + VFIODevice *vbasedev = opaque;
>> + uint64_t data;
>> +
>> + if (vbasedev->ops && vbasedev->ops->vfio_load_config) {
>> + int ret;
>> +
>> + ret = vbasedev->ops->vfio_load_config(vbasedev, f);
>> + if (ret) {
>> + error_report("%s: Failed to load device config space",
>> + vbasedev->name);
>> + return ret;
>> + }
>> + }
>> +
>> + data = qemu_get_be64(f);
>> + if (data != VFIO_MIG_FLAG_END_OF_STATE) {
>> + error_report("%s: Failed loading device config space, "
>> + "end flag incorrect 0x%"PRIx64, vbasedev->name, data);
>
> I'm confused here: If we don't have a vfio_load_config callback, or if
> that callback did not read everything, we also might end up with a
> value that's not END_OF_STATE... in that case, the problem is not with
> the stream, but rather with the consumer?
Right, hence "end flag incorrect" is reported.
>
>> + return -EINVAL;
>> + }
>> +
>> + trace_vfio_load_device_config_state(vbasedev->name);
>> + return qemu_file_get_error(f);
>> +}
>> +
>> /* ---------------------------------------------------------------------- */
>>
>> static int vfio_save_setup(QEMUFile *f, void *opaque)
>> @@ -502,12 +529,155 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
>> return ret;
>> }
>>
>> +static int vfio_load_setup(QEMUFile *f, void *opaque)
>> +{
>> + VFIODevice *vbasedev = opaque;
>> + VFIOMigration *migration = vbasedev->migration;
>> + int ret = 0;
>> +
>> + if (migration->region.mmaps) {
>> + ret = vfio_region_mmap(&migration->region);
>> + if (ret) {
>> + error_report("%s: Failed to mmap VFIO migration region %d: %s",
>> + vbasedev->name, migration->region.nr,
>> + strerror(-ret));
>> + error_report("%s: Falling back to slow path", vbasedev->name);
>> + }
>> + }
>> +
>> + ret = vfio_migration_set_state(vbasedev, ~VFIO_DEVICE_STATE_MASK,
>> + VFIO_DEVICE_STATE_RESUMING);
>> + if (ret) {
>> + error_report("%s: Failed to set state RESUMING", vbasedev->name);
>> + }
>> + return ret;
>
> If I follow the code correctly, the cleanup callback will not be
> invoked if you return != 0 here... should you clean up possible
> mappings on error here?
>
Makes sense, adding region ummap on error.
>> +}
>> +
>> +static int vfio_load_cleanup(void *opaque)
>> +{
>> + vfio_save_cleanup(opaque);
>> + return 0;
>> +}
>> +
>> +static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
>> +{
>> + VFIODevice *vbasedev = opaque;
>> + VFIOMigration *migration = vbasedev->migration;
>> + int ret = 0;
>> + uint64_t data, data_size;
>> +
>> + data = qemu_get_be64(f);
>> + while (data != VFIO_MIG_FLAG_END_OF_STATE) {
>> +
>> + trace_vfio_load_state(vbasedev->name, data);
>> +
>> + switch (data) {
>> + case VFIO_MIG_FLAG_DEV_CONFIG_STATE:
>> + {
>> + ret = vfio_load_device_config_state(f, opaque);
>> + if (ret) {
>> + return ret;
>> + }
>> + break;
>> + }
>> + case VFIO_MIG_FLAG_DEV_SETUP_STATE:
>> + {
>> + data = qemu_get_be64(f);
>> + if (data == VFIO_MIG_FLAG_END_OF_STATE) {
>> + return ret;
>> + } else {
>> + error_report("%s: SETUP STATE: EOS not found 0x%"PRIx64,
>> + vbasedev->name, data);
>> + return -EINVAL;
>> + }
>> + break;
>> + }
>> + case VFIO_MIG_FLAG_DEV_DATA_STATE:
>> + {
>> + VFIORegion *region = &migration->region;
>> + uint64_t data_offset = 0, size;
>
> I think this function would benefit from splitting this off into a
> function handling DEV_DATA_STATE. It is quite hard to follow through
> all the checks and find out when we continue, and when we break off.
>
Each switch case has a break, we break off on success cases, where as we
return error if we encounter any case where (ret < 0)
> Some documentation about the markers would also be really helpful.
Sure adding it in patch 07, where these are defined.
> The logic seems to be:
> - DEV_CONFIG_STATE has config data and must be ended by END_OF_STATE
Right
> - DEV_SETUP_STATE has only END_OF_STATE, no data
Right now there is no data, but this is provision to add data if
required in future.
> - DEV_DATA_STATE has... data; if there's any END_OF_STATE, it's buried
> far down in the called functions
>
This is not correct, END_OF_STATE is after data. Moved data buffer
loading logic to function vfio_load_buffer(), so DEV_DATA_STATE looks
simplified as below. Hope this helps.
case VFIO_MIG_FLAG_DEV_DATA_STATE:
{
uint64_t data_size;
data_size = qemu_get_be64(f);
if (data_size == 0) {
break;
}
ret = vfio_load_buffer(f, vbasedev, data_size);
if (ret < 0) {
return ret;
}
break;
}
Also handling the case if data_size is greater than the data section of
migration region at destination in vfio_load_buffer()in my next version.
Thanks,
Kirti
>
>> +
>> + data_size = size = qemu_get_be64(f);
>> + if (data_size == 0) {
>> + break;
>> + }
>> +
>> + ret = vfio_mig_read(vbasedev, &data_offset, sizeof(data_offset),
>> + region->fd_offset +
>> + offsetof(struct vfio_device_migration_info,
>> + data_offset));
>> + if (ret < 0) {
>> + return ret;
>> + }
>> +
>> + trace_vfio_load_state_device_data(vbasedev->name, data_offset,
>> + data_size);
>> +
>> + while (size) {
>> + void *buf = NULL;
>> + uint64_t sec_size;
>> + bool buf_alloc = false;
>> +
>> + buf = get_data_section_size(region, data_offset, size,
>> + &sec_size);
>> +
>> + if (!buf) {
>> + buf = g_try_malloc(sec_size);
>> + if (!buf) {
>> + error_report("%s: Error allocating buffer ", __func__);
>> + return -ENOMEM;
>> + }
>> + buf_alloc = true;
>> + }
>> +
>> + qemu_get_buffer(f, buf, sec_size);
>> +
>> + if (buf_alloc) {
>> + ret = vfio_mig_write(vbasedev, buf, sec_size,
>> + region->fd_offset + data_offset);
>> + g_free(buf);
>> +
>> + if (ret < 0) {
>> + return ret;
>> + }
>> + }
>> + size -= sec_size;
>> + data_offset += sec_size;
>> + }
>> +
>> + ret = vfio_mig_write(vbasedev, &data_size, sizeof(data_size),
>> + region->fd_offset +
>> + offsetof(struct vfio_device_migration_info, data_size));
>> + if (ret < 0) {
>> + return ret;
>> + }
>> + break;
>> + }
>> +
>> + default:
>> + error_report("%s: Unknown tag 0x%"PRIx64, vbasedev->name, data);
>> + return -EINVAL;
>> + }
>> +
>> + data = qemu_get_be64(f);
>> + ret = qemu_file_get_error(f);
>> + if (ret) {
>> + 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,
>> + .load_setup = vfio_load_setup,
>> + .load_cleanup = vfio_load_cleanup,
>
> Unrelated to this patch: It's a bit odd that load_cleanup() (unlike
> save_cleanup()) has a return code (that seems unused).
>
>> + .load_state = vfio_load_state,
>> };
>>
>> /* ---------------------------------------------------------------------- */
>
next prev parent reply other threads:[~2020-10-18 20:49 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
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 [this message]
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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