From: Kirti Wankhede <kwankhede@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: cohuck@redhat.com, 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,
changpeng.liu@intel.com, eskultet@redhat.com, Ken.Xue@amd.com,
jonathan.davies@nutanix.com, pbonzini@redhat.com
Subject: Re: [PATCH QEMU v25 07/17] vfio: Register SaveVMHandlers for VFIO device
Date: Wed, 24 Jun 2020 00:51:06 +0530 [thread overview]
Message-ID: <542ced5e-0380-19b9-91d2-5f40c5857719@nvidia.com> (raw)
In-Reply-To: <20200622165024.5b2eb251@x1.home>
On 6/23/2020 4:20 AM, Alex Williamson wrote:
> On Sun, 21 Jun 2020 01:51:16 +0530
> 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 migration
>> 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 VFIO
>> device. During save-restore, VM is paused, _SAVING state is set for VFIO device.
>>
>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
>> Reviewed-by: Neo Jia <cjia@nvidia.com>
>> ---
>> hw/vfio/migration.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>> hw/vfio/trace-events | 2 ++
>> 2 files changed, 94 insertions(+)
>>
>> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
>> index e30bd8768701..133bb5b1b3b2 100644
>> --- a/hw/vfio/migration.c
>> +++ b/hw/vfio/migration.c
>> @@ -8,12 +8,15 @@
>> */
>>
>> #include "qemu/osdep.h"
>> +#include "qemu/main-loop.h"
>> +#include "qemu/cutils.h"
>> #include <linux/vfio.h>
>>
>> #include "sysemu/runstate.h"
>> #include "hw/vfio/vfio-common.h"
>> #include "cpu.h"
>> #include "migration/migration.h"
>> +#include "migration/vmstate.h"
>> #include "migration/qemu-file.h"
>> #include "migration/register.h"
>> #include "migration/blocker.h"
>> @@ -24,6 +27,17 @@
>> #include "pci.h"
>> #include "trace.h"
>>
>> +/*
>> + * Flags used as delimiter:
>> + * 0xffffffff => MSB 32-bit all 1s
>> + * 0xef10 => emulated (virtual) function IO
>> + * 0x0000 => 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 = vbasedev->migration;
>> @@ -126,6 +140,65 @@ static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask,
>> return 0;
>> }
>>
>> +/* ---------------------------------------------------------------------- */
>> +
>> +static int vfio_save_setup(QEMUFile *f, void *opaque)
>> +{
>> + VFIODevice *vbasedev = opaque;
>> + VFIOMigration *migration = vbasedev->migration;
>> + int ret;
>> +
>> + trace_vfio_save_setup(vbasedev->name);
>> +
>> + qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
>> +
>> + if (migration->region.mmaps) {
>> + qemu_mutex_lock_iothread();
>> + ret = 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.nr,
>> + strerror(-ret));
>> + return ret;
>
> OTOH to my previous comments, this shouldn't be fatal, right? mmaps
> are optional anyway so it should be sufficient to push an error report
> to explain why this might be slower than normal, but we can still
> proceed.
>
Right, defining region to be sparse mmap is optional.
migration->region.mmaps is set if vendor driver defines sparse mmapable
regions and VFIO_REGION_INFO_FLAG_MMAP flag is set. If this flag is set
then error on mmap() should be fatal.
If there is not mmapable region, then migration will proceed.
>> + }
>> + }
>> +
>> + ret = vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_MASK,
>> + VFIO_DEVICE_STATE_SAVING);
>> + if (ret) {
>> + error_report("%s: Failed to set state SAVING", vbasedev->name);
>> + return ret;
>> + }
>
> We seem to be lacking support in the callers for detecting if the
> device is in an error state. I'm not sure what our options are
> though, maybe only a hw_error().
>
Returning error here fails migration process. And if device is in error
state, any application running inside VM using this device would fail.
I think, there is no need to take any special action here by detecting
device error state.
>> +
>> + qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
>> +
>> + ret = qemu_file_get_error(f);
>> + if (ret) {
>> + return ret;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static void vfio_save_cleanup(void *opaque)
>> +{
>> + VFIODevice *vbasedev = opaque;
>> + VFIOMigration *migration = vbasedev->migration;
>> +
>> + if (migration->region.mmaps) {
>> + vfio_region_unmap(&migration->region);
>> + }
>> + trace_vfio_save_cleanup(vbasedev->name);
>> +}
>> +
>> +static SaveVMHandlers savevm_vfio_handlers = {
>> + .save_setup = vfio_save_setup,
>> + .save_cleanup = vfio_save_cleanup,
>> +};
>> +
>> +/* ---------------------------------------------------------------------- */
>> +
>> static void vfio_vmstate_change(void *opaque, int running, RunState state)
>> {
>> VFIODevice *vbasedev = opaque;
>> @@ -180,6 +253,7 @@ static int vfio_migration_init(VFIODevice *vbasedev,
>> struct vfio_region_info *info)
>> {
>> int ret;
>> + char id[256] = "";
>>
>> vbasedev->migration = g_new0(VFIOMigration, 1);
>>
>> @@ -192,6 +266,24 @@ static int vfio_migration_init(VFIODevice *vbasedev,
>> return ret;
>> }
>>
>> + if (vbasedev->ops->vfio_get_object) {
>
> Nit, vfio_migration_region_init() would have failed already if this were
> not available. Perhaps do the test once at the start of this function
> instead? Thanks,
>
Ok, will do that.
Thanks,
Kirti
> Alex
>
>> + Object *obj = vbasedev->ops->vfio_get_object(vbasedev);
>> +
>> + if (obj) {
>> + DeviceState *dev = DEVICE(obj);
>> + char *oid = vmstate_if_get_id(VMSTATE_IF(dev));
>> +
>> + if (oid) {
>> + pstrcpy(id, sizeof(id), oid);
>> + pstrcat(id, sizeof(id), "/");
>> + g_free(oid);
>> + }
>> + }
>> + }
>> + pstrcat(id, sizeof(id), "vfio");
>> +
>> + register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, &savevm_vfio_handlers,
>> + vbasedev);
>> vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change,
>> vbasedev);
>> vbasedev->migration_state.notify = vfio_migration_state_notifier;
>> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
>> index bd3d47b005cb..86c18def016e 100644
>> --- a/hw/vfio/trace-events
>> +++ b/hw/vfio/trace-events
>> @@ -149,3 +149,5 @@ vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d"
>> vfio_migration_set_state(const char *name, uint32_t state) " (%s) state %d"
>> vfio_vmstate_change(const char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d"
>> vfio_migration_state_notifier(const char *name, const char *state) " (%s) state %s"
>> +vfio_save_setup(const char *name) " (%s)"
>> +vfio_save_cleanup(const char *name) " (%s)"
>
next prev parent reply other threads:[~2020-06-23 19:22 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-20 20:21 [PATCH QEMU v25 00/17] Add migration support for VFIO devices Kirti Wankhede
2020-06-20 20:21 ` [PATCH QEMU v25 01/17] vfio: Add function to unmap VFIO region Kirti Wankhede
2020-06-20 20:21 ` [PATCH QEMU v25 02/17] vfio: Add vfio_get_object callback to VFIODeviceOps Kirti Wankhede
2020-06-20 20:21 ` [PATCH QEMU v25 03/17] vfio: Add save and load functions for VFIO PCI devices Kirti Wankhede
2020-06-22 20:28 ` Alex Williamson
2020-06-24 14:29 ` Kirti Wankhede
2020-06-24 19:49 ` Alex Williamson
2020-06-26 12:16 ` Dr. David Alan Gilbert
2020-06-26 22:44 ` Alex Williamson
2020-06-29 9:59 ` Dr. David Alan Gilbert
2020-06-20 20:21 ` [PATCH QEMU v25 04/17] vfio: Add migration region initialization and finalize function Kirti Wankhede
2020-06-23 7:54 ` Cornelia Huck
2020-06-20 20:21 ` [PATCH QEMU v25 05/17] vfio: Add VM state change handler to know state of VM Kirti Wankhede
2020-06-22 22:50 ` Alex Williamson
2020-06-23 18:55 ` Kirti Wankhede
2020-06-26 14:51 ` Dr. David Alan Gilbert
2020-06-23 8:07 ` Cornelia Huck
2020-06-20 20:21 ` [PATCH QEMU v25 06/17] vfio: Add migration state change notifier Kirti Wankhede
2020-06-23 8:10 ` Cornelia Huck
2020-06-20 20:21 ` [PATCH QEMU v25 07/17] vfio: Register SaveVMHandlers for VFIO device Kirti Wankhede
2020-06-22 22:50 ` Alex Williamson
2020-06-23 19:21 ` Kirti Wankhede [this message]
2020-06-23 19:50 ` Alex Williamson
2020-06-26 14:22 ` Dr. David Alan Gilbert
2020-06-26 14:31 ` Dr. David Alan Gilbert
2020-06-20 20:21 ` [PATCH QEMU v25 08/17] vfio: Add save state functions to SaveVMHandlers Kirti Wankhede
2020-06-22 22:50 ` Alex Williamson
2020-06-23 20:34 ` Kirti Wankhede
2020-06-23 20:40 ` Alex Williamson
2020-06-20 20:21 ` [PATCH QEMU v25 09/17] vfio: Add load " Kirti Wankhede
2020-06-24 18:54 ` Alex Williamson
2020-06-25 14:16 ` Kirti Wankhede
2020-06-25 14:57 ` Alex Williamson
2020-06-26 14:54 ` Dr. David Alan Gilbert
2020-06-20 20:21 ` [PATCH QEMU v25 10/17] memory: Set DIRTY_MEMORY_MIGRATION when IOMMU is enabled Kirti Wankhede
2020-06-20 20:21 ` [PATCH QEMU v25 11/17] vfio: Get migration capability flags for container Kirti Wankhede
2020-06-24 8:43 ` Cornelia Huck
2020-06-24 18:55 ` Alex Williamson
2020-06-25 14:09 ` Kirti Wankhede
2020-06-25 14:56 ` Alex Williamson
2020-06-20 20:21 ` [PATCH QEMU v25 12/17] vfio: Add function to start and stop dirty pages tracking Kirti Wankhede
2020-06-23 10:32 ` Cornelia Huck
2020-06-23 11:01 ` Dr. David Alan Gilbert
2020-06-23 11:06 ` Cornelia Huck
2020-06-24 18:55 ` Alex Williamson
2020-06-20 20:21 ` [PATCH QEMU v25 13/17] vfio: create mapped iova list when vIOMMU is enabled Kirti Wankhede
2020-06-24 18:55 ` Alex Williamson
2020-06-25 14:34 ` Kirti Wankhede
2020-06-25 17:40 ` Alex Williamson
2020-06-26 14:43 ` Peter Xu
2020-06-20 20:21 ` [PATCH QEMU v25 14/17] vfio: Add vfio_listener_log_sync to mark dirty pages Kirti Wankhede
2020-06-24 18:55 ` Alex Williamson
2020-06-25 14:43 ` Kirti Wankhede
2020-06-25 17:57 ` Alex Williamson
2020-06-20 20:21 ` [PATCH QEMU v25 15/17] vfio: Add ioctl to get dirty pages bitmap during dma unmap Kirti Wankhede
2020-06-23 8:25 ` Cornelia Huck
2020-06-24 18:56 ` Alex Williamson
2020-06-25 15:01 ` Kirti Wankhede
2020-06-25 19:18 ` Alex Williamson
2020-06-26 14:15 ` Dr. David Alan Gilbert
2020-06-20 20:21 ` [PATCH QEMU v25 16/17] vfio: Make vfio-pci device migration capable Kirti Wankhede
2020-06-22 16:51 ` Cornelia Huck
2020-06-20 20:21 ` [PATCH QEMU v25 17/17] qapi: Add VFIO devices migration stats in Migration stats Kirti Wankhede
2020-06-23 7:21 ` Markus Armbruster
2020-06-23 21:16 ` Kirti Wankhede
2020-06-25 5:51 ` Markus Armbruster
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