qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 3/5] Add migration functions for VFIO devices


From: Zhao Yan
Subject: Re: [Qemu-devel] [PATCH 3/5] Add migration functions for VFIO devices
Date: Fri, 23 Nov 2018 00:29:58 -0500
User-agent: Mutt/1.9.4 (2018-02-28)

On Fri, Nov 23, 2018 at 02:51:39AM +0530, Kirti Wankhede wrote:
> 
> 
> On 11/21/2018 1:09 PM, Zhao, Yan Y wrote:
> > 
> > 
> >> -----Original Message-----
> >> From: Qemu-devel [mailto:qemu-devel-
> >> address@hidden On Behalf Of Kirti Wankhede
> >> Sent: Wednesday, November 21, 2018 4:40 AM
> >> To: address@hidden; address@hidden
> >> Cc: address@hidden; Tian, Kevin <address@hidden>; Liu, Yi L
> >> <address@hidden>; address@hidden; Yang, Ziye <address@hidden>;
> >> address@hidden; address@hidden; address@hidden;
> >> address@hidden; Wang, Zhi A <address@hidden>;
> >> address@hidden; address@hidden; address@hidden; Kirti Wankhede
> >> <address@hidden>; address@hidden; address@hidden;
> >> address@hidden; Liu, Changpeng <address@hidden>;
> >> address@hidden
> >> Subject: [Qemu-devel] [PATCH 3/5] Add migration functions for VFIO devices
> >>
> >> - Migration function are implemented for VFIO_DEVICE_TYPE_PCI device.
> >> - Added SaveVMHandlers and implemented all basic functions required for 
> >> live
> >>   migration.
> >> - Added VM state change handler to know running or stopped state of VM.
> >> - Added migration state change notifier to get notification on migration 
> >> state
> >>   change. This state is translated to VFIO device state and conveyed to 
> >> vendor
> >>   driver.
> >> - VFIO device supportd migration or not is decided based of migration 
> >> region
> >>   query. If migration region query is successful then migration is 
> >> supported
> >>   else migration is blocked.
> >> - Structure vfio_device_migration_info is mapped at 0th offset of migration
> >>   region and should always trapped by VFIO device's driver. Added both 
> >> type of
> >>   access support, trapped or mmapped, for data section of the region.
> >> - To save device state, read data offset and size using structure
> >>   vfio_device_migration_info.data, accordingly copy data from the region.
> >> - To restore device state, write data offset and size in the structure and 
> >> write
> >>   data in the region.
> >> - To get dirty page bitmap, write start address and pfn count then read 
> >> count of
> >>   pfns copied and accordingly read those from the rest of the region or 
> >> mmaped
> >>   part of the region. This copy is iterated till page bitmap for all 
> >> requested
> >>   pfns are copied.
> >>
> >> Signed-off-by: Kirti Wankhede <address@hidden>
> >> Reviewed-by: Neo Jia <address@hidden>
> >> ---
> >>  hw/vfio/Makefile.objs         |   2 +-
> >>  hw/vfio/migration.c           | 729
> >> ++++++++++++++++++++++++++++++++++++++++++
> >>  include/hw/vfio/vfio-common.h |  23 ++
> >>  3 files changed, 753 insertions(+), 1 deletion(-)  create mode 100644
> >> hw/vfio/migration.c
> >>
> >> diff --git a/hw/vfio/Makefile.objs b/hw/vfio/Makefile.objs index
> >> a2e7a0a7cf02..2cf2ba1440f2 100644
> >> --- a/hw/vfio/Makefile.objs
> >> +++ b/hw/vfio/Makefile.objs
> >> @@ -1,5 +1,5 @@
> >>  ifeq ($(CONFIG_LINUX), y)
> >> -obj-$(CONFIG_SOFTMMU) += common.o
> >> +obj-$(CONFIG_SOFTMMU) += common.o migration.o
> >>  obj-$(CONFIG_PCI) += pci.o pci-quirks.o display.o
> >>  obj-$(CONFIG_VFIO_CCW) += ccw.o
> >>  obj-$(CONFIG_SOFTMMU) += platform.o
> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c new file mode 100644
> >> index 000000000000..717fb63e4f43
> >> --- /dev/null
> >> +++ b/hw/vfio/migration.c
> >> @@ -0,0 +1,729 @@
> >> +/*
> >> + * Migration support for VFIO devices
> >> + *
> >> + * Copyright NVIDIA, Inc. 2018
> >> + *
> >> + * This work is licensed under the terms of the GNU GPL, version 2. See
> >> + * the COPYING file in the top-level directory.
> >> + */
> >> +
> >> +#include "qemu/osdep.h"
> >> +#include <linux/vfio.h>
> >> +
> >> +#include "hw/vfio/vfio-common.h"
> >> +#include "cpu.h"
> >> +#include "migration/migration.h"
> >> +#include "migration/qemu-file.h"
> >> +#include "migration/register.h"
> >> +#include "migration/blocker.h"
> >> +#include "migration/misc.h"
> >> +#include "qapi/error.h"
> >> +#include "exec/ramlist.h"
> >> +#include "exec/ram_addr.h"
> >> +#include "pci.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)
> >> +
> >> +static void vfio_migration_region_exit(VFIODevice *vbasedev) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +
> >> +    if (!migration) {
> >> +        return;
> >> +    }
> >> +
> >> +    if (migration->region.buffer.size) {
> >> +        vfio_region_exit(&migration->region.buffer);
> >> +        vfio_region_finalize(&migration->region.buffer);
> >> +    }
> >> +}
> >> +
> >> +static int vfio_migration_region_init(VFIODevice *vbasedev) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    Object *obj = NULL;
> >> +    int ret = -EINVAL;
> >> +
> >> +    if (!migration) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    /* Migration support added for PCI device only */
> >> +    if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
> >> +        obj = vfio_pci_get_object(vbasedev);
> >> +    }
> >> +
> >> +    if (!obj) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    ret = vfio_region_setup(obj, vbasedev, &migration->region.buffer,
> >> +                            migration->region.index, "migration");
> >> +    if (ret) {
> >> +        error_report("Failed to setup VFIO migration region %d: %s",
> >> +                      migration->region.index, strerror(-ret));
> >> +        goto err;
> >> +    }
> >> +
> >> +    if (!migration->region.buffer.size) {
> >> +        ret = -EINVAL;
> >> +        error_report("Invalid region size of VFIO migration region %d: 
> >> %s",
> >> +                     migration->region.index, strerror(-ret));
> >> +        goto err;
> >> +    }
> >> +
> >> +    if (migration->region.buffer.mmaps) {
> >> +        ret = vfio_region_mmap(&migration->region.buffer);
> >> +        if (ret) {
> >> +            error_report("Failed to mmap VFIO migration region %d: %s",
> >> +                         migration->region.index, strerror(-ret));
> >> +            goto err;
> >> +        }
> >> +    }
> >> +
> >> +    return 0;
> >> +
> >> +err:
> >> +    vfio_migration_region_exit(vbasedev);
> >> +    return ret;
> >> +}
> >> +
> >> +static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t
> >> +state) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    VFIORegion *region = &migration->region.buffer;
> >> +    int ret = 0;
> >> +
> >> +    if (vbasedev->device_state == state) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    ret = pwrite(vbasedev->fd, &state, sizeof(state),
> >> +                 region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                              device_state));
> >> +    if (ret < 0) {
> >> +        error_report("Failed to set migration state %d %s",
> >> +                     ret, strerror(errno));
> >> +        return ret;
> >> +    }
> >> +
> >> +    vbasedev->device_state = state;
> >> +    return ret;
> >> +}
> >> +
> >> +void vfio_get_dirty_page_list(VFIODevice *vbasedev,
> >> +                              uint64_t start_addr,
> >> +                              uint64_t pfn_count) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    VFIORegion *region = &migration->region.buffer;
> >> +    struct vfio_device_migration_info migration_info;
> >> +    uint64_t count = 0;
> >> +    int ret;
> >> +
> >> +    migration_info.dirty_pfns.start_addr = start_addr;
> >> +    migration_info.dirty_pfns.total = pfn_count;
> >> +
> >> +    ret = pwrite(vbasedev->fd, &migration_info.dirty_pfns,
> >> +                 sizeof(migration_info.dirty_pfns),
> >> +                 region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                              dirty_pfns));
> >> +    if (ret < 0) {
> >> +        error_report("Failed to set dirty pages start address %d %s",
> >> +                ret, strerror(errno));
> >> +        return;
> >> +    }
> >> +
> >> +    do {
> >> +        /* Read dirty_pfns.copied */
> >> +        ret = pread(vbasedev->fd, &migration_info.dirty_pfns,
> >> +                sizeof(migration_info.dirty_pfns),
> >> +                region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                             dirty_pfns));
> >> +        if (ret < 0) {
> >> +            error_report("Failed to get dirty pages bitmap count %d %s",
> >> +                    ret, strerror(errno));
> >> +            return;
> >> +        }
> >> +
> >> +        if (migration_info.dirty_pfns.copied) {
> >> +            uint64_t bitmap_size;
> >> +            void *buf = NULL;
> >> +            bool buffer_mmaped = false;
> >> +
> >> +            bitmap_size = 
> >> (BITS_TO_LONGS(migration_info.dirty_pfns.copied) + 1)
> >> +                           * sizeof(unsigned long);
> >> +
> >> +            if (region->mmaps) {
> >> +                int i;
> >> +
> >> +                for (i = 0; i < region->nr_mmaps; i++) {
> >> +                    if (region->mmaps[i].size >= bitmap_size) {
> >> +                        buf = region->mmaps[i].mmap;
> >> +                        buffer_mmaped = true;
> >> +                        break;
> >> +                    }
> >> +                }
> >> +            }
> > What if mmapped data area is in front of mmaped dirty bit area?
> > Maybe you need to record dirty bit region's index as what does for data 
> > region.
> >
> 
> No, data section is not different than dirty bit area.
> Migration region is like:
>  ----------------------------------------------------------------------
> |vfio_device_migration_info|    data section                        | 
> |                          |     ///////////////////////////////////  |
>  ----------------------------------------------------------------------
>  ^                             ^                                 ^
>  offset 0-trapped part         data.offset                     data.size
> 
> Same data section is used to copy vendor driver data during save and
> during dirty page bitmap query.
Right, I know data section is the same as dirty bit section, as they are
both mmaped. but it's not right to assume dirty bit section to be the first
one to found from region->mmaps[i].mmap.

> 
> >> +
> >> +            if (!buffer_mmaped) {
> >> +                buf = g_malloc0(bitmap_size);
> >> +
> >> +                ret = pread(vbasedev->fd, buf, bitmap_size,
> >> +                            region->fd_offset + sizeof(migration_info) + 
> >> 1);
Ditto. it's not right to assume dirty bit section starting right after
migration_info.

> >> +                if (ret != bitmap_size) {
> >> +                    error_report("Failed to get migration data %d", ret);
> >> +                    g_free(buf);
> >> +                    return;
> >> +                }
> >> +            }
> >> +
> >> +            cpu_physical_memory_set_dirty_lebitmap((unsigned long *)buf,
> >> +                                        start_addr + (count * 
> >> TARGET_PAGE_SIZE),
> >> +                                        migration_info.dirty_pfns.copied);
> >> +            count +=  migration_info.dirty_pfns.copied;
> >> +
> >> +            if (!buffer_mmaped) {
> >> +                g_free(buf);
> >> +            }
> >> +        }
> >> +    } while (count < migration_info.dirty_pfns.total); }
> >> +
> >> +static int vfio_save_device_config_state(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_CONFIG_STATE);
> >> +
> >> +    if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
> >> +        vfio_pci_save_config(vbasedev, f);
> >> +    }
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> >> +
> >> +    return qemu_file_get_error(f);
> >> +}
> >> +
> >> +static int vfio_load_device_config_state(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +
> >> +    if (vbasedev->type == VFIO_DEVICE_TYPE_PCI) {
> >> +        vfio_pci_load_config(vbasedev, f);
> >> +    }
> >> +
> >> +    if (qemu_get_be64(f) != VFIO_MIG_FLAG_END_OF_STATE) {
> >> +        error_report("Wrong end of block while loading device config 
> >> space");
> >> +        return -EINVAL;
> >> +    }
> >> +
> >> +    return qemu_file_get_error(f);
> >> +}
> >> +
> > What's the purpose to add a tailing VFIO_MIG_FLAG_END_OF_STATE for each 
> > section? 
> > For compatibility check?
> > Maybe a version id or magic in struct vfio_device_migration_info is more 
> > appropriate?
> > 
> 
> No, this is to identify the section end during resume, see
> vfio_load_state().
> 
as long as save/load are of the same version, it's not necessary to add a
taling ending mark.

> > 
> >> +/*
> >> +----------------------------------------------------------------------
> >> +*/
> >> +
> >> +static bool vfio_is_active_iterate(void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +
> >> +    if (vbasedev->vm_running && vbasedev->migration &&
> >> +        (vbasedev->migration->pending_precopy_only != 0))
> >> +        return true;
> >> +
> >> +    if (!vbasedev->vm_running && vbasedev->migration &&
> >> +        (vbasedev->migration->pending_postcopy != 0))
> >> +        return true;
> >> +
> >> +    return false;
> >> +}
> >> +
> >> +static int vfio_save_setup(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    int ret;
> >> +
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_DEV_SETUP_STATE);
> >> +
> >> +    qemu_mutex_lock_iothread();
> >> +    ret = vfio_migration_region_init(vbasedev);
> >> +    qemu_mutex_unlock_iothread();
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> >> +
> >> +    ret = qemu_file_get_error(f);
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    return 0;
> >> +}
> >> +
> >> +static int vfio_save_buffer(QEMUFile *f, VFIODevice *vbasedev) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    VFIORegion *region = &migration->region.buffer;
> >> +    struct vfio_device_migration_info migration_info;
> >> +    int ret;
> >> +
> >> +    ret = pread(vbasedev->fd, &migration_info.data,
> >> +                sizeof(migration_info.data),
> >> +                region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                             data));
> >> +    if (ret != sizeof(migration_info.data)) {
> >> +        error_report("Failed to get migration buffer information %d",
> >> +                     ret);
> >> +        return -EINVAL;
> >> +    }
> >> +
> >> +    if (migration_info.data.size) {
> >> +        void *buf = NULL;
> >> +        bool buffer_mmaped = false;
> >> +
> >> +        if (region->mmaps) {
> >> +            int i;
> >> +
> >> +            for (i = 0; i < region->nr_mmaps; i++) {
> >> +                if (region->mmaps[i].offset == 
> >> migration_info.data.offset) {
> >> +                    buf = region->mmaps[i].mmap;
> >> +                    buffer_mmaped = true;
> >> +                    break;
> >> +                }
> >> +            }
> >> +        }
> >> +
> >> +        if (!buffer_mmaped) {
> >> +            buf = g_malloc0(migration_info.data.size);
> >> +            ret = pread(vbasedev->fd, buf, migration_info.data.size,
> >> +                        region->fd_offset + migration_info.data.offset);
> >> +            if (ret != migration_info.data.size) {
> >> +                error_report("Failed to get migration data %d", ret);
> >> +                return -EINVAL;
> >> +            }
> >> +        }
> >> +
> >> +        qemu_put_be64(f, migration_info.data.size);
> >> +        qemu_put_buffer(f, buf, migration_info.data.size);
> >> +
> >> +        if (!buffer_mmaped) {
> >> +            g_free(buf);
> >> +        }
> >> +
> >> +    } else {
> >> +        qemu_put_be64(f, migration_info.data.size);
> >> +    }
> >> +
> >> +    ret = qemu_file_get_error(f);
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    return migration_info.data.size;
> >> +}
> >> +
> >> +static int vfio_save_iterate(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    int ret;
> >> +
> >> +    ret = vfio_save_buffer(f, vbasedev);
> >> +    if (ret < 0) {
> >> +        error_report("vfio_save_buffer failed %s",
> >> +                     strerror(errno));
> >> +        return ret;
> >> +    }
> >> +
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> >> +
> >> +    ret = qemu_file_get_error(f);
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    return ret;
> >> +}
> >> +
> >> +static void vfio_update_pending(VFIODevice *vbasedev, uint64_t
> >> +threshold_size) {
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    VFIORegion *region = &migration->region.buffer;
> >> +    struct vfio_device_migration_info migration_info;
> >> +    int ret;
> >> +
> >> +    ret = pwrite(vbasedev->fd, &threshold_size, sizeof(threshold_size),
> >> +                 region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                              pending.threshold_size));
> >> +    if (ret < 0) {
> >> +        error_report("Failed to set threshold size %d %s",
> >> +                     ret, strerror(errno));
> >> +        return;
> >> +    }
> >> +
> >> +    ret = pread(vbasedev->fd, &migration_info.pending,
> >> +                sizeof(migration_info.pending),
> >> +                region->fd_offset + offsetof(struct 
> >> vfio_device_migration_info,
> >> +                                             pending));
> >> +    if (ret != sizeof(migration_info.pending)) {
> >> +        error_report("Failed to get pending bytes %d", ret);
> >> +        return;
> >> +    }
> >> +
> >> +    migration->pending_precopy_only = migration_info.pending.precopy_only;
> >> +    migration->pending_compatible = migration_info.pending.compatible;
> >> +    migration->pending_postcopy = migration_info.pending.postcopy_only;
> >> +
> >> +    return;
> >> +}
> >> +
> >> +static void vfio_save_pending(QEMUFile *f, void *opaque,
> >> +                              uint64_t threshold_size,
> >> +                              uint64_t *res_precopy_only,
> >> +                              uint64_t *res_compatible,
> >> +                              uint64_t *res_postcopy_only) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +
> >> +    vfio_update_pending(vbasedev, threshold_size);
> >> +
> >> +    *res_precopy_only += migration->pending_precopy_only;
> >> +    *res_compatible += migration->pending_compatible;
> >> +    *res_postcopy_only += migration->pending_postcopy; }
> >> +
> >> +static int vfio_save_complete_precopy(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    VFIOMigration *migration = vbasedev->migration;
> >> +    MigrationState *ms = migrate_get_current();
> >> +    int ret;
> >> +
> >> +    if (vbasedev->vm_running) {
> >> +        vbasedev->vm_running = 0;
> >> +    }
> >> +
> >> +    ret = vfio_migration_set_state(vbasedev,
> >> +                                   VFIO_DEVICE_STATE_MIGRATION_STOPNCOPY);
> >> +    if (ret) {
> >> +        error_report("Failed to set state STOPNCOPY_ACTIVE");
> >> +        return ret;
> >> +    }
> >> +
> >> +    ret = vfio_save_device_config_state(f, opaque);
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    do {
> >> +        vfio_update_pending(vbasedev, ms->threshold_size);
> >> +
> >> +        if (vfio_is_active_iterate(opaque)) {
> >> +            ret = vfio_save_buffer(f, vbasedev);
> >> +            if (ret < 0) {
> >> +                error_report("Failed to save buffer");
> >> +                break;
> >> +            } else if (ret == 0) {
> >> +                break;
> >> +            }
> >> +        }
> >> +    } while ((migration->pending_compatible +
> >> + migration->pending_postcopy) > 0);
> >> +
> > 
> > if migration->pending_postcopy is not 0, vfio_save_complete_precopy() 
> > cannot finish? Is that true?
> > But vfio_save_complete_precopy() does not need to copy post copy data.
> > 
> >
> 
> This is stop and copy phase, that is pre-copy phase ended and vCPUs are
> stopped. So all data for device should be copied in this callback.
postcopy data is not requried to be copied in stop-and-copy phase.

> 
> > 
> >> +    qemu_put_be64(f, VFIO_MIG_FLAG_END_OF_STATE);
> >> +
> >> +    ret = qemu_file_get_error(f);
> >> +    if (ret) {
> >> +        return ret;
> >> +    }
> >> +
> >> +    ret = vfio_migration_set_state(vbasedev,
> >> +                                   
> >> VFIO_DEVICE_STATE_MIGRATION_SAVE_COMPLETED);
> >> +    if (ret) {
> >> +        error_report("Failed to set state SAVE_COMPLETED");
> >> +        return ret;
> >> +    }
> >> +    return ret;
> >> +}
> >> +
> >> +static void vfio_save_cleanup(void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +
> >> +    vfio_migration_region_exit(vbasedev);
> >> +}
> >> +
> >> +static int vfio_load_state(QEMUFile *f, void *opaque, int version_id) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    int ret;
> >> +    uint64_t data;
> >> +
> > Need to use version_id to check source and target version.
> > 
> 
> Good point. I'll add that.
> 
> >> +    data = qemu_get_be64(f);
> >> +    while (data != VFIO_MIG_FLAG_END_OF_STATE) {
> >> +        if (data == VFIO_MIG_FLAG_DEV_CONFIG_STATE) {
> >> +            ret = vfio_load_device_config_state(f, opaque);
> >> +            if (ret) {
> >> +                return ret;
> >> +            }
> >> +        } else if (data == VFIO_MIG_FLAG_DEV_SETUP_STATE) {
> >> +            data = qemu_get_be64(f);
> >> +            if (data == VFIO_MIG_FLAG_END_OF_STATE) {
> >> +                return 0;
> >> +            } else {
> >> +                error_report("SETUP STATE: EOS not found 0x%lx", data);
> >> +                return -EINVAL;
> >> +            }
> >> +        } else if (data != 0) {
> >> +            VFIOMigration *migration = vbasedev->migration;
> >> +            VFIORegion *region = &migration->region.buffer;
> >> +            struct vfio_device_migration_info migration_info;
> >> +            void *buf = NULL;
> >> +            bool buffer_mmaped = false;
> >> +
> >> +            migration_info.data.size = data;
> >> +
> >> +            if (region->mmaps) {
> >> +                int i;
> >> +
> >> +                for (i = 0; i < region->nr_mmaps; i++) {
> >> +                    if (region->mmaps[i].mmap &&
> >> +                        (region->mmaps[i].size >= data)) {
> >> +                        buf = region->mmaps[i].mmap;
> >> +                        migration_info.data.offset = 
> >> region->mmaps[i].offset;
> >> +                        buffer_mmaped = true;
> >> +                        break;
> >> +                    }
> >> +                }
> >> +            }
> >> +
> >> +            if (!buffer_mmaped) {
> >> +                buf = g_malloc0(migration_info.data.size);
> >> +                migration_info.data.offset = sizeof(migration_info) + 1;
> >> +            }
> >> +
> >> +            qemu_get_buffer(f, buf, data);
> >> +
> >> +            ret = pwrite(vbasedev->fd, &migration_info.data,
> >> +                         sizeof(migration_info.data),
> >> +                         region->fd_offset +
> >> +                         offsetof(struct vfio_device_migration_info, 
> >> data));
> >> +            if (ret != sizeof(migration_info.data)) {
> >> +                error_report("Failed to set migration buffer information 
> >> %d",
> >> +                        ret);
> >> +                return -EINVAL;
> >> +            }
> >> +
> >> +            if (!buffer_mmaped) {
> >> +                ret = pwrite(vbasedev->fd, buf, migration_info.data.size,
> >> +                             region->fd_offset + 
> >> migration_info.data.offset);
> >> +                g_free(buf);
> >> +
> >> +                if (ret != migration_info.data.size) {
> >> +                    error_report("Failed to set migration buffer %d", 
> >> ret);
> >> +                    return -EINVAL;
> >> +                }
> >> +            }
> >> +        }
> >> +
> >> +        ret = qemu_file_get_error(f);
> >> +        if (ret) {
> >> +            return ret;
> >> +        }
> >> +        data = qemu_get_be64(f);
> >> +    }
> >> +
> >> +    return 0;
> >> +}
> >> +
> >> +static int vfio_load_setup(QEMUFile *f, void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    int ret;
> >> +
> >> +    ret = vfio_migration_set_state(vbasedev,
> >> +                                    VFIO_DEVICE_STATE_MIGRATION_RESUME);
> >> +    if (ret) {
> >> +        error_report("Failed to set state RESUME");
> >> +    }
> >> +
> >> +    ret = vfio_migration_region_init(vbasedev);
> >> +    if (ret) {
> >> +        error_report("Failed to initialise migration region");
> >> +        return ret;
> >> +    }
> >> +
> >> +    return 0;
> >> +}
> >> +
> > Why vfio_migration_set_state() is in front of  vfio_migration_region_init()?
> > So VFIO_DEVICE_STATE_MIGRATION_RESUME is really useful? :)
> > 
> > 
> 
> Yes, how will kernel driver know that resume has started?
> 
> 
My point is that the migration region is setup in
vfio_migration_region_init(), while vfio_migration_set_state() depends on
the migration region to pass commands into the vendor driver.
so, before vfio_migration_region_init() is called, the calling of
vfio_migration_set_state() cannot succeed.


> >> +static int vfio_load_cleanup(void *opaque) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +    int ret = 0;
> >> +
> >> +    ret = vfio_migration_set_state(vbasedev,
> >> +                                 
> >> VFIO_DEVICE_STATE_MIGRATION_RESUME_COMPLETED);
> >> +    if (ret) {
> >> +        error_report("Failed to set state RESUME_COMPLETED");
> >> +    }
> >> +
> >> +    vfio_migration_region_exit(vbasedev);
> >> +    return ret;
> >> +}
> >> +
> >> +static SaveVMHandlers savevm_vfio_handlers = {
> >> +    .save_setup = vfio_save_setup,
> >> +    .save_live_iterate = vfio_save_iterate,
> >> +    .save_live_complete_precopy = vfio_save_complete_precopy,
> >> +    .save_live_pending = vfio_save_pending,
> >> +    .save_cleanup = vfio_save_cleanup,
> >> +    .load_state = vfio_load_state,
> >> +    .load_setup = vfio_load_setup,
> >> +    .load_cleanup = vfio_load_cleanup,
> >> +    .is_active_iterate = vfio_is_active_iterate, };
> >> +
> >> +static void vfio_vmstate_change(void *opaque, int running, RunState
> >> +state) {
> >> +    VFIODevice *vbasedev = opaque;
> >> +
> >> +    if ((vbasedev->vm_running != running) && running) {
> >> +        int ret;
> >> +
> >> +        ret = vfio_migration_set_state(vbasedev, 
> >> VFIO_DEVICE_STATE_RUNNING);
> >> +        if (ret) {
> >> +            error_report("Failed to set state RUNNING");
> >> +        }
> >> +    }
> >> +
> >> +    vbasedev->vm_running = running;
> >> +}
> >> +
> > vfio_vmstate_change() is registered at initialization, so for source vm 
> > vfio_migration_set_state(vbasedev, VFIO_DEVICE_STATE_RUNNING) will be 
> > called on vm start.
> > but vfio_migration_region_init() is called in save_setup() when migration 
> > starts,
> > as a result,  "vfio_migration_set_state(vbasedev, 
> > VFIO_DEVICE_STATE_RUNNING)" should not function here for source vm.
> > So, again, is this state really used? :)
> > 
> > 
> 
> vfio_vmstate_change() is not only called at VM start, this also gets
> called after resume is done. Kernel driver need to know after resume
> that vCPUs are running.
> 
so at the source vm side, on vm start, vfio_vmstate_change() and
vfio_migration_set_state(VFIO_DEVICE_STATE_RUNNING) are called.
However, at that stage, the vfio_migration_set_state() cannot succeed,
because migration regions are not setup at that stage. Migration regions
are setup in save_setup() when migration starts.



> Thanks,
> Kirti
> 
> >> +static void vfio_migration_state_notifier(Notifier *notifier, void
> >> +*data) {
> >> +    MigrationState *s = data;
> >> +    VFIODevice *vbasedev = container_of(notifier, VFIODevice, 
> >> migration_state);
> >> +    int ret;
> >> +
> >> +    switch (s->state) {
> >> +    case MIGRATION_STATUS_SETUP:
> >> +        ret = vfio_migration_set_state(vbasedev,
> >> +                                       VFIO_DEVICE_STATE_MIGRATION_SETUP);
> >> +        if (ret) {
> >> +            error_report("Failed to set state SETUP");
> >> +        }
> >> +        return;
> >> +
> >> +    case MIGRATION_STATUS_ACTIVE:
> >> +        if (vbasedev->device_state == VFIO_DEVICE_STATE_MIGRATION_SETUP) {
> >> +            if (vbasedev->vm_running) {
> >> +                ret = vfio_migration_set_state(vbasedev,
> >> +                                          
> >> VFIO_DEVICE_STATE_MIGRATION_PRECOPY);
> >> +                if (ret) {
> >> +                    error_report("Failed to set state PRECOPY_ACTIVE");
> >> +                }
> >> +            } else {
> >> +                ret = vfio_migration_set_state(vbasedev,
> >> +                                        
> >> VFIO_DEVICE_STATE_MIGRATION_STOPNCOPY);
> >> +                if (ret) {
> >> +                    error_report("Failed to set state STOPNCOPY_ACTIVE");
> >> +                }
> >> +            }
> >> +        } else {
> >> +            ret = vfio_migration_set_state(vbasedev,
> >> +                                           
> >> VFIO_DEVICE_STATE_MIGRATION_RESUME);
> >> +            if (ret) {
> >> +                error_report("Failed to set state RESUME");
> >> +            }
> >> +        }
> >> +        return;
> >> +
> >> +    case MIGRATION_STATUS_CANCELLING:
> >> +    case MIGRATION_STATUS_CANCELLED:
> >> +        ret = vfio_migration_set_state(vbasedev,
> >> +                                       
> >> VFIO_DEVICE_STATE_MIGRATION_CANCELLED);
> >> +        if (ret) {
> >> +            error_report("Failed to set state CANCELLED");
> >> +        }
> >> +        return;
> >> +
> >> +    case MIGRATION_STATUS_FAILED:
> >> +        ret = vfio_migration_set_state(vbasedev,
> >> +                                       
> >> VFIO_DEVICE_STATE_MIGRATION_FAILED);
> >> +        if (ret) {
> >> +            error_report("Failed to set state FAILED");
> >> +        }
> >> +        return;
> >> +    }
> >> +}
> >> +
> >> +static int vfio_migration_init(VFIODevice *vbasedev,
> >> +                               struct vfio_region_info *info) {
> >> +    vbasedev->migration = g_new0(VFIOMigration, 1);
> >> +    vbasedev->migration->region.index = info->index;
> >> +
> >> +    register_savevm_live(NULL, "vfio", -1, 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;
> >> +    add_migration_state_change_notifier(&vbasedev->migration_state);
> >> +
> >> +    return 0;
> >> +}
> >> +
> >> +
> >> +/*
> >> +----------------------------------------------------------------------
> >> +*/
> >> +
> >> +int vfio_migration_probe(VFIODevice *vbasedev, Error **errp) {
> >> +    struct vfio_region_info *info;
> >> +    int ret;
> >> +
> >> +    ret = vfio_get_dev_region_info(vbasedev, VFIO_REGION_TYPE_MIGRATION,
> >> +                                   VFIO_REGION_SUBTYPE_MIGRATION, &info);
> >> +    if (ret) {
> >> +        Error *local_err = NULL;
> >> +
> >> +        error_setg(&vbasedev->migration_blocker,
> >> +                   "VFIO device doesn't support migration");
> >> +        ret = migrate_add_blocker(vbasedev->migration_blocker, 
> >> &local_err);
> >> +        if (local_err) {
> >> +            error_propagate(errp, local_err);
> >> +            error_free(vbasedev->migration_blocker);
> >> +            return ret;
> >> +        }
> >> +    } else {
> >> +        return vfio_migration_init(vbasedev, info);
> >> +    }
> >> +
> >> +    return 0;
> >> +}
> >> +
> >> +void vfio_migration_finalize(VFIODevice *vbasedev) {
> >> +    if (!vbasedev->migration) {
> >> +        return;
> >> +    }
> >> +
> >> +    if (vbasedev->vm_state) {
> >> +        qemu_del_vm_change_state_handler(vbasedev->vm_state);
> >> +        
> >> remove_migration_state_change_notifier(&vbasedev->migration_state);
> >> +    }
> >> +
> >> +    if (vbasedev->migration_blocker) {
> >> +        migrate_del_blocker(vbasedev->migration_blocker);
> >> +        error_free(vbasedev->migration_blocker);
> >> +    }
> >> +
> >> +    g_free(vbasedev->migration);
> >> +}
> >> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> >> index a9036929b220..ab8217c9e249 100644
> >> --- a/include/hw/vfio/vfio-common.h
> >> +++ b/include/hw/vfio/vfio-common.h
> >> @@ -30,6 +30,8 @@
> >>  #include <linux/vfio.h>
> >>  #endif
> >>
> >> +#include "sysemu/sysemu.h"
> >> +
> >>  #define ERR_PREFIX "vfio error: %s: "
> >>  #define WARN_PREFIX "vfio warning: %s: "
> >>
> >> @@ -57,6 +59,16 @@ typedef struct VFIORegion {
> >>      uint8_t nr; /* cache the region number for debug */  } VFIORegion;
> >>
> >> +typedef struct VFIOMigration {
> >> +    struct {
> >> +        VFIORegion buffer;
> >> +        uint32_t index;
> >> +    } region;
> >> +    uint64_t pending_precopy_only;
> >> +    uint64_t pending_compatible;
> >> +    uint64_t pending_postcopy;
> >> +} VFIOMigration;
> >> +
> >>  typedef struct VFIOAddressSpace {
> >>      AddressSpace *as;
> >>      QLIST_HEAD(, VFIOContainer) containers; @@ -116,6 +128,12 @@ typedef
> >> struct VFIODevice {
> >>      unsigned int num_irqs;
> >>      unsigned int num_regions;
> >>      unsigned int flags;
> >> +    uint32_t device_state;
> >> +    VMChangeStateEntry *vm_state;
> >> +    int vm_running;
> >> +    Notifier migration_state;
> >> +    VFIOMigration *migration;
> >> +    Error *migration_blocker;
> >>  } VFIODevice;
> >>
> >>  struct VFIODeviceOps {
> >> @@ -193,4 +211,9 @@ int vfio_spapr_create_window(VFIOContainer
> >> *container,  int vfio_spapr_remove_window(VFIOContainer *container,
> >>                               hwaddr offset_within_address_space);
> >>
> >> +int vfio_migration_probe(VFIODevice *vbasedev, Error **errp); void
> >> +vfio_migration_finalize(VFIODevice *vbasedev); void
> >> +vfio_get_dirty_page_list(VFIODevice *vbasedev, uint64_t start_addr,
> >> +                               uint64_t pfn_count);
> >> +
> >>  #endif /* HW_VFIO_VFIO_COMMON_H */
> >> --
> >> 2.7.0
> >>
> > 



reply via email to

[Prev in Thread] Current Thread [Next in Thread]