Re: [PATCH 5/5] vfio/migration: support device memory capability

[Zhao Yan <yan.y.zhao@intel.com>]

On Wed, Feb 20, 2019 at 11:14:24AM +0100, Christophe de Dinechin wrote:
> 
> 
> > On 20 Feb 2019, at 08:58, Zhao Yan <yan.y.zhao@intel.com> wrote:
> > 
> > On Tue, Feb 19, 2019 at 03:42:36PM +0100, Christophe de Dinechin wrote:
> >> 
> >> 
> >>> On 19 Feb 2019, at 09:53, Yan Zhao <yan.y.zhao@intel.com> wrote:
> >>> 
> >>> If a device has device memory capability, save/load data from device memory
> >>> in pre-copy and stop-and-copy phases.
> >>> 
> >>> LOGGING state is set for device memory for dirty page logging:
> >>> in LOGGING state, get device memory returns whole device memory snapshot;
> >>> outside LOGGING state, get device memory returns dirty data since last get
> >>> operation.
> >>> 
> >>> Usually, device memory is very big, qemu needs to chunk it into several
> >>> pieces each with size of device memory region.
> >>> 
> >>> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> >>> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> >>> ---
> >>> hw/vfio/migration.c | 235 ++++++++++++++++++++++++++++++++++++++++++++++++++--
> >>> hw/vfio/pci.h       |   1 +
> >>> 2 files changed, 231 insertions(+), 5 deletions(-)
> >>> 
> >>> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> >>> index 16d6395..f1e9309 100644
> >>> --- a/hw/vfio/migration.c
> >>> +++ b/hw/vfio/migration.c
> >>> @@ -203,6 +203,201 @@ static int vfio_load_data_device_config(VFIOPCIDevice *vdev,
> >>>    return 0;
> >>> }
> >>> 
> >>> +static int vfio_get_device_memory_size(VFIOPCIDevice *vdev)
> >>> +{
> >>> +    VFIODevice *vbasedev = &vdev->vbasedev;
> >>> +    VFIORegion *region_ctl =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> >>> +    uint64_t len;
> >>> +    int sz;
> >>> +
> >>> +    sz = sizeof(len);
> >>> +    if (pread(vbasedev->fd, &len, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.size))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to get length of device memory”);
> >> 
> >> s/length/size/ ? (to be consistent with function name)
> > 
> > ok. thanks
> >>> +        return -1;
> >>> +    }
> >>> +    vdev->migration->devmem_size = len;
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +static int vfio_set_device_memory_size(VFIOPCIDevice *vdev, uint64_t size)
> >>> +{
> >>> +    VFIODevice *vbasedev = &vdev->vbasedev;
> >>> +    VFIORegion *region_ctl =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> >>> +    int sz;
> >>> +
> >>> +    sz = sizeof(size);
> >>> +    if (pwrite(vbasedev->fd, &size, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.size))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to set length of device comemory”);
> >> 
> >> What is comemory? Typo?
> > 
> > Right, typo. should be "memory" :)
> >> 
> >> Same comment about length vs size
> >> 
> > got it. thanks
> > 
> >>> +        return -1;
> >>> +    }
> >>> +    vdev->migration->devmem_size = size;
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +static
> >>> +int vfio_save_data_device_memory_chunk(VFIOPCIDevice *vdev, QEMUFile *f,
> >>> +                                    uint64_t pos, uint64_t len)
> >>> +{
> >>> +    VFIODevice *vbasedev = &vdev->vbasedev;
> >>> +    VFIORegion *region_ctl =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> >>> +    VFIORegion *region_devmem =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> >>> +    void *dest;
> >>> +    uint32_t sz;
> >>> +    uint8_t *buf = NULL;
> >>> +    uint32_t action = VFIO_DEVICE_DATA_ACTION_GET_BUFFER;
> >>> +
> >>> +    if (len > region_devmem->size) {
> >> 
> >> Is it intentional that there is no error_report here?
> >> 
> > an error_report here may be better.
> >>> +        return -1;
> >>> +    }
> >>> +
> >>> +    sz = sizeof(pos);
> >>> +    if (pwrite(vbasedev->fd, &pos, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.pos))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to set save buffer pos");
> >>> +        return -1;
> >>> +    }
> >>> +    sz = sizeof(action);
> >>> +    if (pwrite(vbasedev->fd, &action, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.action))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to set save buffer action");
> >>> +        return -1;
> >>> +    }
> >>> +
> >>> +    if (!vfio_device_state_region_mmaped(region_devmem)) {
> >>> +        buf = g_malloc(len);
> >>> +        if (buf == NULL) {
> >>> +            error_report("vfio: Failed to allocate memory for migrate”);
> >> s/migrate/migration/ ?
> > 
> > yes, thanks
> >>> +            return -1;
> >>> +        }
> >>> +        if (pread(vbasedev->fd, buf, len, region_devmem->fd_offset) != len) {
> >>> +            error_report("vfio: error load device memory buffer”);
> >> s/load/loading/ ?
> > error to load? :)
> 
> I’d check with a native speaker, but I believe it’s “error loading”.
> 
> To me (to be checked), the two sentences don’t have the same meaning:
> 
> “It is an error to load device memory buffer” -> “You are not allowed to do that”
> “I had an error loading device memory buffer” -> “I tried, but it failed"
>
haha, ok, I'll change it to loading, thanks :)
> > 
> >>> +            return -1;
> >>> +        }
> >>> +        qemu_put_be64(f, len);
> >>> +        qemu_put_be64(f, pos);
> >>> +        qemu_put_buffer(f, buf, len);
> >>> +        g_free(buf);
> >>> +    } else {
> >>> +        dest = region_devmem->mmaps[0].mmap;
> >>> +        qemu_put_be64(f, len);
> >>> +        qemu_put_be64(f, pos);
> >>> +        qemu_put_buffer(f, dest, len);
> >>> +    }
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +static int vfio_save_data_device_memory(VFIOPCIDevice *vdev, QEMUFile *f)
> >>> +{
> >>> +    VFIORegion *region_devmem =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> >>> +    uint64_t total_len = vdev->migration->devmem_size;
> >>> +    uint64_t pos = 0;
> >>> +
> >>> +    qemu_put_be64(f, total_len);
> >>> +    while (pos < total_len) {
> >>> +        uint64_t len = region_devmem->size;
> >>> +
> >>> +        if (pos + len >= total_len) {
> >>> +            len = total_len - pos;
> >>> +        }
> >>> +        if (vfio_save_data_device_memory_chunk(vdev, f, pos, len)) {
> >>> +            return -1;
> >>> +        }
> >> 
> >> I don’t see where pos is incremented in this loop
> >> 
> > yes, missing one line "pos += len;"
> > Currently, code is not verified in hardware with device memory cap on.
> > Thanks:)
> >>> +    }
> >>> +
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +static
> >>> +int vfio_load_data_device_memory_chunk(VFIOPCIDevice *vdev, QEMUFile *f,
> >>> +                                uint64_t pos, uint64_t len)
> >>> +{
> >>> +    VFIODevice *vbasedev = &vdev->vbasedev;
> >>> +    VFIORegion *region_ctl =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_CTL];
> >>> +    VFIORegion *region_devmem =
> >>> +        &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY];
> >>> +
> >>> +    void *dest;
> >>> +    uint32_t sz;
> >>> +    uint8_t *buf = NULL;
> >>> +    uint32_t action = VFIO_DEVICE_DATA_ACTION_SET_BUFFER;
> >>> +
> >>> +    if (len > region_devmem->size) {
> >> 
> >> error_report?
> > 
> > seems better to add error_report.
> >>> +        return -1;
> >>> +    }
> >>> +
> >>> +    sz = sizeof(pos);
> >>> +    if (pwrite(vbasedev->fd, &pos, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.pos))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to set device memory buffer pos");
> >>> +        return -1;
> >>> +    }
> >>> +    if (!vfio_device_state_region_mmaped(region_devmem)) {
> >>> +        buf = g_malloc(len);
> >>> +        if (buf == NULL) {
> >>> +            error_report("vfio: Failed to allocate memory for migrate");
> >>> +            return -1;
> >>> +        }
> >>> +        qemu_get_buffer(f, buf, len);
> >>> +        if (pwrite(vbasedev->fd, buf, len,
> >>> +                    region_devmem->fd_offset) != len) {
> >>> +            error_report("vfio: Failed to load devie memory buffer");
> >>> +            return -1;
> >>> +        }
> >>> +        g_free(buf);
> >>> +    } else {
> >>> +        dest = region_devmem->mmaps[0].mmap;
> >>> +        qemu_get_buffer(f, dest, len);
> >>> +    }
> >>> +
> >>> +    sz = sizeof(action);
> >>> +    if (pwrite(vbasedev->fd, &action, sz,
> >>> +                region_ctl->fd_offset +
> >>> +                offsetof(struct vfio_device_state_ctl, device_memory.action))
> >>> +            != sz) {
> >>> +        error_report("vfio: Failed to set load device memory buffer action");
> >>> +        return -1;
> >>> +    }
> >>> +
> >>> +    return 0;
> >>> +
> >>> +}
> >>> +
> >>> +static int vfio_load_data_device_memory(VFIOPCIDevice *vdev,
> >>> +                        QEMUFile *f, uint64_t total_len)
> >>> +{
> >>> +    uint64_t pos = 0, len = 0;
> >>> +
> >>> +    vfio_set_device_memory_size(vdev, total_len);
> >>> +
> >>> +    while (pos + len < total_len) {
> >>> +        len = qemu_get_be64(f);
> >>> +        pos = qemu_get_be64(f);
> >> 
> >> Nit: load reads len/pos in the loop, whereas save does it in the
> >> inner function (vfio_save_data_device_memory_chunk)
> > right, load has to read len/pos in the loop.
> >> 
> >>> +
> >>> +        vfio_load_data_device_memory_chunk(vdev, f, pos, len);
> >>> +    }
> >>> +
> >>> +    return 0;
> >>> +}
> >>> +
> >>> +
> >>> static int vfio_set_dirty_page_bitmap_chunk(VFIOPCIDevice *vdev,
> >>>        uint64_t start_addr, uint64_t page_nr)
> >>> {
> >>> @@ -377,6 +572,10 @@ static void vfio_save_live_pending(QEMUFile *f, void *opaque,
> >>>        return;
> >>>    }
> >>> 
> >>> +    /* get dirty data size of device memory */
> >>> +    vfio_get_device_memory_size(vdev);
> >>> +
> >>> +    *res_precopy_only += vdev->migration->devmem_size;
> >>>    return;
> >>> }
> >>> 
> >>> @@ -388,7 +587,9 @@ static int vfio_save_iterate(QEMUFile *f, void *opaque)
> >>>        return 0;
> >>>    }
> >>> 
> >>> -    return 0;
> >>> +    qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY);
> >>> +    /* get dirty data of device memory */
> >>> +    return vfio_save_data_device_memory(vdev, f);
> >>> }
> >>> 
> >>> static void vfio_pci_load_config(VFIOPCIDevice *vdev, QEMUFile *f)
> >>> @@ -458,6 +659,10 @@ static int vfio_load_state(QEMUFile *f, void *opaque, int version_id)
> >>>            len = qemu_get_be64(f);
> >>>            vfio_load_data_device_config(vdev, f, len);
> >>>            break;
> >>> +        case VFIO_SAVE_FLAG_DEVMEMORY:
> >>> +            len = qemu_get_be64(f);
> >>> +            vfio_load_data_device_memory(vdev, f, len);
> >>> +            break;
> >>>        default:
> >>>            ret = -EINVAL;
> >>>        }
> >>> @@ -503,6 +708,13 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
> >>>    VFIOPCIDevice *vdev = opaque;
> >>>    int rc = 0;
> >>> 
> >>> +    if (vfio_device_data_cap_device_memory(vdev)) {
> >>> +        qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY | VFIO_SAVE_FLAG_CONTINUE);
> >>> +        /* get dirty data of device memory */
> >>> +        vfio_get_device_memory_size(vdev);
> >>> +        rc = vfio_save_data_device_memory(vdev, f);
> >>> +    }
> >>> +
> >>>    qemu_put_byte(f, VFIO_SAVE_FLAG_PCI | VFIO_SAVE_FLAG_CONTINUE);
> >>>    vfio_pci_save_config(vdev, f);
> >>> 
> >>> @@ -515,12 +727,22 @@ static int vfio_save_complete_precopy(QEMUFile *f, void *opaque)
> >>> 
> >>> static int vfio_save_setup(QEMUFile *f, void *opaque)
> >>> {
> >>> +    int rc = 0;
> >>>    VFIOPCIDevice *vdev = opaque;
> >>> -    qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP);
> >>> +
> >>> +    if (vfio_device_data_cap_device_memory(vdev)) {
> >>> +        qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP | VFIO_SAVE_FLAG_CONTINUE);
> >>> +        qemu_put_byte(f, VFIO_SAVE_FLAG_DEVMEMORY);
> >>> +        /* get whole snapshot of device memory */
> >>> +        vfio_get_device_memory_size(vdev);
> >>> +        rc = vfio_save_data_device_memory(vdev, f);
> >>> +    } else {
> >>> +        qemu_put_byte(f, VFIO_SAVE_FLAG_SETUP);
> >>> +    }
> >>> 
> >>>    vfio_set_device_state(vdev, VFIO_DEVICE_STATE_RUNNING |
> >>>            VFIO_DEVICE_STATE_LOGGING);
> >>> -    return 0;
> >>> +    return rc;
> >>> }
> >>> 
> >>> static int vfio_load_setup(QEMUFile *f, void *opaque)
> >>> @@ -576,8 +798,11 @@ int vfio_migration_init(VFIOPCIDevice *vdev, Error **errp)
> >>>        goto error;
> >>>    }
> >>> 
> >>> -    if (vfio_device_data_cap_device_memory(vdev)) {
> >>> -        error_report("No suppport of data cap device memory Yet");
> >>> +    if (vfio_device_data_cap_device_memory(vdev) &&
> >>> +            vfio_device_state_region_setup(vdev,
> >>> +              &vdev->migration->region[VFIO_DEVSTATE_REGION_DATA_DEVICE_MEMORY],
> >>> +              VFIO_REGION_SUBTYPE_DEVICE_STATE_DATA_MEMORY,
> >>> +              "device-state-data-device-memory")) {
> >>>        goto error;
> >>>    }
> >>> 
> >>> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> >>> index 4b7b1bb..a2cc64b 100644
> >>> --- a/hw/vfio/pci.h
> >>> +++ b/hw/vfio/pci.h
> >>> @@ -69,6 +69,7 @@ typedef struct VFIOMigration {
> >>>    uint32_t data_caps;
> >>>    uint32_t device_state;
> >>>    uint64_t devconfig_size;
> >>> +    uint64_t devmem_size;
> >>>    VMChangeStateEntry *vm_state;
> >>> } VFIOMigration;
> >>> 
> >>> -- 
> >>> 2.7.4
> >>> 
> >>> _______________________________________________
> >>> intel-gvt-dev mailing list
> >>> intel-gvt-dev@lists.freedesktop.org
> >>> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
> >> 
> >> _______________________________________________
> >> intel-gvt-dev mailing list
> >> intel-gvt-dev@lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
>