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Re: [Qemu-devel] [PATCH v4 10/13] vfio: Add function to get dirty page l
From: |
Yan Zhao |
Subject: |
Re: [Qemu-devel] [PATCH v4 10/13] vfio: Add function to get dirty page list |
Date: |
Tue, 25 Jun 2019 20:40:39 -0400 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
On Thu, Jun 20, 2019 at 10:37:38PM +0800, Kirti Wankhede wrote:
> Dirty page tracking (.log_sync) is part of RAM copying state, where
> vendor driver provides the bitmap of pages which are dirtied by vendor
> driver through migration region and as part of RAM copy, those pages
> gets copied to file stream.
>
> To get dirty page bitmap:
> - write start address, page_size and pfn count.
> - read count of pfns copied.
> - Vendor driver should return 0 if driver doesn't have any page to
> report dirty in given range.
> - Vendor driver should return -1 to mark all pages dirty for given range.
> - read data_offset, where vendor driver has written bitmap.
> - read bitmap from 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/migration.c | 119
> ++++++++++++++++++++++++++++++++++++++++++
> include/hw/vfio/vfio-common.h | 2 +
> 2 files changed, 121 insertions(+)
>
> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c
> index e4895f91761d..68775b5dec11 100644
> --- a/hw/vfio/migration.c
> +++ b/hw/vfio/migration.c
> @@ -228,6 +228,125 @@ static int vfio_load_device_config_state(QEMUFile *f,
> void *opaque)
> return qemu_file_get_error(f);
> }
>
> +void vfio_get_dirty_page_list(VFIODevice *vbasedev,
> + uint64_t start_pfn,
> + uint64_t pfn_count,
> + uint64_t page_size)
> +{
> + VFIOMigration *migration = vbasedev->migration;
> + VFIORegion *region = &migration->region.buffer;
> + uint64_t count = 0;
> + int64_t copied_pfns = 0;
> + int ret;
> +
> + qemu_mutex_lock(&migration->lock);
> + ret = pwrite(vbasedev->fd, &start_pfn, sizeof(start_pfn),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + start_pfn));
> + if (ret < 0) {
> + error_report("Failed to set dirty pages start address %d %s",
> + ret, strerror(errno));
> + goto dpl_unlock;
> + }
> +
> + ret = pwrite(vbasedev->fd, &page_size, sizeof(page_size),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + page_size));
> + if (ret < 0) {
> + error_report("Failed to set dirty page size %d %s",
> + ret, strerror(errno));
> + goto dpl_unlock;
> + }
> +
> + ret = pwrite(vbasedev->fd, &pfn_count, sizeof(pfn_count),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + total_pfns));
> + if (ret < 0) {
> + error_report("Failed to set dirty page total pfns %d %s",
> + ret, strerror(errno));
> + goto dpl_unlock;
> + }
> +
> + do {
> + uint64_t bitmap_size, data_offset = 0;
> + void *buf = NULL;
> + bool buffer_mmaped = false;
> +
> + /* Read copied dirty pfns */
> + ret = pread(vbasedev->fd, &copied_pfns, sizeof(copied_pfns),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + copied_pfns));
> + if (ret < 0) {
> + error_report("Failed to get dirty pages bitmap count %d %s",
> + ret, strerror(errno));
> + goto dpl_unlock;
> + }
> +
> + if (copied_pfns == 0) {
> + /*
> + * copied_pfns could be 0 if driver doesn't have any page to
> + * report dirty in given range
> + */
> + break;
this copied_pfn is the dirty page count in which range?
if it is got each iteration, why break here rather than continue ?
consider there's a big region with pfn_count, and it is now breaked into
several smaller subregions, and copied_pfns is 0 in the first subregion,
it doesn't mean copied_pfns are all 0 in the remaining subregions.
> + } else if (copied_pfns == -1) {
> + /* Mark all pages dirty for this range */
> + cpu_physical_memory_set_dirty_range(start_pfn * page_size,
> + pfn_count * page_size,
> + DIRTY_MEMORY_MIGRATION);
> + break;
> + }
> +
> + bitmap_size = (BITS_TO_LONGS(copied_pfns) + 1) * sizeof(unsigned
> long);
> +
> + ret = pread(vbasedev->fd, &data_offset, sizeof(data_offset),
> + region->fd_offset + offsetof(struct
> vfio_device_migration_info,
> + data_offset));
> + if (ret != sizeof(data_offset)) {
> + error_report("Failed to get migration buffer data offset %d",
> + ret);
> + goto dpl_unlock;
> + }
> +
> + if (region->mmaps) {
> + int i;
> + for (i = 0; i < region->nr_mmaps; i++) {
> + if ((region->mmaps[i].offset >= data_offset) &&
> + (data_offset < region->mmaps[i].offset +
> + region->mmaps[i].size)) {
> + buf = region->mmaps[i].mmap + (data_offset -
> + region->mmaps[i].offset);
> + buffer_mmaped = true;
> + break;
> + }
> + }
> + }
> +
> + if (!buffer_mmaped) {
> + buf = g_malloc0(bitmap_size);
> +
> + ret = pread(vbasedev->fd, buf, bitmap_size,
> + region->fd_offset + data_offset);
> + if (ret != bitmap_size) {
> + error_report("Failed to get dirty pages bitmap %d", ret);
> + g_free(buf);
> + goto dpl_unlock;
> + }
> + }
> +
> + cpu_physical_memory_set_dirty_lebitmap((unsigned long *)buf,
> + (start_pfn + count) *
> page_size,
> + copied_pfns);
> + count += copied_pfns;
> +
here also. why it is count += copied_pfns.
> + if (!buffer_mmaped) {
> + g_free(buf);
> + }
> + } while (count < pfn_count);
> +
> +dpl_unlock:
> + qemu_mutex_unlock(&migration->lock);
> +}
> +
> /* ---------------------------------------------------------------------- */
>
> static int vfio_save_setup(QEMUFile *f, void *opaque)
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 1d26e6be8d48..423d6dbccace 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -224,5 +224,7 @@ int vfio_spapr_remove_window(VFIOContainer *container,
>
> 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_pfn,
> + uint64_t pfn_count, uint64_t page_size);
>
> #endif /* HW_VFIO_VFIO_COMMON_H */
> --
> 2.7.0
>
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, (continued)
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Alex Williamson, 2019/06/21
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Kirti Wankhede, 2019/06/21
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Alex Williamson, 2019/06/21
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Kirti Wankhede, 2019/06/21
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Alex Williamson, 2019/06/21
- Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Kirti Wankhede, 2019/06/24
Re: [Qemu-devel] [PATCH v4 08/13] vfio: Add save state functions to SaveVMHandlers, Yan Zhao, 2019/06/20
[Qemu-devel] [PATCH v4 09/13] vfio: Add load state functions to SaveVMHandlers, Kirti Wankhede, 2019/06/20
[Qemu-devel] [PATCH v4 10/13] vfio: Add function to get dirty page list, Kirti Wankhede, 2019/06/20
- Re: [Qemu-devel] [PATCH v4 10/13] vfio: Add function to get dirty page list,
Yan Zhao <=
[Qemu-devel] [PATCH v4 11/13] vfio: Add vfio_listerner_log_sync to mark dirty pages, Kirti Wankhede, 2019/06/20
[Qemu-devel] [PATCH v4 12/13] vfio: Make vfio-pci device migration capable., Kirti Wankhede, 2019/06/20
[Qemu-devel] [PATCH v4 13/13] vfio: Add trace events in migration code path, Kirti Wankhede, 2019/06/20
Re: [Qemu-devel] [PATCH v4 00/13] Add migration support for VFIO device, Yan Zhao, 2019/06/20