Currently, attaching zoned block devices (i.e., storage devices compliant to ZAC/ZBC standards) using several virtio methods doesn't work properly as zoned devices appear as regular block devices at the guest. This may cause unexpected i/o errors and, potentially, some data corruption.
To be more precise, attaching a zoned device via virtio-pci-blk, virtio-scsi-pci/scsi-disk or virtio-scsi-pci/scsi-hd demonstrates the above behavior. The virtio-scsi-pci/scsi-block method works with a recent patch. The virtio-scsi-pci/scsi-generic method also appears to handle zoned devices without problems. This patch set adds code to check if the backing device that is being opened is a zoned Host Managed device. If this is the case, the patch prohibits attaching such device for all use cases lacking proper zoned support. Host Aware zoned block devices are designed to work as regular block devices at a guest system that does not support ZBD. Therefore, this patch set doesn't prohibit attachment of Host Aware devices. Considering that there is still a couple of different working ways to attach a ZBD, this patch set provides a reasonable short-term solution for this problem. ZBD support for virtio-scsi-pci/scsi-disk and virtio-scsi-pci/scsi-hd does not seem as necessary. Users will be expected to attach zoned block devices via virtio-scsi-pci/scsi-block instead. This patch set contains some Linux-specific code. This code is necessary to obtain Zoned Block Device model value from Linux sysfs. History: v1 -> v2: - rework code to be permission-based - always allow Host Aware devices to be attached - add fix for Host Aware attachments aka RCAP output snoop v2 -> v3: - drop the patch for RCAP output snoop - merged separately v3 -> v4: - rebase to the current code v4 -> v5: - avoid checkpatch warning v5 -> v6: - address review comments from Stefan Hajnoczi Dmitry Fomichev (4): block: Add zoned device model property raw: Recognize zoned backing devices block/ide/scsi: Set BLK_PERM_SUPPORT_HM_ZONED raw: Don't open ZBDs if backend can't handle them block.c | 15 +++++++ block/file-posix.c | 89 +++++++++++++++++++++++++++++++++------ block/io.c | 5 +++ hw/block/block.c | 8 +++- hw/block/fdc.c | 5 ++- hw/block/nvme.c | 2 +- hw/block/virtio-blk.c | 2 +- hw/block/xen-block.c | 2 +- hw/ide/qdev.c | 2 +- hw/scsi/scsi-disk.c | 13 +++--- hw/scsi/scsi-generic.c | 2 +- hw/usb/dev-storage.c | 2 +- include/block/block.h | 19 ++++++++- include/block/block_int.h | 3 ++ include/hw/block/block.h | 3 +- 15 files changed, 141 insertions(+), 31 deletions(-) -- 2.21.0
