From: Sam Li <faithilikerun@xxxxxxxxx> Add the documentation about the example of using virtio-blk driver to pass the zoned block devices through to the guest. Signed-off-by: Sam Li <faithilikerun@xxxxxxxxx> Message-id: 20230407082528.18841-6-faithilikerun@xxxxxxxxx [Fix Sphinx indentation error by turning command-lines into pre-formatted text. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> --- docs/devel/zoned-storage.rst | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/docs/devel/zoned-storage.rst b/docs/devel/zoned-storage.rst index 6a36133e51..e02500c8a3 100644 --- a/docs/devel/zoned-storage.rst +++ b/docs/devel/zoned-storage.rst @@ -38,6 +38,25 @@ When the BlockBackend's BlockLimits model reports a zoned storage device, users like the virtio-blk emulation or the qemu-io-cmds.c utility can use block layer APIs for zoned storage emulation or testing. -For example, to test zone_report on a null_blk device using qemu-io is: -$ path/to/qemu-io --image-opts -n driver=host_device,filename=/dev/nullb0 --c "zrp offset nr_zones" +For example, to test zone_report on a null_blk device using qemu-io is:: + + $ path/to/qemu-io --image-opts -n driver=host_device,filename=/dev/nullb0 -c "zrp offset nr_zones" + +To expose the host's zoned block device through virtio-blk, the command line +can be (includes the -device parameter):: + + -blockdev node-name=drive0,driver=host_device,filename=/dev/nullb0,cache.direct=on \ + -device virtio-blk-pci,drive=drive0 + +Or only use the -drive parameter:: + + -driver driver=host_device,file=/dev/nullb0,if=virtio,cache.direct=on + +Additionally, QEMU has several ways of supporting zoned storage, including: +(1) Using virtio-scsi: --device scsi-block allows for the passing through of +SCSI ZBC devices, enabling the attachment of ZBC or ZAC HDDs to QEMU. +(2) PCI device pass-through: While NVMe ZNS emulation is available for testing +purposes, it cannot yet pass through a zoned device from the host. To pass on +the NVMe ZNS device to the guest, use VFIO PCI pass the entire NVMe PCI adapter +through to the guest. Likewise, an HDD HBA can be passed on to QEMU all HDDs +attached to the HBA. -- 2.39.2
