On Tue, Feb 02, 2021 at 16:04:12 +0100, Pavel Hrdina wrote:
> Implements QEMU support for vhost-user-blk together with live
> hotplug/unplug.
>
> Signed-off-by: Pavel Hrdina <phrdina@xxxxxxxxxx>
> ---
> src/qemu/qemu_block.c | 16 ++++
> src/qemu/qemu_block.h | 5 +
> src/qemu/qemu_command.c | 91 +++++++++++++++++--
> src/qemu/qemu_command.h | 8 ++
> src/qemu/qemu_domain.c | 5 +
> src/qemu/qemu_hotplug.c | 5 +-
> src/qemu/qemu_validate.c | 13 +++
> .../disk-vhostuser.x86_64-latest.args | 41 +++++++++
> tests/qemuxml2argvtest.c | 1 +
> 9 files changed, 176 insertions(+), 9 deletions(-)
> create mode 100644 tests/qemuxml2argvdata/disk-vhostuser.x86_64-latest.args
[...]
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 3e652e18b7..059126cfeb 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -1712,9 +1712,16 @@ qemuBuildDiskDeviceStr(const virDomainDef *def,
> break;
>
> case VIR_DOMAIN_DISK_BUS_VIRTIO:
> - if (qemuBuildVirtioDevStr(&opt, "virtio-blk", qemuCaps,
> - VIR_DOMAIN_DEVICE_DISK, disk) < 0) {
> - return NULL;
> + if (virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_VHOST_USER) {
> + if (qemuBuildVirtioDevStr(&opt, "vhost-user-blk", qemuCaps,
> + VIR_DOMAIN_DEVICE_DISK, disk) < 0) {
> + return NULL;
> + }
> + } else {
> + if (qemuBuildVirtioDevStr(&opt, "virtio-blk", qemuCaps,
> + VIR_DOMAIN_DEVICE_DISK, disk) < 0) {
> + return NULL;
> + }
Preferably, add a temporary string holding either "vhost-user-blk" or
"virtio-blk" and call qemuBuildVirtioDevStr just once, since all other
arguments are the same.
> }
>
> if (disk->iothread)
[...]
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 0c078a9388..aa6d539610 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -10581,6 +10581,11 @@ qemuDomainPrepareDiskSource(virDomainDiskDefPtr disk,
> disk->src->format = VIR_STORAGE_FILE_RAW;
> }
>
> + /* Nothing else to prepare as it will use -chardev instead
> + * of -blockdev/-drive option. */
> + if (disk->src->type == VIR_STORAGE_TYPE_VHOST_USER)
> + return 0;
The code above sets 'format' for storage pool backed disks, but since
format isn't something we'd be setting for vhost-user this exemption
should be at the beginning of the function.
> +
> if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV) &&
> !qemuDiskBusIsSD(disk->bus)) {
> if (qemuDomainPrepareDiskSourceBlockdev(disk, priv, cfg) < 0)
Missing stuff from this commit:
- hot-unplug support
- see qemuDomainRemoveDiskDevice where the chardev isn't deleted
- blockjob lockout
- qemuDomainDiskBlockJobIsSupported
- block iotune lockout
- possible better lockout for qemuDomainBlockPeek
- it will barf either that the file is not 'raw' or that it can't be
initialized
- possible better lockout for qemuDomainSetBlockThreshold
- "threshold currently can't be set for block device '%s'" <- it
will never be possible
- lockout for qemuDomainGetBlockInfo
- lockout for qemuDomainBlockResize
- lockout for qemuDomainBlockStats(Flags)
- handling in bulk stats (qemuDomainGetStatsBlockExportDisk ?)
