Re: [libvirt PATCH 6/6] qemu: implement vhost-user-blk support
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(a)redhat.com>
---
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 ?)