[PATCH v2 06/17] conf: Add 'fdgroup' attribute for 'file' disks
Peter Krempa
pkrempa at redhat.com
Mon Jan 9 12:18:44 UTC 2023
The 'fdgroup' will allow users to specify a passed FD (via the
'virDomainFDAssociate()' API) to be used instead of opening a path.
This is useful in cases when e.g. the file is not accessible from inside
a container.
Since this uses the same disk type as when we open files via names this
patch also introduces a hypervisor feature which the hypervisor asserts
that code paths are ready for this possibility.
Signed-off-by: Peter Krempa <pkrempa at redhat.com>
Reviewed-by: Pavel Hrdina <phrdina at redhat.com>
---
docs/formatdomain.rst | 8 +++++
src/conf/domain_conf.c | 2 ++
src/conf/domain_conf.h | 1 +
src/conf/domain_postparse.c | 9 +++++
src/conf/schemas/domaincommon.rng | 3 ++
src/conf/storage_source_conf.c | 2 ++
src/conf/storage_source_conf.h | 1 +
src/security/virt-aa-helper.c | 3 +-
tests/qemuxml2argvdata/disk-source-fd.xml | 40 +++++++++++++++++++++++
9 files changed, 68 insertions(+), 1 deletion(-)
create mode 100644 tests/qemuxml2argvdata/disk-source-fd.xml
diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
index d7fffc6e0b..109a2ac45a 100644
--- a/docs/formatdomain.rst
+++ b/docs/formatdomain.rst
@@ -2701,6 +2701,14 @@ paravirtualized driver is specified via the ``disk`` element.
``file``
The ``file`` attribute specifies the fully-qualified path to the file
holding the disk. :since:`Since 0.0.3`
+
+ :since:`Since 9.0.0` a new optional attribute ``fdgroup`` can be added
+ instructing to access the disk via file descriptiors associated to the
+ domain object via the ``virDomainFDAssociate()`` API rather than opening
+ the files. The files do not necessarily have to be accessible by libvirt
+ via the filesystem. The filename passed via ``file`` can still be used
+ to generate paths to write into image metadata when doing block operations
+ but libvirt will not access these natively.
``block``
The ``dev`` attribute specifies the fully-qualified path to the host
device to serve as the disk. :since:`Since 0.0.3`
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index d16a247a45..6d27229e99 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -7345,6 +7345,7 @@ virDomainStorageSourceParse(xmlNodePtr node,
switch (src->type) {
case VIR_STORAGE_TYPE_FILE:
src->path = virXMLPropString(node, "file");
+ src->fdgroup = virXMLPropString(node, "fdgroup");
break;
case VIR_STORAGE_TYPE_BLOCK:
src->path = virXMLPropString(node, "dev");
@@ -21877,6 +21878,7 @@ virDomainDiskSourceFormat(virBuffer *buf,
switch (src->type) {
case VIR_STORAGE_TYPE_FILE:
virBufferEscapeString(&attrBuf, " file='%s'", src->path);
+ virBufferEscapeString(&attrBuf, " fdgroup='%s'", src->fdgroup);
break;
case VIR_STORAGE_TYPE_BLOCK:
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 9e281692ff..c1f1fccf62 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -3167,6 +3167,7 @@ typedef enum {
VIR_DOMAIN_DEF_FEATURE_NO_BOOT_ORDER = (1 << 6),
VIR_DOMAIN_DEF_FEATURE_FW_AUTOSELECT = (1 << 7),
VIR_DOMAIN_DEF_FEATURE_NET_MODEL_STRING = (1 << 8),
+ VIR_DOMAIN_DEF_FEATURE_DISK_FD = (1 << 9),
} virDomainDefFeatures;
diff --git a/src/conf/domain_postparse.c b/src/conf/domain_postparse.c
index 9a3e8f494c..d1f0b80338 100644
--- a/src/conf/domain_postparse.c
+++ b/src/conf/domain_postparse.c
@@ -885,6 +885,15 @@ virDomainDeviceDefPostParseCheckFeatures(virDomainDeviceDef *dev,
return -1;
}
+ if (dev->type == VIR_DOMAIN_DEVICE_DISK &&
+ dev->data.disk->src->fdgroup &&
+ UNSUPPORTED(VIR_DOMAIN_DEF_FEATURE_DISK_FD)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+ _("driver does not support FD passing for disk '%s'"),
+ dev->data.disk->dst);
+ return -1;
+ }
+
return 0;
}
#undef UNSUPPORTED
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng
index c588a48fd2..ccc114beff 100644
--- a/src/conf/schemas/domaincommon.rng
+++ b/src/conf/schemas/domaincommon.rng
@@ -1806,6 +1806,9 @@
<ref name="vmwarePath"/>
</choice>
</attribute>
+ <optional>
+ <attribute name="fdgroup"/>
+ </optional>
</optional>
<ref name="diskSourceCommon"/>
<optional>
diff --git a/src/conf/storage_source_conf.c b/src/conf/storage_source_conf.c
index ad9ff36ff1..4b1df19ab4 100644
--- a/src/conf/storage_source_conf.c
+++ b/src/conf/storage_source_conf.c
@@ -817,6 +817,7 @@ virStorageSourceCopy(const virStorageSource *src,
def->drv = NULL;
def->path = g_strdup(src->path);
+ def->fdgroup = g_strdup(src->fdgroup);
def->volume = g_strdup(src->volume);
def->relPath = g_strdup(src->relPath);
def->backingStoreRaw = g_strdup(src->backingStoreRaw);
@@ -1123,6 +1124,7 @@ virStorageSourceClear(virStorageSource *def)
return;
VIR_FREE(def->path);
+ VIR_FREE(def->fdgroup);
VIR_FREE(def->volume);
VIR_FREE(def->snapshot);
VIR_FREE(def->configFile);
diff --git a/src/conf/storage_source_conf.h b/src/conf/storage_source_conf.h
index 7c99ac8976..ef82104e6c 100644
--- a/src/conf/storage_source_conf.h
+++ b/src/conf/storage_source_conf.h
@@ -289,6 +289,7 @@ struct _virStorageSource {
unsigned int id; /* backing chain identifier, 0 is unset */
virStorageType type;
char *path;
+ char *fdgroup; /* name of group of file descriptors the user wishes to use instead of 'path' */
int protocol; /* virStorageNetProtocol */
char *volume; /* volume name for remote storage */
char *snapshot; /* for storage systems supporting internal snapshots */
diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
index 53a1cd1048..c8db925094 100644
--- a/src/security/virt-aa-helper.c
+++ b/src/security/virt-aa-helper.c
@@ -607,7 +607,8 @@ virDomainDefParserConfig virAAHelperDomainDefParserConfig = {
.features = VIR_DOMAIN_DEF_FEATURE_MEMORY_HOTPLUG |
VIR_DOMAIN_DEF_FEATURE_OFFLINE_VCPUPIN |
VIR_DOMAIN_DEF_FEATURE_INDIVIDUAL_VCPUS |
- VIR_DOMAIN_DEF_FEATURE_NET_MODEL_STRING,
+ VIR_DOMAIN_DEF_FEATURE_NET_MODEL_STRING |
+ VIR_DOMAIN_DEF_FEATURE_DISK_FD,
};
static int
diff --git a/tests/qemuxml2argvdata/disk-source-fd.xml b/tests/qemuxml2argvdata/disk-source-fd.xml
new file mode 100644
index 0000000000..d8c47fa364
--- /dev/null
+++ b/tests/qemuxml2argvdata/disk-source-fd.xml
@@ -0,0 +1,40 @@
+<domain type='qemu'>
+ <name>QEMUGuest1</name>
+ <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+ <memory unit='KiB'>219136</memory>
+ <currentMemory unit='KiB'>219136</currentMemory>
+ <vcpu placement='static'>1</vcpu>
+ <os>
+ <type arch='x86_64' machine='pc'>hvm</type>
+ <boot dev='hd'/>
+ </os>
+ <clock offset='utc'/>
+ <on_poweroff>destroy</on_poweroff>
+ <on_reboot>restart</on_reboot>
+ <on_crash>destroy</on_crash>
+ <devices>
+ <emulator>/usr/bin/qemu-system-x86_64</emulator>
+ <disk type='file' device='disk'>
+ <driver name='qemu' type='qcow2'/>
+ <source file='/path/to/blah' fdgroup='testgroup2'/>
+ <target dev='vde' bus='virtio'/>
+ </disk>
+ <disk type='file' device='disk'>
+ <driver name='qemu' type='qcow2'/>
+ <source file='/var/lib/libvirt/images/rhel7.1484071880' fdgroup='testgroup5'/>
+ <backingStore type='file'>
+ <format type='qcow2'/>
+ <source file='/var/lib/libvirt/images/rhel7.1484071877' fdgroup='testgroup6'/>
+ <backingStore type='file'>
+ <format type='qcow2'/>
+ <source file='/var/lib/libvirt/images/rhel7.1484071876'/>
+ <backingStore/>
+ </backingStore>
+ </backingStore>
+ <target dev='vdf' bus='virtio'/>
+ </disk>
+ <controller type='usb'/>
+ <controller type='pci' model='pci-root'/>
+ <memballoon model='virtio'/>
+ </devices>
+</domain>
--
2.38.1
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