10:57 a.m.
On 07/16/2015 08:23 AM, Ján Tomko wrote:
On Mon, Jun 22, 2015 at 05:05:07PM -0400, John Ferlan wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1210587 (completed)
>
> When generating the default drive address for a SCSI <disk> device,
> check the generated address to ensure it doesn't conflict with a SCSI
> <hostdev> address. The <disk> address generation algorithm uses the
> <target> "dev" name in order to determine which controller and unit
> in order to place the device. Since a SCSI <hostdev> device doesn't
> require a target device name, its placement on the guest SCSI address
> "could" conflict. For instance, if a SCSI <hostdev> exists at
> controller=0 unit=0 and an attempt to hotplug 'sda' into the guest
> made, there would be a conflict if the <hostdev> is already using
> /dev/sda.
>
> Signed-off-by: John Ferlan <jferlan(a)redhat.com>
> ---
> src/conf/domain_conf.c | 40 +++++++++++++++++++++++++++++-----------
> src/conf/domain_conf.h | 3 ++-
> src/qemu/qemu_command.c | 4 ++--
> src/vmx/vmx.c | 22 ++++++++++++----------
> src/vmx/vmx.h | 3 ++-
> 5 files changed, 47 insertions(+), 25 deletions(-)
>
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 6259d4a..0999e86 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -5672,7 +5672,8 @@ virDomainDiskFindByBusAndDst(virDomainDefPtr def,
>
> int
> virDomainDiskDefAssignAddress(virDomainXMLOptionPtr xmlopt,
> - virDomainDiskDefPtr def)
> + virDomainDiskDefPtr def,
> + const virDomainDef *vmdef)
> {
> int idx = virDiskNameToIndex(def->dst);
> if (idx < 0) {
> @@ -5683,7 +5684,10 @@ virDomainDiskDefAssignAddress(virDomainXMLOptionPtr xmlopt,
> }
>
> switch (def->bus) {
> - case VIR_DOMAIN_DISK_BUS_SCSI:
> + case VIR_DOMAIN_DISK_BUS_SCSI: {
> + unsigned int controller;
> + unsigned int unit;
> +
> def->info.type = VIR_DOMAIN_DEVICE_ADDRESS_TYPE_DRIVE;
>
> if (xmlopt->config.hasWideSCSIBus) {
> @@ -5692,22 +5696,36 @@ virDomainDiskDefAssignAddress(virDomainXMLOptionPtr xmlopt,
> * Unit 7 is the SCSI controller itself. Therefore unit 7
> * cannot be assigned to disks and is skipped.
> */
> - def->info.addr.drive.controller = idx / 15;
> - def->info.addr.drive.bus = 0;
> - def->info.addr.drive.unit = idx % 15;
> + controller = idx / 15;
> + unit = idx % 15;
>
> /* Skip the SCSI controller at unit 7 */
> - if (def->info.addr.drive.unit >= 7)
> - ++def->info.addr.drive.unit;
> + if (unit >= 7)
> + ++unit;
> } else {
> /* For a narrow SCSI bus we define the default mapping to be
> * 7 units per bus, 1 bus per controller, many controllers */
> - def->info.addr.drive.controller = idx / 7;
> - def->info.addr.drive.bus = 0;
> - def->info.addr.drive.unit = idx % 7;
> + controller = idx / 7;
> + unit = idx % 7;
> + }
> +
This mixes non-functional and functional changes.
OK - I can separate out out just the non-functional into its own patch.
Do you want me to send it out again or trust that I know what I'm doing?
> + if (virDomainDriveAddressIsUsedByHostdev(vmdef,
> +
VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI,
> + controller, 0, 0, unit)) {
> + virReportError(VIR_ERR_XML_ERROR,
> + _("address generated using disk target name
'%s' "
> + "may conflict with SCSI host device address
"
> + "controller='%u' bus='%u'
target='%u' unit='%u"),
> + def->dst, controller, 0, 0, unit);
'may conflict' sounds ambiguous. Either it does conflict and we should
reject it, or it does not and there is no error.
And this seems like a problem of libvirt's address generation algorithm,
not an XML error.
Jan
Right - it does conflict...
The issue is that the 'idx' is generated as a result of the target
device name ("dst"). The assumption being "sda" would be controller
=
unit = 0, 'sdb' would be ctlr = 0, unit = 1, 'sdc' would be ctlr = 0,
unit = 2, etc.
However, for hostdev's there is no such "dst" logic - it's a straight
assignment.
When the guest boots, whatever is assigned to "c = 0, u = 0" is assigned
to 'sda' (regardless of whether it's a hostdev or disk).
So if the hostdev which had it's address provided in the XML, but the
disk which didn't *and* is using "<target dev='sda'.../>",
then there's
a possible conflict because "sda" resolves to "c = 0, b = 0". The
error
message I guess should thus state :
"using disk target name '%s' conflicts with SCSI host device address
..."
Would you still call that an XML error or perhaps CONFIG_UNSUPPORTED
John