[libvirt] [PATCH 02/17] qemu: Introduce qemuDomainDeviceDefSkipController
John Ferlan
jferlan at redhat.com
Wed Dec 6 15:18:53 UTC 2017
On 12/05/2017 09:18 AM, Ján Tomko wrote:
> On Mon, Dec 04, 2017 at 08:38:52PM -0500, John Ferlan wrote:
>> In order to be able to reuse some code for both controller def
>> validation and command line building, create a convenience helper
>> that will perform the "skip" avoidance checks. It will also set
>> some flags to allow the caller to specifically skip (or fail)
>> depending on the result of the flag (as opposed to building up
>> some ever growing list of variables).
>>
>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>> ---
>> src/qemu/qemu_command.c | 61 +++++------------------------------
>> src/qemu/qemu_domain.c | 84
>> ++++++++++++++++++++++++++++++++++++++++++++++++-
>> src/qemu/qemu_domain.h | 12 +++++++
>> 3 files changed, 102 insertions(+), 55 deletions(-)
>>
>
> [...]
>
>> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
>> index 569bbd29e..d4c7674c0 100644
>> --- a/src/qemu/qemu_domain.c
>> +++ b/src/qemu/qemu_domain.c
>> @@ -3884,10 +3884,92 @@ qemuDomainDeviceDefValidateDisk(const
>> virDomainDiskDef *disk)
>> }
>>
>>
>> +/**
>> + * qemuDomainDeviceDefSkipController:
>> + * @controller: Controller to check
>> + * @def: Domain definition
>> + * @flags: qemuDomainDeviceSkipFlags to set if specific condition found
>> + *
>> + * Returns true if this controller can be skipped for command line
>> generation
>> + * or device validation
>
> We should not skip validation for implicit devices. Some of the checks
> added later are for implicit devices (PCI root, SATA controller).
>
> It would be enough to split out the logic of figuring out whether the
> controller is implicit out of command line generation.
>
After some more thought - I'm not sure it's really clear to me what
you're driving at.
The whole point of the Skip helper was to avoid duplicating checks in
specific ValidateController{IDE|PCI|SATA|USB} helpers. If we're not
building a command line for those, then what is the purpose of going
through Validation?
I suppose I could duplicate the same checks in the helpers, but that
didn't feel right. If I take the IDE check as an example, the IDE
validation would need code like Lin Ma's patches had, e.g.:
if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_IDE) {
/* No need to check implicit/builtin IDE controller */
if (controller->idx == 0 && qemuDomainHasBuiltinIDE(def))
return 0;
...
Personally, trying to reduce cut-copy-paste would be a gain.
>> + */
>> +bool
>> +qemuDomainDeviceDefSkipController(const virDomainControllerDef
>> *controller,
>> + const virDomainDef *def,
>> + unsigned int *flags)
>> +{
>> + /* skip USB controllers with type none.*/
>> + if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_USB &&
>> + controller->model == VIR_DOMAIN_CONTROLLER_MODEL_USB_NONE) {
>> + *flags |= QEMU_DOMAIN_DEVICE_SKIP_USB_CONTROLLER_FLAG;
>> + return true;
>> + }
>
> Simply returning true here (no USB controller is implicit) should
> suffice. The caller can figure out whether USB_NONE is present
> by going through the controllers array again (via virDomainDefHasUSB).
>
I'm just going to drop moving the USB checks into ValidateControllerUSB
- it seems you have an idea of what you'd like to see done and I'm fine
with reviewing that when/if it shows up on the list.
The whole reason for the flags argument was because of the very specific
USB checks being done in command line building. Since you clearly
understand those better than I do, for me to make progress it's best to
just defer to you.
Updated series to be sent shortly...
John
>> +
>> + /* skip pcie-root */
>> + if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_PCI &&
>> + controller->model == VIR_DOMAIN_CONTROLLER_MODEL_PCIE_ROOT)
>> + return true;
>> +
>> + /* Skip pci-root, except for pSeries guests (which actually
>> + * support more than one PCI Host Bridge per guest) */
>> + if (!qemuDomainIsPSeries(def) &&
>> + controller->type == VIR_DOMAIN_CONTROLLER_TYPE_PCI &&
>> + controller->model == VIR_DOMAIN_CONTROLLER_MODEL_PCI_ROOT)
>> + return true;
>> +
>> + /* first SATA controller on Q35 machines is implicit */
>> + if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_SATA &&
>> + controller->idx == 0 && qemuDomainIsQ35(def))
>> + return true;
>> +
>> + /* first IDE controller is implicit on various machines */
>> + if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_IDE &&
>> + controller->idx == 0 && qemuDomainHasBuiltinIDE(def))
>> + return true;
>> +
>> + if (controller->type == VIR_DOMAIN_CONTROLLER_TYPE_USB &&
>> + controller->model == -1 &&
>> + !qemuDomainIsQ35(def) &&
>> + !qemuDomainIsVirt(def)) {
>> +
>> + /* An appropriate default USB controller model should already
>> + * have been selected in qemuDomainDeviceDefPostParse(); if
>> + * we still have no model by now, we have to fall back to the
>> + * legacy USB controller.
>> + *
>> + * Note that we *don't* want to end up with the legacy USB
>> + * controller for q35 and virt machines, so we go ahead and
>> + * fail in qemuBuildControllerDevStr(); on the other hand,
>> + * for s390 machines we want to ignore any USB controller
>> + * (see 548ba43028 for the full story), so we skip
>> + * qemuBuildControllerDevStr() but we don't ultimately end
>> + * up adding the legacy USB controller */
>> + if (*flags & QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FLAG) {
>> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>> + _("Multiple legacy USB controllers are "
>> + "not supported"));
>
> A function returning bool where both options are valid should not be
> setting errors.
>
> For this error, validate can go through all the controllers. Command
> line generator should not care and we can get rid of the remaining two
> flags as their only purpose is to save us multiple passes through
> the controllers field.
>
>> + *flags |= QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FAIL_FLAG;
>> + }
>> + *flags |= QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FLAG;
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> +
>> static int
>> qemuDomainDeviceDefValidateController(const virDomainControllerDef
>> *controller,
>> - const virDomainDef *def
>> ATTRIBUTE_UNUSED)
>> + const virDomainDef *def)
>> {
>> + unsigned int flags = 0;
>> +
>> + if (qemuDomainDeviceDefSkipController(controller, def, &flags))
>> + return 0;
>> +
>> + if (flags & QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FAIL_FLAG)
>> + return -1;
>
> To possibly set this flag, SkipController must be called with non-zero
> flags, so this would be dead code.
>
> I'd rather go through def->controllers again to look for another legacy
> controller, just for the purpose of validation.
>
> Jan
>
>> +
>> switch ((virDomainControllerType) controller->type) {
>> case VIR_DOMAIN_CONTROLLER_TYPE_IDE:
>> case VIR_DOMAIN_CONTROLLER_TYPE_FDC:
>> diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
>> index c33af3671..5c9c55d38 100644
>> --- a/src/qemu/qemu_domain.h
>> +++ b/src/qemu/qemu_domain.h
>> @@ -999,4 +999,16 @@ qemuDomainPrepareDiskSource(virConnectPtr conn,
>> qemuDomainObjPrivatePtr priv,
>> virQEMUDriverConfigPtr cfg);
>>
>> +typedef enum {
>> + QEMU_DOMAIN_DEVICE_SKIP_USB_CONTROLLER_FLAG = (1 << 0),
>> + QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FLAG = (1 << 1),
>> + QEMU_DOMAIN_DEVICE_SKIP_USB_LEGACY_FAIL_FLAG = (1 << 2),
>> +} qemuDomainDeviceSkipFlags;
>> +
>> +bool
>> +qemuDomainDeviceDefSkipController(const virDomainControllerDef
>> *controller,
>> + const virDomainDef *def,
>> + unsigned int *flags);
>> +
>> +
>> #endif /* __QEMU_DOMAIN_H__ */
>> --
>> 2.13.6
>>
>> --
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