On Tue, Aug 11, 2026 at 11:50:45AM -0700, Nathan Chen via Devel wrote:
> From: Nathan Chen <[email protected]>
>
> Introduce support for "cmdqv" IOMMU attribute, which
> enables NVIDIA Tegra241 CMDQV, an extension for ARM
> SMMUv3. It supports passthroughs of physical SMMU-CMDQ
> linked command queue from host space to a VM.
>
> Signed-off-by: Nathan Chen <[email protected]>
> ---
> docs/formatdomain.rst | 6 ++++++
> src/conf/domain_conf.c | 15 +++++++++++++++
> src/conf/domain_conf.h | 1 +
> src/conf/domain_validate.c | 6 +++++-
> src/conf/schemas/domaincommon.rng | 5 +++++
> src/qemu/qemu_command.c | 1 +
> src/qemu/qemu_validate.c | 1 -
> 7 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst
> index 0b346a0952..2d5a34cb35 100644
> --- a/docs/formatdomain.rst
> +++ b/docs/formatdomain.rst
> @@ -9436,6 +9436,12 @@ Examples:
> devices.
> :since:`Since 12.7.0` (QEMU/KVM and ``smmuv3`` model only)
>
> + ``cmdqv``
> + The ``cmdqv`` attribute with possible values ``on`` and ``off`` can be
> used
> + to enable NVIDIA Tegra241 CMDQV, an extension for ARM SMMUv3 that
> supports
> + passthrough of physical SMMU-CMDQ linked command queue from host space
> to VM.
> + :since:`Since 12.7.0` (QEMU/KVM and ``smmuv3`` model only)
> +
It should mention the default value if accel is enabled like the other
attributes.
> ``ats``
> The ``ats`` attribute with possible values ``on`` and ``off`` can be
> used to enable reporting Address Translation Services capability to
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 9880339e42..42a0faca88 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -14758,6 +14758,10 @@ virDomainIOMMUDefParseXML(virDomainXMLOption *xmlopt,
> &iommu->accel) < 0)
> return NULL;
>
> + if (virXMLPropTristateSwitch(driver, "cmdqv", VIR_XML_PROP_NONE,
> + &iommu->cmdqv) < 0)
> + return NULL;
> +
> if (virXMLPropTristateSwitch(driver, "ats", VIR_XML_PROP_NONE,
> &iommu->ats) < 0)
> return NULL;
> @@ -16879,6 +16883,7 @@ virDomainIOMMUDefEquals(const virDomainIOMMUDef *a,
> a->dma_translation != b->dma_translation ||
> a->pci_bus != b->pci_bus ||
> a->accel != b->accel ||
> + a->cmdqv != b->cmdqv ||
> a->ats != b->ats ||
> a->ril != b->ril ||
> a->ssid_size != b->ssid_size ||
> @@ -22773,6 +22778,12 @@ virDomainIOMMUDefCheckABIStability(virDomainIOMMUDef
> *src,
> dst->accel, src->accel);
> return false;
> }
> + if (src->cmdqv != dst->cmdqv) {
> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Target domain IOMMU device cmdqv value '%1$d' does
> not match source '%2$d'"),
> + dst->cmdqv, src->cmdqv);
> + return false;
> + }
> if (src->ats != dst->ats) {
> virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> _("Target domain IOMMU device ATS value '%1$d' does
> not match source '%2$d'"),
> @@ -29271,6 +29282,10 @@ virDomainIOMMUDefFormat(virBuffer *buf,
> virBufferAsprintf(&driverAttrBuf, " accel='%s'",
> virTristateSwitchTypeToString(iommu->accel));
> }
> + if (iommu->cmdqv != VIR_TRISTATE_SWITCH_ABSENT) {
> + virBufferAsprintf(&driverAttrBuf, " cmdqv='%s'",
> + virTristateSwitchTypeToString(iommu->cmdqv));
> + }
> if (iommu->ats != VIR_TRISTATE_SWITCH_ABSENT) {
> virBufferAsprintf(&driverAttrBuf, " ats='%s'",
> virTristateSwitchTypeToString(iommu->ats));
> diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> index 2c017738e3..0c79bea015 100644
> --- a/src/conf/domain_conf.h
> +++ b/src/conf/domain_conf.h
> @@ -3106,6 +3106,7 @@ struct _virDomainIOMMUDef {
> virTristateSwitch pt;
> int granule; /* -1 means 'host', 0 unset, page size in KiB otherwise */
> virTristateSwitch accel;
> + virTristateSwitch cmdqv;
> virTristateSwitch ats;
> virTristateSwitch ril;
> int ssid_size;
> diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c
> index 710a891904..59b6c5f6d7 100644
> --- a/src/conf/domain_validate.c
> +++ b/src/conf/domain_validate.c
> @@ -3207,7 +3207,8 @@ virDomainIOMMUDefValidate(const virDomainIOMMUDef
> *iommu)
> (iommu->ats != VIR_TRISTATE_SWITCH_ABSENT ||
> iommu->ril != VIR_TRISTATE_SWITCH_ABSENT ||
> iommu->ssid_size >= 0 ||
> - iommu->oas >= 0)) {
> + iommu->oas >= 0 ||
> + iommu->cmdqv != VIR_TRISTATE_SWITCH_ABSENT)) {
For consistency with the other conditions I would move the check between
accel and ats.
Otherwise looks good.
Pavel
