Hi Nathan, > -----Original Message----- > From: Nathan Chen <[email protected]> > Sent: 17 February 2026 23:20 > To: [email protected] > Cc: Shameer Kolothum Thodi <[email protected]>; Nicolin Chen > <[email protected]>; Nathan Chen <[email protected]>; Matt Ochs > <[email protected]> > Subject: [RFC PATCH 0/3] qemu: Support vCMDQ > > Hi, > > This is a follow up to the previous RFC patchset [0] for supporting > Tegra241 vCMDQ, separated out from the series for accelerated SMMUv3. > > This patchset is tested with Shameer's v2 qemu series [1] for > vCMDQ support. The accelerated SMMUv3 series for qemu and Libvirt [2] > are pre-requisites for vCMDQ support, as accelerated SMMUv3 must be > enabled alongside vCMDQ. > > A new 'cmdqv' <iommu> driver attribute is introduced to toggle > enabling vCMDQ support. An additional 'identifier' <iommu> driver > attribute is introduced to specify an enumeration-independent > SMMUv3 device identifier. This identifier is used so that both > Tegra DSDT and SMMUv3 IORT use the same identifier.
Though QEMU SMMUv3 introduces an additional "identifier" property for ACPI tables to use, it is not intended for users or management layer to specify. QEMU internally populates these during SMMUv3 device instance realization. In short, libvirt doesn't have to set this. In case it needs an id for something, can always use the default QOM device "id" field. eg: -device arm-smmuv3,primary-bus=pcie.1,id=smmuv3.1-pxb1,.. Thanks, Shameer
