A VMID held by a vSMMU is required to setup hardware (e.g. tegra241-cmdqv)
during its initialization. So, it should be allocated in the ->viommu_init
callback. This makes the VMID lifecycle unique than a VMID allocated for a
naked S2 attachment.

Introduce an INV_TYPE_S2_VMID_VSMMU to accommodate this case.

Note that a second device attaching to a nested domain associated with the
same vSMMU instance will have an INV_TYPE_S2_VMID_VSMMU and reuse the VMID
held by the vSMMU. Devices attaching directly to the nesting parent domain
will have an INV_TYPE_S2_VMID and shouldn't resue the VMID from the vSMMU.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <redacted>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  1 +
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 +++++++++++++++---
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 386ac75879c0..8365660282d5 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h

@@ -656,6 +656,7 @@ struct arm_smmu_cmdq_batch {
 enum arm_smmu_inv_type {
 	INV_TYPE_S1_ASID,
 	INV_TYPE_S2_VMID,
+	INV_TYPE_S2_VMID_VSMMU,
 	INV_TYPE_S2_VMID_S1_CLEAR,
 	INV_TYPE_ATS,
 	INV_TYPE_ATS_FULL,