[PATCH v2 09/22] iommufd/viommu: Introduce IOMMUFD_OBJ_VCMDQ and its related struct

Nicolin Chen
2025-04-26T05:59:14Z

Add a new IOMMUFD_OBJ_VCMDQ with an iommufd_vcmdq structure, representing
a command queue type of physical HW passed to a user space VM. This vCMDQ
object, is a subset of vIOMMU resources of a physical IOMMU's, such as:
- NVIDIA's virtual command queue
- AMD vIOMMU's command buffer

Inroduce a struct iommufd_vcmdq and its allocator iommufd_vcmdq_alloc().
Also add a pair of viommu ops for iommufd to forward user space ioctls to
IOMMU drivers.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
include/linux/iommufd.h | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)

diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index ef0d3c4765cf..e91381aaec5a 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -37,6 +37,7 @@ enum iommufd_object_type {
IOMMUFD_OBJ_VIOMMU,
IOMMUFD_OBJ_VDEVICE,
IOMMUFD_OBJ_VEVENTQ,
+ IOMMUFD_OBJ_VCMDQ,
#ifdef CONFIG_IOMMUFD_TEST
IOMMUFD_OBJ_SELFTEST,
#endif
@@ -112,6 +113,14 @@ struct iommufd_vdevice {
u64 id; /* per-vIOMMU virtual ID */
};

+struct iommufd_vcmdq {
+ struct iommufd_object obj;
+ struct iommufd_ctx *ictx;
+ struct iommufd_viommu *viommu;
+ dma_addr_t addr;
+ size_t length;
+};
+
/**
* struct iommufd_viommu_ops - vIOMMU specific operations
* @destroy: Clean up all driver-specific parts of an iommufd_viommu. The memory
@@ -135,6 +144,13 @@ struct iommufd_vdevice {
* @vdevice_destroy: Clean up all driver-specific parts of an iommufd_vdevice.
* The memory of the vDEVICE will be free-ed by iommufd core
* after calling this op
+ * @vcmdq_alloc: Allocate a @type of iommufd_vcmdq as a user space command queue
+ * for a @viommu. @index carries the logical vcmdq ID (for a multi-
+ * queue case); @addr carries the guest physical base address of
+ * the queue memory; @length carries the size of the queue memory
+ * @vcmdq_destroy: Clean up all driver-specific parts of an iommufd_vcmdq. The
+ * memory of the iommufd_vcmdq will be free-ed by iommufd core
+ * after calling this op
*/
struct iommufd_viommu_ops {
void (*destroy)(struct iommufd_viommu *viommu);
@@ -147,6 +163,10 @@ struct iommufd_viommu_ops {
struct device *dev,
u64 virt_id);
void (*vdevice_destroy)(struct iommufd_vdevice *vdev);
+ struct iommufd_vcmdq *(*vcmdq_alloc)(struct iommufd_viommu *viommu,
+ unsigned int type, u32 index,
+ dma_addr_t addr, size_t length);
+ void (*vcmdq_destroy)(struct iommufd_vcmdq *vcmdq);
};

#if IS_ENABLED(CONFIG_IOMMUFD)
@@ -286,6 +306,21 @@ static inline int iommufd_viommu_report_event(struct iommufd_viommu *viommu,
ret; \
})

+#define iommufd_vcmdq_alloc(viommu, drv_struct, member) \
+ ({ \
+ drv_struct *ret; \
+ \
+ static_assert(__same_type(struct iommufd_viommu, *viommu)); \
+ static_assert(__same_type(struct iommufd_vcmdq, \
+ ((drv_struct *)NULL)->member)); \
+ static_assert(offsetof(drv_struct, member.obj) == 0); \
+ ret = (drv_struct *)_iommufd_object_alloc( \
+ viommu->ictx, sizeof(drv_struct), IOMMUFD_OBJ_VCMDQ); \
+ if (!IS_ERR(ret)) \
+ ret->member.viommu = viommu; \
+ ret; \
+ })
+
/* Helper for IOMMU driver to destroy structures created by allocators above */
#define iommufd_struct_destroy(ictx, drv_struct, member) \
({ \
--
2.43.0