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

[Nicolin Chen]

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 at 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