From: Elena Agostini <eagost...@nvidia.com>
Enable the possibility to expose a GPU memory area and make it
accessible from the CPU.
GPU memory has to be allocated via rte_gpu_mem_alloc().
This patch allows the gpudev library to map (and unmap),
through the GPU driver, a chunk of GPU memory and to return
a memory pointer usable by the CPU to access the GPU memory area.
Signed-off-by: Elena Agostini <eagost...@nvidia.com>
---
doc/guides/prog_guide/gpudev.rst | 9 +++++
drivers/gpu/cuda/cuda.c | 2 ++
lib/gpudev/gpudev.c | 61 ++++++++++++++++++++++++++++++++
lib/gpudev/gpudev_driver.h | 6 ++++
lib/gpudev/rte_gpudev.h | 49 +++++++++++++++++++++++++
lib/gpudev/version.map | 2 ++
6 files changed, 129 insertions(+)
diff --git a/doc/guides/prog_guide/gpudev.rst b/doc/guides/prog_guide/gpudev.rst
index ff4626812b..b774ec77f9 100644
--- a/doc/guides/prog_guide/gpudev.rst
+++ b/doc/guides/prog_guide/gpudev.rst
@@ -73,6 +73,15 @@ Later, it's also possible to unregister that memory with
gpudev.
CPU memory registered outside of the gpudev library
(e.g. with GPU specific library) cannot be unregistered by the gpudev library.
+CPU mapping
+~~~~~~~~~~~~~~~~~~~
+
+gpudev can map into the CPU address space a GPU memory address allocated with
gpudev.
+gpudev returns a pointer the CPU can use to access (ready or write) GPU memory.
+Later, it's also possible to unmap that memory with gpudev.
+GPU memory CPU mapped outside of the gpudev library (e.g. with GPU specific
library)
+cannot be unmapped by the gpudev library.
+
Memory Barrier
~~~~~~~~~~~~~~
diff --git a/drivers/gpu/cuda/cuda.c b/drivers/gpu/cuda/cuda.c
index 0ece1bb612..408b659fce 100644
--- a/drivers/gpu/cuda/cuda.c
+++ b/drivers/gpu/cuda/cuda.c
@@ -1177,6 +1177,8 @@ cuda_gpu_probe(__rte_unused struct rte_pci_driver
*pci_drv, struct rte_pci_devic
dev->ops.mem_free = cuda_mem_free;
dev->ops.mem_register = cuda_mem_register;
dev->ops.mem_unregister = cuda_mem_unregister;
+ dev->ops.mem_cpu_map = NULL;
+ dev->ops.mem_cpu_unmap = NULL;
dev->ops.wmb = cuda_wmb;
rte_gpu_complete_new(dev);
diff --git a/lib/gpudev/gpudev.c b/lib/gpudev/gpudev.c
index 59e2169292..ce92d63257 100644
--- a/lib/gpudev/gpudev.c
+++ b/lib/gpudev/gpudev.c
@@ -640,6 +640,67 @@ rte_gpu_mem_unregister(int16_t dev_id, void *ptr)
return GPU_DRV_RET(dev->ops.mem_unregister(dev, ptr));
}
+void *
+rte_gpu_mem_cpu_map(int16_t dev_id, size_t size, void *ptr)
+{
+ struct rte_gpu *dev;
+ void *ptr_out;
+ int ret;
+
+ dev = gpu_get_by_id(dev_id);
+ if (dev == NULL) {
+ GPU_LOG(ERR, "mem CPU map for invalid device ID %d", dev_id);
+ rte_errno = ENODEV;
+ return NULL;
+ }
+
+ if (dev->ops.mem_cpu_map == NULL) {
+ GPU_LOG(ERR, "mem CPU map not supported");
+ rte_errno = ENOTSUP;
+ return NULL;
+ }
+
+ if (ptr == NULL || size == 0) /* dry-run */
+ return NULL;
+
+ ret = GPU_DRV_RET(dev->ops.mem_cpu_map(dev, size, ptr, &ptr_out));
+
+ switch (ret) {
+ case 0:
+ return ptr_out;
+ case -ENOMEM:
+ case -E2BIG:
+ rte_errno = -ret;
+ return NULL;
+ default:
+ rte_errno = -EPERM;
+ return NULL;
+ }
+}
+
+int
+rte_gpu_mem_cpu_unmap(int16_t dev_id, void *ptr)
+{
+ struct rte_gpu *dev;
+
+ dev = gpu_get_by_id(dev_id);
+ if (dev == NULL) {
+ GPU_LOG(ERR, "cpu_unmap mem for invalid device ID %d", dev_id);
+ rte_errno = ENODEV;
+ return -rte_errno;
+ }
+
+ if (dev->ops.mem_cpu_unmap == NULL) {
+ rte_errno = ENOTSUP;
+ return -rte_errno;
+ }
+
+ if (ptr == NULL) /* dry-run */
+ return 0;
+
+ return GPU_DRV_RET(dev->ops.mem_cpu_unmap(dev, ptr));
+}
+
int
rte_gpu_wmb(int16_t dev_id)
{
diff --git a/lib/gpudev/gpudev_driver.h b/lib/gpudev/gpudev_driver.h
index 0ed7478e9b..0e55b00bfe 100644
--- a/lib/gpudev/gpudev_driver.h
+++ b/lib/gpudev/gpudev_driver.h
@@ -31,6 +31,8 @@ typedef int (rte_gpu_mem_alloc_t)(struct rte_gpu *dev, size_t
size, unsigned int
typedef int (rte_gpu_mem_free_t)(struct rte_gpu *dev, void *ptr);
typedef int (rte_gpu_mem_register_t)(struct rte_gpu *dev, size_t size, void
*ptr);
typedef int (rte_gpu_mem_unregister_t)(struct rte_gpu *dev, void *ptr);
+typedef int (rte_gpu_mem_cpu_map_t)(struct rte_gpu *dev, size_t size, void
*ptr_in, void **ptr_out);
+typedef int (rte_gpu_mem_cpu_unmap_t)(struct rte_gpu *dev, void *ptr);
typedef int (rte_gpu_wmb_t)(struct rte_gpu *dev);
struct rte_gpu_ops {
@@ -46,6 +48,10 @@ struct rte_gpu_ops {
rte_gpu_mem_register_t *mem_register;
/* Unregister CPU memory from device. */
rte_gpu_mem_unregister_t *mem_unregister;
+ /* Map GPU memory for CPU visibility. */
+ rte_gpu_mem_cpu_map_t *mem_cpu_map;
+ /* Unmap GPU memory for CPU visibility. */
+ rte_gpu_mem_cpu_unmap_t *mem_cpu_unmap;
/* Enforce GPU write memory barrier. */
rte_gpu_wmb_t *wmb;
};
diff --git a/lib/gpudev/rte_gpudev.h b/lib/gpudev/rte_gpudev.h
index ff3ca78c89..5cc4eb5828 100644
--- a/lib/gpudev/rte_gpudev.h
+++ b/lib/gpudev/rte_gpudev.h
@@ -452,6 +452,55 @@ int rte_gpu_mem_register(int16_t dev_id, size_t size, void
*ptr);
__rte_experimental
int rte_gpu_mem_unregister(int16_t dev_id, void *ptr);
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Map a chunk of GPU memory to make it accessible from the CPU
+ * using the memory pointer returned by the function.
+ * GPU memory has to be allocated via rte_gpu_mem_alloc().
+ *
+ * @param dev_id
+ * Device ID requiring mapped memory.
+ * @param size
+ * Number of bytes to map.
+ * Requesting 0 will do nothing.
+ * @param ptr
+ * Pointer to the GPU memory area to be mapped.
+ * NULL is a no-op accepted value.
+
+ * @return
+ * A pointer to the mapped GPU memory usable by the CPU, otherwise NULL and
rte_errno is set:
+ * - ENODEV if invalid dev_id
+ * - ENOTSUP if operation not supported by the driver
+ * - E2BIG if size is higher than limit
+ * - ENOMEM if out of space
+ * - EPERM if driver error
+ */
+__rte_experimental
+void *rte_gpu_mem_cpu_map(int16_t dev_id, size_t size, void *ptr);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Unmap a chunk of GPU memory previously mapped with rte_gpu_mem_cpu_map()
+ *
+ * @param dev_id
+ * Reference device ID.
+ * @param ptr
+ * Pointer to the memory area to be unmapped.
+ * NULL is a no-op accepted value.
+ *
+ * @return
+ * 0 on success, -rte_errno otherwise:
+ * - ENODEV if invalid dev_id
+ * - ENOTSUP if operation not supported by the driver
+ * - EPERM if driver error
+ */
+__rte_experimental
+int rte_gpu_mem_cpu_unmap(int16_t dev_id, void *ptr);
+
/**
* @warning
* @b EXPERIMENTAL: this API may change without prior notice.
diff --git a/lib/gpudev/version.map b/lib/gpudev/version.map
index 2e414c65cc..5bc5d154cd 100644
--- a/lib/gpudev/version.map
+++ b/lib/gpudev/version.map
@@ -20,8 +20,10 @@ EXPERIMENTAL {
rte_gpu_init;
rte_gpu_is_valid;
rte_gpu_mem_alloc;
+ rte_gpu_mem_cpu_map;
rte_gpu_mem_free;
rte_gpu_mem_register;
+ rte_gpu_mem_cpu_unmap;
rte_gpu_mem_unregister;
rte_gpu_wmb;
};
--
2.17.1
