vmxnet3: introduce command to register memory region

In vmxnet3 version 3, the emulation added support for the vmxnet3 driver
to communicate information about the memory regions the driver will use
for rx/tx buffers. The driver can also indicate which rx/tx queue the
memory region is applicable for. If this information is communicated
to the emulation, the emulation will always keep these memory regions
mapped, thereby avoiding the mapping/unmapping overhead for every packet.

Currently, Linux vmxnet3 driver does not leverage this capability. The
feasibility of using this approach for the Linux vmxnet3 driver will be
investigated independently and if possible, will be part of a different
patch. This patch only exposes the emulation capability to the driver
(vmxnet3_defs.h is identical between the driver and the emulation).

Signed-off-by: Guolin Yang <[e-mail]>
Signed-off-by: Shrikrishna Khare <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/vmxnet3/vmxnet3_defs.h

···
 	VMXNET3_CMD_RESERVED2,
 	VMXNET3_CMD_RESERVED3,
 	VMXNET3_CMD_SET_COALESCE,
+	VMXNET3_CMD_REGISTER_MEMREGS,
 
 	VMXNET3_CMD_FIRST_GET = 0xF00D0000,
 	VMXNET3_CMD_GET_QUEUE_STATUS = VMXNET3_CMD_FIRST_GET,
···
 		struct Vmxnet3_CoalesceRbc	coalRbc;
 		struct Vmxnet3_CoalesceStatic	coalStatic;
 	} coalPara;
+};
+
+struct Vmxnet3_MemoryRegion {
+	__le64					startPA;
+	__le32					length;
+	__le16					txQueueBits;
+	__le16					rxQueueBits;
+};
+
+#define MAX_MEMORY_REGION_PER_QUEUE 16
+#define MAX_MEMORY_REGION_PER_DEVICE 256
+
+struct Vmxnet3_MemRegs {
+	__le16					numRegs;
+	__le16					pad[3];
+	struct Vmxnet3_MemoryRegion		memRegs[1];
 };
 
 /* If the command data <= 16 bytes, use the shared memory directly.