Implement a virtual device in qemu and the driver

Author: 54shady

debug/crypto/Makefile

@@ -0,0 +1,24 @@
+# Add your debugging flag (or not) to CFLAGS
+ifeq ($(DEBUG),y)
+DEBFLAGS = -O -g -DSCULL_DEBUG # "-O" is needed to expand inlines
+else
+DEBFLAGS = -O2
+endif
+
+obj-m := crypto-drv.o
+KERNELDIR ?= /lib/modules/$(shell uname -r)/build
+CC ?= gcc
+PWD := $(shell pwd)
+
+modules:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
+
+clean:
+	rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions modules.order Module.symvers
+
+depend .depend dep:
+	$(CC) $(CFLAGS) -M *.c > .depend
+
+ifeq (.depend,$(wildcard .depend))
+include .depend
+endif

debug/crypto/README.md

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+# qemu中虚拟设备实现
+
+参考书:How to Develop Embedded Software Using The QEMU Machine Emulator.pdf
+
+## 设备和驱动对应的代码
+
+crypto.c : virtual device in qemu
+crypto-drv.c : driver for crypto
+
+## 代码准备
+
+### 将设备添加到qemu中
+
+qemu code(将crypto.c放入hw/misc/下进行编译)
+
+	git checkout 59e1b8a22e
+
+Compile qemu and run
+
+	./configure --target-list=x86_64-softmmu \
+		--extra-ldflags="`pkg-config --libs openssl`"
+
+	qemu/build/x86_64-softmmu/qemu-system-x86_64 \
+		-drive file=/path/to/system.qcow2 \
+		-smp 2 -m 1024 -enable-kvm \
+		-device pci-crypto,aes_cbc_256="abc" \
+		-netdev tap,id=nd0,ifname=tap0,script=./nat_up.py,downscript=./nat_down.py \
+		-device e1000,netdev=nd0,mac=52:54:00:12:34:27
+
+### 直接在当前目录编译对应的设备驱动模块(crypto-drv.c, Makefile)
+
+	make
+
+## 调试
+
+### PCI寄存器的查看和修改(使用setpci)
+
+进系统后查看pci设备寄存器(通用)
+
+	setpci --dumpregs
+
+	00 W VENDOR_ID
+	02 W DEVICE_ID
+	04 W COMMAND
+	06 W STATUS
+	08 B REVISION
+	09 B CLASS_PROG
+	...
+	10 L BASE_ADDRESS_0
+
+用lspci -n 找到对应设备的BDF值(在驱动中定义了vendorId 0x2222, deviceId 0x1111)
+
+	00:03.0 00ff: 1111:2222
+
+查看设备对应寄存器的值(比如查看VENDOR_ID, 由dumpregs可知寄存器偏移量为00)
+
+	setpci -s 00:03.0 00.w
+
+再比如查看device id
+
+	setpci -s 00:03.0 02.w
+
+查看设备的bar0的地址
+
+	setpci -s 00:03.0 10.l
+
+或者使用lspci查看(下面的0xfebf1000就是bar0地址, 即mmio的地址)
+
+	lspci -vvvv -xxxx -s 00:03.0
+	Region 0: Memory at febf1000 (32-bit, non-prefetchable) [size=4K]
+
+或者通过qemu monitor查看也能查看到该地址
+
+	(qemu) info qtree
+	(qemu) info mtree
+
+### 使用[devmem](https://github.com/VCTLabs/devmem2)工具来调试
+
+编译工具
+
+	gcc devmem2.c -o devmem
+
+下面命令会调用到mmio的read函数
+
+	./devmem 0xfebf1000 b
+	./devmem 0xfebf1000 w
+	./devmem 0xfebf1000 l
+
+写mmio空间的第二个地址0xfebf1000 + 2,命令是1:对应的是reset
+
+	./devmem 0xfebf1002 b 1
+
+Encrypt:命令是2
+
+	./devmem 0xfebf1002 b 2
+
+Decrypt:命令是3
+
+	./devmem 0xfebf1002 b 3
+
+Enable interrupt
+
+	./devmem 0xfebf1003 b 2
+
+Disable interrupt
+
+	./devmem 0xfebf1003 b 0
+
+### 其它信息查看
+
+查看设备对应的io空间
+
+	grep mycrypto /proc/iomem
+		febf1000-febf1fff : mycrypto
+
+查看驱动对应的符号表
+
+	grep crypto_drv  /proc/kallsyms