qemu, qemuv8: update help text and enable GDB for qemu_v8

- tee-supplicant is started automatically since commit 1333db4d
("rootfs: start tee-supplicant on boot")
- Update qemu_v8 arguments so that GDB can be used like for qemu

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>

qemu.mk

@@ -141,18 +141,14 @@ update_rootfs: update_rootfs-common
 # Run targets
 ################################################################################
 define run-help
-	@echo "Run QEMU"
-	@echo QEMU is now waiting to start the execution
-	@echo Start execution with either a \'c\' followed by \<enter\> in the QEMU console or
-	@echo attach a debugger and continue from there.
 	@echo
-	@echo To run xtest paste the following on the serial 0 prompt
-	@echo tee-supplicant\&
-	@echo sleep 0.1
-	@echo xtest
+	@echo \* QEMU is now waiting to start the execution
+	@echo \* Start execution with either a \'c\' followed by \<enter\> in the QEMU console or
+	@echo \* attach a debugger and continue from there.
+	@echo \*
+	@echo \* To run OP-TEE tests, use the xtest command in the \'Normal World\' terminal
+	@echo \* Enter \'xtest -h\' for help.
 	@echo
-	@echo To run a single test case replace the xtest command with for instance
-	@echo xtest 1004
 endef
 
 define launch-terminal

qemu_v8.mk

@@ -190,18 +190,14 @@ update_rootfs: update_rootfs-common
 # Run targets
 ################################################################################
 define run-help
-	@echo "Run QEMU"
-	@echo QEMU is now waiting to start the execution
-	@echo Start execution with either a \'c\' followed by \<enter\> in the QEMU console or
-	@echo attach a debugger and continue from there.
 	@echo
-	@echo To run xtest paste the following on the serial 0 prompt
-	@echo tee-supplicant\&
-	@echo sleep 0.1
-	@echo xtest
+	@echo \* QEMU is now waiting to start the execution
+	@echo \* Start execution with either a \'c\' followed by \<enter\> in the QEMU console or
+	@echo \* attach a debugger and continue from there.
+	@echo \*
+	@echo \* To run OP-TEE tests, use the xtest command in the \'Normal World\' terminal
+	@echo \* Enter \'xtest -h\' for help.
 	@echo
-	@echo To run a single test case replace the xtest command with for instance
-	@echo xtest 1004
 endef
 
 define launch-terminal
@@ -229,7 +225,7 @@ run-only:
 		-nographic \
 		-serial tcp:localhost:54320 -serial tcp:localhost:54321 \
 		-machine virt,secure=on -cpu cortex-a57 -m 1057 -bios $(ARM_TF_PATH)/build/qemu/release/bl1.bin \
-		-semihosting -d unimp \
+		-s -S -semihosting-config enable,target=native -d unimp \
 		-initrd $(GEN_ROOTFS_PATH)/filesystem.cpio.gz \
 		-kernel $(LINUX_PATH)/arch/arm64/boot/Image \
 		-append 'console=ttyAMA0,38400 keep_bootcon root=/dev/vda2' \