Set GIC version for qemu in docs.

Change-Id: Ic631cb7615b5e5163d75bae77149d4d5b1435d11
diff --git a/docs/GettingStarted.md b/docs/GettingStarted.md
index 3d58d26..ff9023e 100644
--- a/docs/GettingStarted.md
+++ b/docs/GettingStarted.md
@@ -44,7 +44,7 @@
 used to run Hafnium on it:
 
 ``` shell
-qemu-system-aarch64 -M virt -cpu cortex-a57 -nographic -machine virtualization=true -kernel out/reference/qemu_aarch64_clang/hafnium.bin
+qemu-system-aarch64 -M virt,gic_version=3 -cpu cortex-a57 -nographic -machine virtualization=true -kernel out/reference/qemu_aarch64_clang/hafnium.bin
 ```
 
 Though it is admittedly not very useful because it doesn't have any virtual
@@ -55,7 +55,7 @@
 which will then boot into the primary Linux VM:
 
 ``` shell
-qemu-system-aarch64 -M virt -cpu cortex-a57 -nographic -machine virtualization=true -kernel out/reference/qemu_aarch64_clang/hafnium.bin -initrd initrd.img -append "rdinit=/sbin/init"
+qemu-system-aarch64 -M virt,gic_version=3 -cpu cortex-a57 -nographic -machine virtualization=true -kernel out/reference/qemu_aarch64_clang/hafnium.bin -initrd initrd.img -append "rdinit=/sbin/init"
 ```
 
 ## Running tests